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InnoDB Storage Engine: An erroneous assertion could occur, in debug builds only, when creating an index on a column containing zero-length values (that is, ''). (Bug #13654923)

InnoDB Storage Engine: A DDL operation such as ALTER TABLE ... ADD COLUMN could stall, eventually timing out with an Error 1005: Can't create table message referring to fil_rename_tablespace. (Bug #13636122, Bug #62100, Bug #63553)

InnoDB Storage Engine: A DDL operation for an InnoDB table could cause a busy MySQL server to halt with an assertion error:

InnoDB: Failing assertion: trx->error_state == DB_SUCCESS 

The error occurred if the DDL operation was run while all 1023 undo slots were in use by concurrent transactions. This error was less likely to occur in MySQL 5.5 and 5.6, because raising the number of InnoDB undo slots increased the number of simultaneous transactions (corresponding to the number of undo slots) from 1K to 128K. (Bug #12739098, Bug #62401)

InnoDB Storage Engine: Server startup could produce an error for temporary tables using the InnoDB storage engine, if the path in the $TMPDIR variable ended with a / character. The error log would look like:

120202 19:21:26  InnoDB: Operating system error number 2 in a file operation. 
InnoDB: The error means the system cannot find the path specified. 
InnoDB: If you are installing InnoDB, remember that you must create 
InnoDB: directories yourself, InnoDB does not create them. 
120202 19:21:26  InnoDB: Error: trying to open a table, but could not 
InnoDB: open the tablespace file './t/#sql7750_1_0.ibd'! 
InnoDB: Have you moved InnoDB .ibd files around without using the 
InnoDB: commands DISCARD TABLESPACE and IMPORT TABLESPACE? 
InnoDB: It is also possible that this is a temporary table #sql..., 
InnoDB: and MySQL removed the .ibd file for this. 

The workaround for the problem was to create a similar temporary table again, copy its .frm file to tmpdir under the name mentioned in the error message (for example, #sql123.frm) and restart mysqld with tmpdir set to its normal value without a trailing slash, for example /var/tmp. On startup, MySQL would see the .frm file and issue DROP TABLE for the orphaned temporary table. (Bug #11754376, Bug #45976)

Replication: Statements that wrote to tables with AUTO_INCREMENT columns based on an unordered SELECT from another table could lead to the master and the slave going out of sync, as the order in which the rows are retrieved from the table may differ between them. Such statements include any INSERT ... SELECT, REPLACE ... SELECT, or CREATE TABLE ... SELECT statement. Such statements are now marked as unsafe for statement-based replication, which causes the execution of one to throw a warning, and forces the statement to be logged using the row-based format if the logging format is MIXED. (Bug #11758263, Bug #50440)

myisam_sort_buffer_size could not be set larger than 4GB on 64-bit systems. (Bug #45702, Bug #11754145)

A new CMake option, MYSQL_PROJECT_NAME, can be set on Windows or Mac OS X to be used in the project name. (Bug #13551687)

Performance: InnoDB Storage Engine: Memory allocation for InnoDB tables was reorganized to reduce the memory overhead for large numbers of tables or partitions, avoiding situations where the “resident set size” could grow regardless of FLUSH TABLES statements. The problem was most evident for tables with large row size. Some of the memory that was formerly allocated for every open table is now allocated only when the table is modified for the first time. (Bug #11764622, Bug #57480)

Incompatible Change: An earlier change (in MySQL 5.1.62 and 5.5.21) was found to modify date-handling behavior in General Availability-status series (MySQL 5.1 and 5.5). This change has been reverted.

The change was that several functions became more strict when passed a DATE() function value as their argument, thus they rejected incomplete dates with a day part of zero. These functions were affected: CONVERT_TZ(), DATE_ADD(), DATE_SUB(), DAYOFYEAR(), LAST_DAY(), TIMESTAMPDIFF(), TO_DAYS(), TO_SECONDS(), WEEK(), WEEKDAY(), WEEKOFYEAR(), YEARWEEK(). The previous behavior has been restored. (Bug #13458237)

InnoDB Storage Engine: A Valgrind error was fixed in the function os_aio_init(). (Bug #13612811)

InnoDB Storage Engine: The server could crash when creating an InnoDB temporary table under Linux, if the $TMPDIR setting points to a tmpfs filesystem and innodb_use_native_aio is enabled, as it is by default in MySQL 5.5.4 and higher. The entry in the error log looked like:

101123  2:10:59  InnoDB: Operating system error number 22 in a file operation. 
InnoDB: Error number 22 means 'Invalid argument'.

The crash occurred because asynchronous I/O is not supported on tmpfs in some Linux kernel versions. The workaround was to turn off the innodb_use_native_aio setting or use a different temporary directory. The fix causes InnoDB to turn off the innodb_use_native_aio setting automatically if it detects that the temporary file directory does not support asynchronous I/O. (Bug #13593888, Bug #11765450, Bug #58421)

InnoDB Storage Engine: References to C preprocessor symbols and macros HAVE_purify, UNIV_INIT_MEM_TO_ZERO, and UNIV_SET_MEM_TO_ZERO were removed from the InnoDB source code. They were only used in debug builds instrumented for Valgrind. They are replaced by calls to the UNIV_MEM_INVALID() macro. (Bug #13418934)

InnoDB Storage Engine: The MySQL server could halt with an assertion error:

InnoDB: Failing assertion: page_get_n_recs(page) > 1

Subsequent restarts could fail with the same error. The error occurred during a purge operation involving the InnoDB change buffer. The workaround was to set the configuration option innodb_change_buffering=inserts. (Bug #13413535, Bug #61104)

InnoDB Storage Engine: With 1024 concurrent InnoDB transactions running concurrently and the innodb_file_per_table setting enabled, a CREATE TABLE operation for an InnoDB table could fail. The .ibd file from the failed CREATE TABLE was left behind, preventing the table from being created later, after the load had dropped.

The fix adds error handling to delete the erroneous .ibd file. This error was less likely to occur in MySQL 5.5 and 5.6, because raising the number of InnoDB undo slots increased the number of simultaneous transactions needed to trigger the bug, from 1K to 128K. (Bug #12400341)

Replication: Executing mysqlbinlog with the --start-position=N option, where N was equal either to 0 or to a value greater than the length of the dump file, caused it to crash.

This issue was introduced in MySQL 5.5.18 by the fix for Bug #32228 and Bug #11747416. (Bug #13593869, Bug #64035)

Replication: On Windows replication slave hosts, STOP SLAVE took an excessive length of time to complete when the master was down. (Bug #11752315, Bug #43460)

A query that used an index on a CHAR column referenced in a BETWEEN clause could return invalid results. (Bug #13463488, Bug #63437)

Expressions that compared a BIGINT column with any non-integer constant were performed using integers rather than decimal or float values, with the result that the constant could be truncated. This could lead to any such comparison that used <, >, <=, >=, =, !=/<>, IN, or BETWEEN yielding false positive or negative results. (Bug #13463415, Bug #11758543, Bug #63502, Bug #50756)

When the optimizer performed conversion of DECIMAL values while evaluating range conditions, it could produce incorrect results. (Bug #13453382)

When running mysqldump with both the --single-transaction and --flush-logs options, the flushing of the log performed an implicit COMMIT (see Section 12.3.3, “Statements That Cause an Implicit Commit”), causing more than one transaction to be used and thus breaking consistency. (Bug #12809202, Bug #61854)

It was possible in the event of successive failures for mysqld_safe to restart quickly enough to consume excessive amounts of CPU. Now, on systems that support the sleep and date system utilities, mysqld_safe checks to see whether it has restarted more than 5 times in the current second, and if so, waits 1 second before attempting another restart. (Bug #11761530, Bug #54035)

When used with the --xml option, mysqldump --routines failed to dump any stored routines, triggers, or events. (Bug #11760384, Bug #52792)

It was possible on replication slaves where FEDERATED tables were in use to get timeouts on long-running operations, such as Error 1160 Got an error writing communication packets. The FEDERATED tables did not need to be replicated for the issue to occur. (Bug #11758931, Bug #51196)

References: See also Bug #12896628, Bug #61790.

If an attempt to initiate a statement failed, the issue could not be reported to the client because it was not prepared to receive any error messages prior to the execution of any statement. Since the user could not execute any queries, they were simply disconnected without providing a clear error.

After the fix for this issue, the client is prepared for an error as soon as it attempts to initiate a statement, so that the error can be reported prior to disconnecting the user. (Bug #11755281, Bug #47032)

Using myisamchk with the sort recover method to repair a table having fixed-width row format could cause the row pointer size to be reduced, effectively resulting in a smaller maximum data file size. (Bug #48848, Bug #11756869)

On Windows, the server incorrectly constructed the full path name of the plugin binary for INSTALL PLUGIN and CREATE FUNCTION ... SONAME. (Bug #45549, Bug #11754014)

The stored routine cache was subject to a small memory leak that over time or with many routines being used could result in out-of-memory errors. (Bug #44585, Bug #11753187)

A new server option, --slow-start-timeout, controls the Windows service control manager's service start timeout. The value is the maximum number of milliseconds that the service control manager waits before trying to kill the MySQL service during startup. The default value is 15000 (15 seconds). If the MySQL service takes too long to start, you may need to increase this value. A value of 0 means there is no timeout. (Bug #45546, Bug #11754011)

Performance: InnoDB Storage Engine: This fix improved the efficiency and concurrency of freeing pages in the InnoDB buffer pool when performing a DROP TABLE for an InnoDB table when the innodb_file_per_table option is enabled.

This change is most noticeable for systems with large buffer pools. During the drop operation, one traversal of the buffer pool memory structure is changed from the LRU list (the entire buffer pool) to the flush list (a much smaller structure). The LRU scanning is reduced, but not entirely eliminated. The buffer pool mutex is also released periodically, so that if the drop operation takes significant time, other threads can proceed concurrently. (Bug #11759044, Bug #51325)

Important Change: Replication: Setting an empty user in a CHANGE MASTER TO statement caused an invalid internal result and is no longer permitted. Trying to use MASTER_USER='' or setting MASTER_PASSWORD while leaving MASTER_USER unset causes the statement to fail with an error. (Bug #13427949)

Important Change: Replication: Moving the binary log file, relay log file, or both files to a new location, then restarting the server with a new value for --log-bin, --relay-log, or both, caused the server to abort on start. This was because the entries in the index file overrode the new location. In addition, paths were calculated relative to datadir (rather than to the --log-bin or --relay-log values).

The fix for this problem means that, when the server reads an entry from the index file, it now checks whether the entry contains a relative path. If it does, the relative part of the path is replaced with the absolute path set using the --log-bin or --relay-log option. An absolute path remains unchanged; in such a case, the index must be edited manually to enable the new path or paths to be used. (Bug #11745230, Bug #12133)

InnoDB Storage Engine: When doing a live downgrade from MySQL 5.6.4 or later, with innodb_page_size set to a value other than 16384, now the earlier MySQL version reports that the page size is incompatible with the older version, rather than crashing or displaying a “corruption” error. (Bug #13116225)

InnoDB Storage Engine: Certain CREATE TABLE statements could fail for InnoDB child tables containing foreign key definitions. This problem affected Windows systems only, with the setting lower_case_table_names=0. It was a regression from MySQL bug #55222. (Bug #13083023, Bug #60229)

InnoDB Storage Engine: Issuing INSERT...ON DUPLICATE KEY statements for InnoDB tables from concurrent threads could cause a deadlock, particularly with the INSERT...ON DUPLICATE KEY UPDATE form. The problem could also be triggered by issuing multiple INSERT IGNORE statements. The fix avoids deadlocks caused by the same row being accessed by more than one transaction. Deadlocks could still occur when multiple rows are inserted and updated simultaneously by different transactions in inconsistent order; those types of deadlocks require the standard error handling on the application side, of re-trying the transaction. (Bug #11759688, Bug #52020, Bug #12842206)

An incorrect InnoDB assertion could cause the server to halt. This issue only affected debug builds. The assertion referenced the source file btr0pcur.ic and the variable cursor->pos_state. (Bug #13358468)

Locale information for FORMAT() function instances was lost in view definitions. (Bug #63020, Bug #13344643)

The handle_segfault() signal-handler code in mysqld could itself crash due to calling unsafe functions. (Bug #54082, Bug #11761576)

Enabling myisam_use_mmap could cause the server to crash. (Bug #48726, Bug #11756764)

Concurrent access to ARCHIVE tables could cause corruption. (Bug #42784, Bug #11751793)

Replication: Previously, replication slaves could connect to the master server through master accounts that use nonnative authentication, except Windows native authentication. This is now also true for Windows native authentication.

Performance of metadata locking operations on Windows XP systems was improved by instituting a cache for metadata lock objects. This permits the server to avoid expensive operations for creation and destruction of synchronization objects on XP. A new system variable, metadata_locks_cache_size, permits control over the size of the cache. The default size is 1024. (Bug #12695572)

InnoDB Storage Engine: An internal deadlock could occur within InnoDB, on a server doing a substantial amount of change buffering for DML operations, particularly DELETE statements. (Bug #13340047)

Replication: When a statement containing a large number of rows to be applied on a slave table that does not contain a primary key, a considerable amount of time can be needed to find and change all the rows that are to be changed. The current fix helps diagnose this issue by printing a message to the error log if the execution time for a given statement replicated using row-based replication takes more than 60 seconds. log_warnings must be greater than 1 for this message to be printed to the error log. (Bug #11760927, Bug #53375)

Rounding DBL_MAX returned DBL_MAX, not 'inf'. (Bug #13261955)

mysql_upgrade did not upgrade the system tables or create the mysql_upgrade_info file when run with the --write-binlog or --skip-write-binlog option. (Bug #60223, Bug #11827359)

If a plugin was uninstalled, thread local variables for plugin variables of string type with wth PLUGIN_VAR_MEMALLOC flag were not freed. (Bug #56652, Bug #11763882)

Deadlock could occur when these four things happened at the same time: 1) An old dump thread was waiting for the binary log to grow. 2) The slave server that replicates from the old dump thread tried to reconnect. During reconnection, the new dump thread tried to kill the old dump thread. 3) A KILL statement tried to kill the old dump thread. 4) An INSERT statement caused a binary log rotation. (Bug #56299, Bug #11763573)

Upgrading from an Advanced GPL RPM package to an Advanced RPM package did not work. Now on Linux it is possible to use rpm -U to replace any installed MySQL product by any other of the same release family. It is not necessary to remove the old produce with rpm -e first. (Bug #11886309)

Performance: InnoDB Storage Engine: The process of deallocating the InnoDB Adaptive Hash Index was made faster, during shutdown or when turning off the AHI with the statement:

SET GLOBAL innodb_adaptive_hash_index=OFF;

(Bug #13006367, Bug #62487)

Incompatible Change: Replication: The statements in the following list are now marked as unsafe for statement-based replication. This is due to the fact that each of these statements depends on the results of a SELECT statement whose order cannot always be determined. When using STATEMENT logging mode, a warning is issued in the binary log for any of these statements; when using MIXED logging mode, the statement is logged using the row-based format.

When upgrading, you should note the use of these statements in your applications, keeping in mind that a statement that inserts or replaces rows obtained from a SELECT can take up many times as much space in the binary log when logged using row-based format than when only the statement itself is logged. Depending on the number and size of the rows selected and inserted (or replaced) by any such statements, the difference in size of the binary log after the logging of these statements is switched from statement-based to row-based can potentially be several orders of magnitude. See Section 15.1.2.1, “Advantages and Disadvantages of Statement-Based and Row-Based Replication”. (Bug #11758262, Bug #50439)

InnoDB Storage Engine: Fixed a compilation problem that affected the InnoDB source code with gcc 4.6.1. The affected InnoDB source file was btr/btr0cur.c. (Bug #13116045)

InnoDB Storage Engine: An UPDATE statement for an InnoDB table could hang. The issue affects tables using the Barracuda file format and having multiple indexes on column prefixes. The size of an undo log record could exceed the page size, even though the total size of the column prefixes was less than the page size (usually 16KB). In MySQL 5.5 and higher, this error is now reported using the new code ER_UNDO_RECORD_TOO_BIG. In MySQL 5.1 with the InnoDB Plugin, this error is reported using the existing code ER_TOO_BIG_ROWSIZE. (Bug #12547647)

Replication: A replication master could send damaged events to slaves after the binary log disk on the master became full. To correct this issue, only complete events are now pushed by the master dump thread to the slave I/O thread. In addition, the error text that the master sends to the slave when an incomplete event is found now states that the incomplete event may have been caused by running out of disk space on the master, and provides coordinates of the first and the last event bytes read. (Bug #11747416, Bug #32228)

References: See also Bug #64035, Bug #13593869.

During the table-opening process, memory was allocated and later freed that was needed view loading, even for statements that did not use views. These unnecessary allocation and free operations are no longer done. (Bug #13116518)

mysql_plugin mishandled the --plugin-ini, --mysqld, and --my-print-defaults options under some circumstances. (Bug #12968815)

mysql_plugin returned the wrong error code from failed server bootstrap execution. (Bug #12968567)

Several improvements were made to the libedit library bundled with MySQL distributions, and that is available for all platforms that MySQL supports except Windows.

(Bug #12605400, Bug #12613725, Bug #12618092, Bug #12624155, Bug #12617651, Bug #12605388)

ARCHIVE tables with NULL columns could cause server crashes or become corrupt under concurrent load. (Bug #51252, Bug #11758979)

OPTIMIZE TABLE could corrupt MyISAM tables if myisam_use_mmap was enabled. (Bug #49030, Bug #11757032)

A query that selected a GROUP_CONCAT() function result could return different values depending on whether an ORDER BY of the function result was present. (Bug #41090, Bug #11750518)

For FEDERATED tables, loss of connection to the remote table during some insert operations could cause a server crash. (Bug #34660, Bug #11747970)

Replication: Previously, replication slaves could connect to the master server only through master accounts that use native authentication. Now replication slaves can also connect through master accounts that use nonnative authentication (except Windows native authentication) if the required client-side plugin is installed on the slave side in the directory named by the slave plugin_dir system variable. The exception for Windows is lifted in MySQL 5.5.19. (Bug #12897501)

The make_win_bin_dist script is no longer used and has been removed from MySQL distributions and the manual. (Bug #58241)

MEMORY table creation time is now available in the CREATE_TIME column of the INFORMATION_SCHEMA.TABLES table and the Create_time column of SHOW TABLE STATUS output. (Bug #51655, Bug #11759349)

Performance: InnoDB Storage Engine: This fix improves the performance of instrumentation code for InnoDB buffer pool operations. (Bug #12950803, Bug #62294)

InnoDB Storage Engine: Lookups using secondary indexes could give incorrect matches under a specific set of conditions. The conditions involve an index defined on a column prefix, for a BLOB or other long column stored outside the index page, with a table using the Barracuda file format. (Bug #12601439, Bug #12543666)

InnoDB Storage Engine: This fix corrects cases where the MySQL server could hang or abort with a long semaphore wait message. (This is a different issue than when these symptoms occurred during a CHECK TABLE statement.) (Bug #11766591, Bug #59733)

Internal conversion of zero to binary and back could yield a result with incorrect precision. (Bug #12911710)

Valgrind warnings generated by filesort operations were fixed. (Bug #12856915)

mysqld_safe did not properly check for an already running instance of mysqld. (Bug #11878394)

With Valgrind enabled, InnoDB semaphore wait timeouts were too low and could expire. (Bug #11765460)

The help message for mysql_install_db did not indicate that it supports the --defaults-file, --defaults-extra-file and --no-defaults options. (Bug #58898, Bug #11765888)

An assertion designed to detect zero-length sort keys also was raised when the entire key set fit in memory. (Bug #58200, Bug #11765254)

myisampack could create corrupt FULLTEXT indexes when compressing tables. (Bug #53646, Bug #11761180)

A linking problem prevented the FEDERATED storage engine plugin from loading. (Bug #40942, Bug #11750417)

The default thread-handling model in MySQL Server executes statements using one thread per client connection. As more clients connect to the server and execute statements, overall performance degrades. Commercial distributions of MySQL now include a thread pool plugin that provides an alternative thread-handling model designed to reduce overhead and improve performance. The plugin implements a thread pool that increases server performance by efficiently managing statement execution threads for large numbers of client connections.

The thread pool addresses several problems of the one thread per connection model:

On Windows, the thread pool plugin requires Windows Vista or newer. On Linux, the plugin requires kernel 2.6.9 or newer.

For more information, see Section 7.11.6, “The Thread Pool Plugin”.

Commercial distributions of MySQL now include two plugins that enable MySQL Server to use external authentication methods to authenticate MySQL users:

These authentication plugins enable MySQL Server to accept connections from users defined outside the MySQL grant tables. They also support the MySQL proxy-user capability. Each plugin can return to MySQL a user name different from the login user, which means that the plugin can return the MySQL user that defines the privileges the externally authenticated user should have. For example, an external user named joe can connect and have the privileges of the MySQL user named developer.

The server-side PAM and Windows authentication plugins are included only in commercial distributions. They are not included in MySQL community distributions. The client-side plugins with which they communicate are included in all distributions, including community distributions. This permits clients from any release to connect to a server that has the server-side plugin loaded.

For more information about these plugins, see Section 5.5.6.2, “The PAM Authentication Plugin”, and Section 5.5.6.3, “The Windows Native Authentication Plugin”. For general information about pluggable authentication in MySQL, see Section 5.5.6, “Pluggable Authentication”. For proxy user information, see Section 5.5.7, “Proxy Users”.

Important Change: Replication: The RESET SLAVE statement has been extended with an ALL keyword. In addition to deleting the master.info, relay-log.info, and all relay log files, RESET SLAVE ALL also clears all connection information otherwise held in memory following execution of RESET SLAVE. (Bug #11809016)

The thread pool plugin should be loaded at server startup, and not loaded or unloaded at runtime. An error now occurs for attempts to load or unload it with the INSTALL PLUGIN or UNINSTALL PLUGIN statement.

Some plugins operate in such a matter that they should be loaded at server startup, and not loaded or unloaded at runtime. The plugin API now supports marking plugins this way. The st_mysql_plugin structure now has a flags member, which can be set to the OR of the applicable flags. The PLUGIN_OPT_NO_INSTALL flag indicates that the plugin cannot be loaded at runtime with the INSTALL PLUGIN statement. This is appropriate for plugins that must be loaded at server startup with the --plugin-load option. The PLUGIN_OPT_NO_UNINSTALL flag indicates that the plugin cannot be unloaded at runtime with the UNINSTALL PLUGIN statement.

The new member changes the interface, so the plugin interface version, MYSQL_PLUGIN_INTERFACE_VERSION, has been incremented from 0x0102 to 0x0103. Plugins that require access to the new member must be recompiled to use version 0x0103 or higher.

A new utility, mysql_plugin, enables MySQL administrators to manage which plugins a MySQL server loads. It provides an alternative to manually specifying the --plugin-load option at server startup or using the INSTALL PLUGIN and UNINSTALL PLUGIN statements at runtime. See Section 4.4.4, “mysql_plugin — Configure MySQL Server Plugins”.

Performance: InnoDB Storage Engine: This fix improves the performance of operations on VARCHAR(N) columns in InnoDB tables, where N is declared as a large value but the actual string values in the table are short. (Bug #12835650)

Performance: InnoDB Storage Engine: The “random read-ahead” feature that was removed from the InnoDB Plugin is now available again. Because it is only helpful for certain workloads, it is turned off by default. To turn it on, enable the innodb_random_read_ahead configuration option. Because this feature can improve performance in some cases and reduce performance in others, before relying on this setting, benchmark both with and without the setting enabled. (Bug #12356373)

Incompatible Change: Handling of a date-related assertion was modified.

However, a consequence of this change is that several functions become more strict when passed a DATE() function value as their argument and reject incomplete dates with a day part of zero. These functions are affected: CONVERT_TZ(), DATE_ADD(), DATE_SUB(), DAYOFYEAR(), LAST_DAY(), TIMESTAMPDIFF(), TO_DAYS(), TO_SECONDS(), WEEK(), WEEKDAY(), WEEKOFYEAR(), YEARWEEK(). Because this changes date-handling behavior in General Availability-status series (MySQL 5.1 and 5.5), it was reverted in 5.1.62 and 5.5.21. The change is retained in MySQL 5.6.

References: See also Bug #13458237.

InnoDB Storage Engine: The DATA_LENGTH column in the INFORMATION_SCHEMA.TABLES table now correctly reports the on-disk sizes of tablespaces for InnoDB compressed tables. (Bug #12770537)

InnoDB Storage Engine: With the configuration settings innodb_file_per_table=1 and innodb_file_format=Barracuda, inserting a column value greater than half the page size, and including that column in a secondard index, could cause a crash when that column value was updated. (Bug #12637786)

InnoDB Storage Engine: Unused functions were removed from the internal InnoDB code related to mini-transactions, to clarify the logic. (Bug #12626794, Bug #61240)

Replication: Processing of corrupted table map events could cause the server to crash. This was especially likely if the events mapped different tables to the same identifier, such as could happen due to Bug #56226.

Now, before applying a table map event, the server checks whether the table has already been mapped with different settings, and if so, an error is raised and the slave SQL thread stops. If it has been mapped with the same settings, or if the table is set to be ignored by filtering rules, there is no change in behavior: the event is skipped and IDs are not checked. (Bug #44360, Bug #11753004)

References: See also Bug #11763509.

The metadata locking subsystem added too much overhead for INFORMATION_SCHEMA queries that were processed by opening only .frm or .TRG files and had to scan many tables. For example, SELECT COUNT(*) FROM INFORMATION_SCHEMA.TRIGGERS was affected. (Bug #12828477)

Compilation failed on Mac OS X 10.7 (Lion) with a warning: Implicit declaration of function 'pthread_init' (Bug #12779790)

With profiling disabled or not compiled in, set_thd_proc_info() unnecessarily checked file name lengths. (Bug #12756017)

References: This bug is a regression of Bug #59273.

A DBUG_ASSERT added by Bug #11792200 was overly aggressive in raising assertions. (Bug #12537160)

CHECK TABLE and REPAIR TABLE failed to find problems with MERGE tables that had underlying tables missing or with the wrong storage engine. Issues were reported only for the first underlying table. (Bug #11754210)

(5 DIV 2) and (5.0 DIV 2) produced different results (2 versus 3) because the result of the latter expression was not truncated before conversion to integer. This differed from the behavior in MySQL 5.0 and 5.1. Now both expressions produce 2. (Bug #61676, Bug #12711164)

For a lower_case_table_names value of 1 or 2 and a database having a mixed-case name, calling a stored function using a fully qualified name including the database name failed. (Bug #60347, Bug #11840395)

SELECT DISTINCT with a deterministic stored function in the WHERE clause could produce incorrect results. (Bug #59736, Bug #11766594)

The embedded server crashed when argc = 0. (Bug #57931, Bug #12561297)

CREATE TABLE without an ENGINE option determined the default engine at parse rather than execution time. This led to incorrect results if the statement was executed within a stored program and the default engine had been changed in the meantime. (Bug #50614, Bug #11758414)

The mysql_affected_rows() C API function returned 3 (instead of 2) for INSERT ... ON DUPLICATE KEY UPDATE statements where there was a duplicated key value. (Bug #46675, Bug #11754979)

Upgrades using an RPM package recreated the test database, which is undesirable when the DBA had removed it. (Bug #45415, Bug #11753896)

The undocumented --all option for perror is deprecated and will be removed in MySQL 5.6.

Performance: InnoDB Storage Engine: The DROP TABLE command for an InnoDB table could be very slow, in a configuration with a combination of table compression, partitioning, and a large buffer pool. (Bug #12635227, Bug #61188)

InnoDB Storage Engine: A failed CREATE INDEX operation for an InnoDB table could result in some memory being allocated but not freed. This memory leak could affect tables created with the ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED setting. (Bug #12699505)

Partitioning: Auto-increment columns of partitioned tables were checked even when they were not being written to. In debug builds, this could lead to a server crash. (Bug #11765667, Bug #58655)

Partitioning: The UNIX_TIMESTAMP() function was not treated as a monotonic function for purposes of partition pruning. (Bug #11746819, Bug #28928)

Replication: If a LOAD DATA INFILE statement—replicated using statement-based replication—featured a SET clause, the name-value pairs were regenerated using a method (Item::print()) intended primarily for generating output for statements such as EXPLAIN EXTENDED, and which cannot be relied on to return valid SQL. This could in certain cases lead to a crash on the slave.

To fix this problem, the server now names each value in its original, user-supplied form, and uses that to create LOAD DATA INFILE statements for statement-based replication. (Bug #60580, Bug #11902767)

References: See also Bug #34283, Bug #11752526, Bug #43746.

Compiling the server with maintainer mode enabled failed for gcc 4.6 or higher. (Bug #12727287)

The option-parsing code for empty strings leaked memory. (Bug #12589928)

mysql_list_fields() returned incorrect character set information for character columns of views. (Bug #12337762)

Previously, an inappropriate error message was produced if a multiple-table update for an InnoDB table with a clustered primary key would update a table through multiple aliases, and perform an update that may physically move the row in at least one of these aliases. Now the error message is: Primary key/partition key update is not permitted since the table is updated both as 'tbl_name1' and 'tbl_name2' (Bug #11882110)

References: See also Bug #11764529.

ALTER TABLE {MODIFY|CHANGE} ... FIRST did nothing except rename columns if the old and new versions of the table had exactly the same structure with respect to column data types. As a result, the mapping of column name to column data was incorrect. The same thing happened for ALTER TABLE DROP COLUMN ... ADD COLUMN statements intended to produce a new version of the table with exactly the same structure as the old version. (Bug #61493, Bug #12652385)

Incorrect handling of metadata locking for FLUSH TABLES WITH READ LOCK for statements requiring prelocking caused two problems:

(Bug #61401, Bug #12641342)

The fractional part of the “Queries per second” value could be displayed incorrectly in MySQL status output (for example, in the output from mysqladmin status or the mysql STATUS command). (Bug #61205, Bug #12565712)

LOAD DATA INFILE incorrectly parsed relative data file path names that ascended more than three levels in the file system and as a consequence was unable to find the file. (Bug #60987, Bug #12403662)

For unknown users, the native password plugin reported incorrectly that no password had been specified even when it had. (Bug #59792, Bug #11766641)

For MyISAM tables, attempts to insert incorrect data into an indexed GEOMETRY column could result in table corruption. (Bug #57323, Bug #11764487)

In debug builds, Field_new_decimal::store_value() was subject to buffer overflows. (Bug #55436, Bug #11762799)

A race condition between loading a stored routine using the name qualified by the database name and dropping that database resulted in a spurious error message: The table mysql.proc is missing, corrupt, or contains bad data (Bug #47870, Bug #11756013)

Incompatible Change: In the audit plugin interface, the event_class member was removed from the mysql_event_general structure and the calling sequence for the notification function was changed. Originally, the second argument was a pointer to the event structure. The function now receives this information as two arguments: an event class number and a pointer to the event. Corresponding to these changes, MYSQL_AUDIT_INTERFACE_VERSION was increased to 0x0300.

The plugin_audit.h header file, and the NULL_AUDIT example plugin in the plugin/audit_null directory were modified per these changes. See Section 22.2.4.8, “Writing Audit Plugins”.

InnoDB Storage Engine: InnoDB now permits concurrent reads while creating a secondary index. (Bug #11853126)

References: See also Bug #11751388, Bug #11784056, Bug #11815600.

CMake configuration support on Linux now provides a boolean ENABLE_GCOV option to control whether to include support for gcov. (Bug #12549572)

Client programs now display more information for SSL errors to aid in diagnosis and debugging of connection problems. (Bug #21287, Bug #11745920)

Replication: A mistake in thread cleanup could cause a replication master to crash. (Bug #12578441)

Replication: When using row-based replication and attribute promotion or demotion (see Section 15.4.1.6.2, “Replication of Columns Having Different Data Types”), memory allocated internally for conversion of BLOB columns was not freed afterwards. (Bug #12558519)

Adding support for Windows authentication to libmysql introduced a link dependency on the system Secur32 library. The Microsoft Visual C++ link information now pulls in this library automatically. (Bug #12612143)

In some cases, memory allocated for Query_tables_list::sroutines() was not freed properly. (Bug #12429877)

After the fix for Bug #11889186, MAKEDATE() arguments with a year part greater than 9999 raised an assertion. (Bug #12403504)

An assertion could be raised due to a missing NULL value check in Item_func_round::fix_length_and_dec(). (Bug #12392636)

An assertion could be raised during two-phase commits if the binary log was used as the transaction coordinator log. (Bug #12346411)

A problem introduced in MySQL 5.5.11 caused very old (MySQL 4.0) clients to be unable to connect to the server. (Bug #61222, Bug #12563279)

Using CREATE EVENT IF NOT EXISTS for an event that already existed and was enabled caused multiple instances of the event to run. (Bug #61005, Bug #12546938)

An embedded client aborted rather than issuing an error message if it issued a TEE command (\T file_name) and the directory containing the file did not exist. This occurred because the wrong error handler was called. (Bug #57491, Bug #11764633)

ALTER EVENT could change the event status. (Bug #57156, Bug #11764334)

On some platforms, the Incorrect value: xxx for column yyy at row zzz error produced by LOAD DATA INFILE could have an incorrect value of zzz. (Bug #46895, Bug #11755168)

An attempt to install nonexistent files during installation was corrected. (Bug #43247, Bug #11752142)

On FreeBSD 64-bit builds of the embedded server, exceptions were not prevented from propagating into the embedded application. (Bug #38965, Bug #11749418)

The client-side plugin that accompanies the server-side Windows authentication plugin is now included in all MySQL distributions. This will permit clients from any release, whether commercial or community, to connect to a server that has the server-side plugin loaded. See Section 5.5.6.3, “The Windows Native Authentication Plugin” (Bug #59780, Bug #11766631)

InnoDB Storage Engine: If the server crashed while an XA transaction was prepared but not yet committed, the transaction could remain in the system after restart, and cause a subsequent shutdown to hang. (Bug #11766513, Bug #59641)

InnoDB Storage Engine: The MySQL server could hang during CREATE TABLE, OPTIMIZE TABLE, or ALTER TABLE or other DDL operation that performs a table copy for an InnoDB table, if such operations were performed by multiple sessions simultaneously. The error was reported as:

InnoDB: Error: semaphore wait has lasted > 600 seconds

(Bug #11760042, Bug #52409)

InnoDB Storage Engine: With the setting lower_case_table_names=2, inserts into InnoDB tables covered by foreign key constraints could fail after a server restart. This is a similar problem to the foreign key error in Bug #11831040 / Bug #60196 / Bug #60909, but with a different root cause and occurring on Mac OS X.

Partitioning: The internal get_partition_set() function did not take into account the possibility that a key specification could be NULL in some cases. (Bug #12380149)

Partitioning: When executing a row-ordered retrieval index merge, the partitioning handler used memory from that allocated for the table, rather than that allocated to the query, causing table object memory not to be freed until the table was closed. (Bug #11766249, Bug #59316)

Replication: When mysqlbinlog was invoked using --base64-output=decode-row and --start-position=pos, (where pos is a point in the binary log past the format description log event), a spurious error of the type shown here was generated:

malformed binlog: it does not contain any Format_description_log_event... 

However, since there is nothing unsafe about not printing the format description log event, the error has been removed for this case. (Bug #12354268)

Replication: Typographical errors appeared in the text of several replication error messages. (The word “position” was misspelled as “postion”.) (Bug #11762616, Bug #55229)

Assignments to NEW.var_name within triggers, where var_name had a BLOB or TEXT type, were not properly handled and produced incorrect results. (Bug #12362125)

XA COMMIT could fail to clean up the error state if it discovered that the current XA transaction had to be rolled back. Consequently, the next XA transaction could raise an assertion when it checked for proper cleanup of the previous transaction. (Bug #12352846)

An internal client macro reference was removed from the client_plugin.h header file. This reference made the file unusable. (Bug #60746, Bug #12325444)

For repeated invocation of some stored procedures, the server consumed memory that it did not release until the connection terminated. (Bug #60025, Bug #11848763)

The server did not check for certain invalid out of order sequences of XA statements, and these sequences raised an assertion. (Bug #59936, Bug #11766752, Bug #12348348)

With the conversion from GNU autotools to CMake for configuring MySQL, the USE_SYMDIR preprocessor symbol was omitted. This caused failure of symbolic links (described at Section 7.11.3.1, “Using Symbolic Links”). (Bug #59408, Bug #11766320)

An incorrect max_length value for YEAR values could be used in temporary result tables for UNION, leading to incorrect results. (Bug #59343, Bug #11766270)

In Item_func_in::fix_length_and_dec(), a Valgrind warning for uninitialized values was corrected. (Bug #59270, Bug #11766212)

In ROUND() calculations, a Valgrind warning for uninitialized memory was corrected. (Bug #58937, Bug #11765923)

References: This bug is a regression of Bug #33143.

Valgrind warnings caused by comparing index values to an uninitialized field were corrected. (Bug #58705, Bug #11765713)

LOAD DATA INFILE errors could leak I/O cache memory. (Bug #58072, Bug #11765141)

For LOAD DATA INFILE, multibyte character sequences could be pushed onto a stack too small to accommodate them. (Bug #58069, Bug #11765139)

Internal Performance Schema header files were unnecessarily installed publicly. (Bug #53281)

On Linux, the mysql client built using the bundled libedit did not read ~/.editrc. (Bug #49967, Bug #11757855)

The optimizer sometimes incorrectly processed HAVING clauses for queries that did not also have an ORDER BY clause. (Bug #48916, Bug #11756928)

PROCEDURE ANALYZE() could leak memory for NULL results, and could return incorrect results if used with a LIMIT clause. (Bug #48137, Bug #11756242)

With DISTINCT, CONCAT(col_name,...) returned incorrect results when the arguments to CONCAT() were columns with an integer data type declared with a display width narrower than the values in the column. (For example, if an INT(1) column contained 1111.) (Bug #4082)

When invoked with the --auto-generate-sql option, mysqlslap dropped the schema specified with the --create-schema option at the end of the test run, which may have been unexpected by the user. mysqlslap no longer drops the schema, but has a new --create-and-drop-schema option that both creates and drops a schema. (Bug #58090, Bug #11765157)

InnoDB Storage Engine: Replication: Trying to update a column, previously set to NULL, of an InnoDB table with no primary key caused replication to fail with Can't find record in 'table' on the slave. (Bug #11766865, Bug #60091)

InnoDB Storage Engine: The server could halt if InnoDB interpreted a very heavy I/O load for 15 minutes or more as an indication that the server was hung. This change fixes the logic that measures how long InnoDB threads were waiting, which formerly could produce false positives. (Bug #11877216, Bug #11755413, Bug #47183)

InnoDB Storage Engine: With the setting lower_case_table_names=2, inserts into InnoDB tables covered by foreign key constraints could fail after a server restart. (Bug #11831040, Bug #60196, Bug #60909)

Replication: Using the --server-id option with mysqlbinlog could cause format description log events to be filtered from the binary log, leaving mysqlbinlog unable to read the remainder of the log. Now such events are always read without regard to the value of this option.

As part of the the fix for this problem, mysqlbinlog now also reads rotate log events without regard to the value of --server-id. (Bug #59530, Bug #11766427)

On Windows, the server rejected client connections if no DNS server was available. (Bug #12325375)

mysql_upgrade did not properly upgrade the authentication_string column of the mysql.user table. (Bug #11936829)

InnoDB invoked some zlib functions without proper initialization. (Bug #11849231)

CREATE TABLE permitted a TABLESPACE table option but did not write the option value to the .frm file. (Bug #11769356)

Comparison of a DATETIME stored program variable and NOW() resulted in “Illegal mix of collations error” when character_set_connection was set to utf8. (Bug #60625, Bug #11926811)

Selecting from a view for which the definition included a HAVING clause failed with an error:

1356: View '...' references invalid table(s) or column(s)
or function(s) or definer/invoker of view lack rights to use them

(Bug #60295, Bug #11829681)

CREATE TABLE syntax permits specification of a STORAGE {DEFAULT|DISK|MEMORY} option. However, this value was not written to the .frm file, so that a subsequent CREATE TABLE ... LIKE for the table did not include that option.

Also, ALTER TABLE of a table that had a tablespace incorrectly destroyed the tablespace. (Bug #60111, Bug #11766883, Bug #34047, Bug #11747789)

The server permitted max_allowed_packet to be set lower than net_buffer_length, which does not make sense because max_allowed_packet is the upper limit on net_buffer_length values. Now a warning occurs and the value remains unchanged. (Bug #59959, Bug #11766769)

A missing variable initialization for Item_func_set_user_var objects could raise an assertion. (Bug #59527, Bug #11766424)

When the server was started with the --skip-innodb option, it initialized the have_innodb system variable to YES rather than DISABLED. (Bug #59393, Bug #11766306)

In Item_func_month::val_str(), a Valgrind warning for a too-late NULL value check was corrected. (Bug #59166, Bug #11766126)

In Item::get_date, a Valgrind warning for a missing NULL value check was corrected. (Bug #59164, Bug #11766124)

In extract_date_time(), a Valgrind warning for a missing end-of-string check was corrected. (Bug #59151, Bug #11766112)

In string context, the MIN() and MAX() functions did not take into account the unsignedness of a BIGINT UNSIGNED argument. (Bug #59132, Bug #11766094)

In Item_func::val_decimal, a Valgrind warning for a missing NULL value check was corrected. (Bug #59125, Bug #11766087)

In Item_func_str_to_date::val_str, a Valgrind warning for an uninitialized variable was corrected. (Bug #58154, Bug #11765216)

An assertion could be raised in Item_func_int_val::fix_num_length_and_dec() due to overflow for geometry functions. (Bug #57900, Bug #11764994)

With prepared statements, the server could attempt to send result set metadata after the table had been closed. (Bug #56115, Bug #11763413)

With lower_case_table_names=2, resolution of objects qualified by database names could fail. (Bug #50924, Bug #11758687)

SHOW EVENTS did not always show events from the correct database. (Bug #41907, Bug #11751148)

InnoDB now permits concurrent reads on a table while creating nonprimary unique indexes. (This was found to create problems and was reverted in 5.5.12.) (Bug #11784056)

Previously, Performance Schema instrumentation for both the binary log and the relay log used these instruments:

wait/io/file/sql/binlog 
wait/io/file/sql/binlog_index 
wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_index 
wait/synch/cond/sql/MYSQL_BIN_LOG::update_cond 

Now instrumentation for the relay log uses these instruments, which makes it possible to distinguish binary log and relay log events:

wait/io/file/sql/relaylog 
wait/io/file/sql/relaylog_index 
wait/synch/mutex/sql/MYSQL_RELAY_LOG::LOCK_index 
wait/synch/cond/sql/MYSQL_RELAY_LOG::update_cond 

(Bug #59658, Bug #11766528)

MySQL distributions now include an INFO_SRC file that contains information about the source distribution, such as the MySQL version from which it was created. MySQL binary distributions additionally include an INFO_BIN file that contains information about how the distribution was built, such as compiler options and feature flags. In RPM packages, these files are located in the /usr/share/doc/packages/MySQL-server directory. In tar.gz and derived packages, they are located in the Docs directory under the location where the distribution is unpacked. (Bug #42969, Bug #11751935)

Previously, for queries that were aborted due to a sort problem or terminated with KILL in the middle of a sort, the server wrote the message Sort aborted to the error log. Now the server writes more information about the cause of the error. These causes include:

(Bug #30771, Bug #11747102)

A new system variable, max_long_data_size, now controls the maximum size of parameter values that can be sent with the mysql_stmt_send_long_data() C API function. If not set at server startup, the default is the value of the max_allowed_packet system variable. This variable is deprecated. In MySQL 5.6, it is removed and the maximum parameter size is controlled by max_allowed_packet.

For the Windows installer, debug information files and the embedded MySQL server have been removed from the standard MSI distribution file to reduce the download size for the majority of users.

If these files are needed, the Zip distribution must be downloaded separately and be extracted in the installation directory, which is most probably C:\Program Files\MySQL\MySQL Server 5.5 on English systems.

Please note that upon product de-installation, these extracted files from the Zip distribution must be removed from the system manually.

The undocumented SHOW NEW MASTER statement has been removed.

Important Change: The length of the plugin column of the mysql.user system table is increased to 64 characters. This is now the same size as the name column of the mysql.plugin table. (Bug #11766610, Bug #59752)

Partitioning: A problem with a previous fix for poor performance of INSERT ON DUPLICATE KEY UPDATE statements on tables having many partitions caused the handler function for reading a row from a specific index to fail to store the ID of the partition last used. This caused some statements to fail with Can't find record errors. (Bug #59297, Bug #11766232)

References: This bug is a regression of Bug #52455.

Replication: A failed DROP DATABASE statement could break statement-based replication. (Bug #58381, Bug #11765416)

Two unused test files in storage/ndb/test/sql contained incorrect versions of the GNU Lesser General Public License. The files and the directory containing them have been removed. (Bug #11810224)

References: See also Bug #11810156.

Division of large numbers could cause stack corruption. (Bug #11792200)

The mysql_load_client_plugin() C API function did not clear the previous error. (Bug #60075, Bug #11766854)

An assertion was raised if an XA COMMIT was issued when an XA transaction had already encountered an error (such as a deadlock) that required the transaction to be rolled back. (Bug #59986, Bug #11766788)

On some systems, debug builds of comp_err could fail due to an uninitialized variable. (Bug #59906, Bug #11766729)

The server read one byte too many when trying to process an XML string lacking a closing single quote (') or double quote (") character used as an argument for UpdateXML() or ExtractValue(). (Bug #59901, Bug #11766725)

References: See also Bug #44332, Bug #11752979.

Attempting to create a spatial index on a CHAR column longer than 31 bytes led to an assertion failure if the server was compiled with safemutex support. (Bug #59888, Bug #11766714)

Aggregation followed by a subquery could produce an incorrect result. (Bug #59839, Bug #11766675)

An incorrect character set pointer passed to my_strtoll10_mb2() caused an assertion to be raised. (Bug #59648, Bug #11766519)

FIND_IN_SET() could work differently in MySQL 5.5 than in 5.1. (Bug #59405, Bug #11766317)

mysqldump did not quote database names in ALTER DATABASE statements in its output, which could cause an error at reload time for database names containing a dash. (Bug #59398, Bug #11766310)

The MYSQL_HOME environment variable was being ignored. (Bug #59280, Bug #11766219)

An invalid pathname argument for the --defaults-extra-file option of MySQL programs caused a program crash. (Bug #59234, Bug #11766184)

On Windows, the authentication_string column recently added to the mysql.user table caused the Configuration Wizard to fail. (Bug #59038, Bug #11766011)

CREATE TRIGGER and DROP TRIGGER can change the prelocking list of stored routines, but the routine cache did not detect such changes, resulting in routine execution with an inaccurate locking list. (Bug #58674, Bug #11765684)

The code for PROCEDURE ANALYSE() had a missing DBUG_RETURN statement, which could cause a server crash in debug builds. (Bug #58140, Bug #11765202)

An assertion was raised if a statement tried to upgrade a metadata lock while there was an active FLUSH TABLE tbl_list WITH READ LOCK statement. Now if a statement tries to upgrade a metadata lock in this situation, the server returns an ER_TABLE_NOT_LOCKED_FOR_WRITE error to the client. (Bug #57649, Bug #11764779)

If a multiple-table update updated a row through two aliases and the first update physically moved the row, the second update failed to locate the row. This resulted in different errors depending on the storage engine, although these errors did not accurately describe the problem:

For MyISAM, which is nontransactional, the update executed first was performed but the second was not. In addition, for two equal multiple-table update statements, one could succeed and the other fail depending on whether the record actually moved, which is inconsistent.

Now such an update returns an error if it will update a table through multiple aliases, and perform an update that may physically move the row in at least one of these aliases. (Bug #57373, Bug #11764529, Bug #55385, Bug #11762751)

SHOW WARNINGS output following EXPLAIN EXTENDED could include unprintable characters. (Bug #57341, Bug #11764503)

In some cases, SHOW WARNINGS returned an empty result when the previous statement failed. (Bug #55847, Bug #11763166)

On Windows, an object in thread local storage could be used before the object was created. (Bug #55730, Bug #11763065)

For a client connected using SSL, the Ssl_cipher_list status variable was empty and did not show the possible cipher types. (Bug #52596, Bug #11760210)

When used to upgrade tables, mysqlcheck (and mysql_upgrade, which invokes mysqlcheck) did not upgrade some tables for which table repair was found to be necessary. In particular, it failed to upgrade InnoDB tables that needed repair, leaving them in a nonupgraded state. This occurred because:

To fix the problem, the following changes were made to CHECK TABLE ... FOR UPGRADE and mysqlcheck. Because mysql_upgrade invokes mysqlcheck, these changes also fix the problem for mysql_upgrade.

(Bug #47205, Bug #11755431)

When CASE ... WHEN arguments had different character sets, 8-bit values could be referenced as utf16 or utf32 values, raising an assertion. (Bug #44793, Bug #11753363)

Bitmap functions used in one thread could change bitmaps used by other threads, raising an assertion. (Bug #43152, Bug #11752069)

Incompatible Change: The shared library version of the client library was increased to 18 to reflect ABI changes, and avoid compatibility problems with the client library in MySQL 5.1. Note that this is an incompatible change between 5.5.10 and earlier 5.5 versions, so client programs that use the 5.5 client library should be recompiled against the 5.5.10 client library. (Bug #60061, Bug #11827366)

MySQL distributions now include auth_socket, a server-side authentication plugin that authenticates clients that connect from the local host through the Unix socket file. The plugin uses the SO_PEERCRED socket option to obtain information about the user running the client program (and thus can be built only on systems that support this option). For a connection to succeed, the plugin requires a match between the login name of the connecting client user and the MySQL user name presented by the client program. For more information, see Section 5.5.6.5, “The Socket Peer-Credential Authentication Plugin”. (Bug #59017, Bug #11765993, Bug #9411, Bug #11745104)

MySQL distributions now include mysql_clear_password, a client-side authentication plugin that sends the password to the server without hashing or encryption. Although this is insecure, and thus appropriate precautions should be taken (such as using an SSL connection), the plugin is useful in conjunction with server-side plugins that must have access to the original password in clear text. For more information, see Section 5.5.6.4, “The Clear-Text Client-Side Authentication Plugin”.

The mysql_upgrade, mysqlbinlog, mysqlcheck, mysqlimport, mysqlshow, and mysqlslap clients now have --default-auth and --plugin-dir options for specifying which authentication plugin and plugin directory to use. (Bug #58139)

Boolean system variables can be enabled at run time by setting them to the value ON or OFF, but previously this did not work at server startup. Now at startup such variables can be enabled by setting them to ON or TRUE, or disabled by setting them to OFF or FALSE. Any other nonnumeric variable is invalid. (Bug #46393)

References: See also Bug #11754743, Bug #51631.

Previously, for queries that were aborted due to a sort problem, the server wrote the message Sort aborted to the error log. Now the server writes more information to provide a more specific message, such as:

Sort aborted: Out of memory (Needed 24 bytes)
Out of sort memory, consider increasing server sort buffer size
Sort aborted: Out of sort memory, consider increasing server sort
  buffer size
Sort aborted: Incorrect number of arguments for FUNCTION test.f1;
  expected 0, got 1

In addition, if the server was started with --log-warnings=2, the server writes information about the host, user, and query. (Bug #36022, Bug #11748358)

mysqldump --xml now displays comments from column definitions. (Bug #13618, Bug #11745324)

Security Fix: Bug #36544 was fixed.

InnoDB Storage Engine: Raised the number of I/O requests that each AIO helper thread could process, from 32 to 256. The new limit applies to Linux and Unix platforms; the limit on Windows remains 32. (Bug #59472)

InnoDB Storage Engine: InnoDB returned values for “rows examined” in the query plan that were higher than expected. NULL values were treated in an inconsistent way. The inaccurate statistics could trigger “false positives” in combination with the max_join_size setting, because the queries did not really examine as many rows as reported.

A new configuration option innodb_stats_method lets you specify how NULL values are treated when calculating index statistics. Allowed values are nulls_equal (the default), nulls_unequal and null_ignored. The meanings of these values are similar to those of the myisam_stats_method option. (Bug #30423)

Replication: When using the statement-based logging format, INSERT ON DUPLICATE KEY UPDATE and INSERT IGNORE statements affecting transactional tables that did not fail were not written to the binary log if they did not insert any rows. (With statement-based logging, all successful statements should be logged, whether they do or do not cause any rows to be changed.) (Bug #59338, Bug #11766266)

Replication: Formerly, STOP SLAVE stopped the slave I/O thread first and then stopped the slave SQL thread; thus, it was possible for the I/O thread to stop after replicating only part of a transaction which the SQL thread was executing, in which case—if the transaction could not be rolled back safely—the SQL thread could hang.

Now, STOP SLAVE stops the slave SQL thread first and then stops the I/O thread; this guarantees that the I/O thread can fetch any remaining events in the transaction that the SQL thread is executing, so that the SQL thread can finish the transaction if it cannot be rolled back safely. (Bug #58546, Bug #11765563)

Setting the optimizer_switch system variable to an invalid value caused a server crash. (Bug #59894, Bug #11766719)

DES_DECRYPT() could crash if the argument was not produced by DES_ENCRYPT(). (Bug #59632, Bug #11766505)

The server and client did not always properly negotiate authentication plugin names. (Bug #59453, Bug #11766356)

--autocommit=ON did not work (it set the global autocommit value to 0, not 1). (Bug #59432, Bug #11766339)

A query of the following form returned an incorrect result, where the values for col_name in the result set were entirely replaced with NULL values:

SELECT DISTINCT col_name ... ORDER BY col_name DESC;

(Bug #59308, Bug #11766241)

SHOW PRIVILEGES did not display a row for the PROXY privilege. (Bug #59275, Bug #11766216)

SHOW PROFILE could truncate source file names or fail to show function names. (Bug #59273, Bug #11766214)

DELETE or UPDATE statements could fail if they used DATE or DATETIME values with a year, month, or day part of zero. (Bug #59173)

The ESCAPE clause for the LIKE operator permits only expressions that evaluate to a constant at execution time, but aggregate functions were not being rejected. (Bug #59149, Bug #11766110)

Memory leaks detected by Valgrind, some of which could cause incorrect query results, were corrected. (Bug #59110, Bug #11766075)

There was an erroneous restriction on file attributes for LOAD DATA INFILE. (Bug #59085, Bug #11766052)

The DEFAULT_CHARSET and DEFAULT_COLLATION CMake options did not work. (Bug #58991, Bug #11765967)

An OUTER JOIN query using WHERE col_name IS NULL could return an incorrect result. (Bug #58490, Bug #11765513)

Starting the server with the --defaults-file=file_name option, where the file name had no extension, caused a server crash. (Bug #58455, Bug #11765482)

Outer joins with an empty table could produce incorrect results. (Bug #58422, Bug #11765451)

In debug builds, SUBSTRING_INDEX(FORMAT(...), FORMAT(...)) could cause a server crash. (Bug #58371, Bug #11765406)

When mysqladmin was run with the --sleep and --count options, it went into an infinite loop executing the specified command. (Bug #58221, Bug #11765270)

Some string-manipulating SQL functions use a shared string object intended to contain an immutable empty string. This object was used by the SQL function SUBSTRING_INDEX() to return an empty string when one argument was of the wrong data type. If the string object was then modified by the SQL function INSERT(), undefined behavior ensued. (Bug #58165, Bug #11765225)

Parsing nested regular expressions could lead to recursion resulting in a stack overflow crash. (Bug #58026, Bug #11765099)

The fix for Bug #25192 caused load_defaults() to add an argument separator to distinguish options loaded from option files from those provided on the command line, whether or not the application needed it. (Bug #57953, Bug #11765041)

References: See also Bug #11746296.

The mysql client went into an infinite loop if the standard input was a directory. (Bug #57450, Bug #11764598)

Outer joins on a unique key could return incorrect results. (Bug #57034, Bug #11764219)

The expression const1 BETWEEN const2 AND field was optimized incorrectly and produced incorrect results. (Bug #57030, Bug #11764215)

Some RPM installation scripts used a hardcoded value for the data directory, which could result in a failed installation for users who have a nonstandard data directory location. The same was true for other configuration values such as the PID file name. (Bug #56581, Bug #11763817)

On FreeBSD and OpenBSD, the server incorrectly checked the range of the system date, causing legal values to be rejected. (Bug #55755, Bug #11763089)

Sorting using ORDER BY AVG(DISTINCT decimal_col) caused a server crash or incorrect results. (Bug #52123, Bug #11759784)

When using ExtractValue() or UpdateXML(), if the XML to be read contained an incomplete XML comment, MySQL read beyond the end of the XML string when processing, leading to a crash of the server. (Bug #44332, Bug #11752979)

DATE_ADD() and DATE_SUB() return a string if the first argument is a string, but incorrectly returned a binary string. Now they return a character string with a collation of connection_collation. (Bug #31384, Bug #11747221)

The mysqladmin and mysqldump clients now have --default-auth and --plugin-dir options for specifying which authentication plugin and plugin directory to use. (Bug #58139, Bug #11765201)

sql_priv.h now includes an OPTION_ALLOW_BATCH flag for the transaction_allow_batching feature of MySQL Cluster. (Bug #57604)

Boolean system variables can be enabled at run time by setting them to the value ON or OFF, but previously this did not work at server startup. Now at startup such variables can be enabled by setting them to ON or TRUE. Any other nonnumeric variable is interpreted as OFF. (Bug #46393 improves on this such that ON, TRUE, OFF, and FALSE are recognized, and other values are invalid.) (Bug #51631, Bug #11759326)

References: See also Bug #11754743.

In the audit plugin interface, the MYSQL_AUDIT_CONNECTION_CLASS event class was added, and the MYSQL_AUDIT_GENERAL_STATUS subclass was added to the MYSQL_AUDIT_GENERAL_CLASS event class. The new symbol definitions can be found in the plugin_audit.h header file.

Security Fix: Bug #57952 was fixed.

Performance: InnoDB Storage Engine: InnoDB now uses the PAUSE instruction on all platforms where it is available. Previously, InnoDB used the PAUSE instruction only on Windows systems. (Bug #58666)

Performance: Queries involving InnoDB tables in the INFORMATON_SCHEMA tables TABLE_CONSTRAINTS, KEY_COLUMN_USAGE, or REFERENTIAL_CONSTRAINTS were slower than necessary because statistics were rechecked more often than required, even more so when many foreign keys were present. The improvement to this may be of particular benefit to users of MySQL Enterprise Monitor with many monitored servers or tens of thousands of tables. (Bug #43818, Bug #11752585)

Incompatible Change: When auto_increment_increment is greater than one, values generated by a bulk insert that reaches the maximum column value could wrap around rather producing an overflow error.

As a consequence of the fix, it is no longer possible for an auto-generated value to be equal to the maximum BIGINT UNSIGNED value. It is still possible to store that value manually, if the column can accept it. (Bug #39828, Bug #11749800)

Important Change: Partitioning: Date and time functions used as partitioning functions now have the types of their operands checked; use of a value of the wrong type is now disallowed in such cases. In addition, EXTRACT(WEEK FROM col_name), where col_name is a DATE or DATETIME column, is now disallowed altogether because its return value depends on the value of the default_week_format system variable. (Bug #54483, Bug #11761948)

References: See also Bug #57071, Bug #11764255.

Partitioning: InnoDB Storage Engine: The partitioning handler did not pass locking information to a table's storage engine handler. This caused high contention and thus slower performance when working with partitioned InnoDB tables. (Bug #59013)

InnoDB Storage Engine: When multiple InnoDB buffer pools were enabled, SHOW ENGINE INNODB statements displayed information about each one, but not summary information combining statistics for the entire buffer pool subsystem. Now, the aggregated information is displayed in the BUFFER POOL AND MEMORY section, and information about individual buffer pool instances is displayed in a new INDIVIDUAL BUFFER POOL INFO section. (Bug #58461)

InnoDB Storage Engine: The command to create a debug build (cmake -DWITH_DEBUG ...) now automatically sets the InnoDB debugging flag UNIV_DEBUG on all platforms. Formerly, the UNIV_DEBUG flag might not be set for Windows platforms with Visual Studio and not on OS X with Xcode. (Bug #58279)

InnoDB Storage Engine: In InnoDB status output, the value for I/O sum[] could be incorrect, displayed as a very large number. (Bug #57600)

InnoDB Storage Engine: The server could crash with an assertion error, if a stored procedure, stored function, or trigger modified one InnoDB table containing an auto-increment column, and dropped another InnoDB table containing an auto-increment column. (Bug #56228)

InnoDB Storage Engine: It was not possible to query the information_schema.INNODB_TRX table while other connections were running queries involving BLOB types. (Bug #55397, Bug #11762763)

InnoDB Storage Engine: When the lower_case_table_names variable was set to 2, InnoDB could fail to restore a mysqldump dump of a table with foreign key constraints involving case-sensitive names. (Bug #55222)

InnoDB Storage Engine: The OPTIMIZE TABLE statement reset the auto-increment counter for an InnoDB table. Now the auto-increment value is preserved across this operation. (Bug #18274)

Partitioning: Failed ALTER TABLE ... TRUNCATE PARTITION statements were written to the binary log. (Bug #58147)

Partitioning: Failed ALTER TABLE ... PARTITION statements could cause memory leaks. (Bug #56380, Bug #11763641)

References: See also Bug #46949, Bug #11755209, Bug #56996, Bug #11764187.

Replication: While an INSERT DELAYED statement with a single inserted value does not return any visible warnings, such a warning could be still written into the error log. (Bug #57666, Bug #11764793)

References: See also Bug #49567.

Replication: When closing a session that used temporary tables, binary logging could sometimes fail with a spurious Failed to write the DROP statement for temporary tables to binary log. (Bug #57288)

Replication: Due to changes made in MySQL 5.5.3, settings made in the binlog_cache_size and max_binlog_cache_size server system variables affected both the binary log statement cache (also introduced in that version) and the binary log transactional cache (formerly known simply as the binary log cache). This meant that the resources used as a result of setting either or both of these variables were double the amount expected. To rectify this problem, these variables now affect only the transactional cache. The fix for this issue also introduces two new system variables binlog_stmt_cache_size and max_binlog_stmt_cache_size, which affect only the binary log statement cache.

In addition, the Binlog_cache_use status variable was incremented whenever either cache was used, and Binlog_cache_disk_use was incremented whenever the disk space from either cache was used, which caused problems with performance tuning of the statement and transactional caches, because it was not possible to determine which of these was being exceeded when attempting to troubleshoot excessive disk seeks and related problems. This issue is solved by changing the behavior of these two status variables such that they are incremented only in response to usage of the binary log transactional cache, as well as by introducing two new status variables Binlog_stmt_cache_use and Binlog_stmt_cache_disk_use, which are incremented only by usage of the binary log statement cache.

The behavior of the max_binlog_cache_size system variable with regard to active sessions has also been changed to match that of the binlog_cache_size system variable: Previously, a change in max_binlog_cache_size took effect in existing sessions; now, as with a change in binlog_cache_size, a change in max_binlog_cache_size takes effect only in sessions begun after the value was changed.

For more information, see System variables used with the binary log, and Section 5.1.5, “Server Status Variables”. (Bug #57275, Bug #11764443)

Replication: By default, a value is generated for an AUTO_INCREMENT column by inserting either NULL or 0 into the column. Setting the NO_AUTO_VALUE_ON_ZERO server SQL mode suppresses this behavior for 0, so that it occurs only when NULL is inserted into the column.

This behavior is also followed on a replication slave (by the slave SQL thread) when applying events that have been logged on the master using the statement-based format. However, when applying events that had been logged using the row-based format, NO_AUTO_VALUE_ON_ZERO was ignored, which could lead to an assertion.

To fix this issue, the value of an AUTO_INCREMENT column is no longer generated when applying an event that was logged using the row-based row format, as this value is already contained in the changes applied on the slave. (Bug #56662)

Replication: The Binlog_cache_use and Binlog_cache_disk_use status variables were incremented twice by a change to a table using a transactional storage engine. (Bug #56343, Bug #11763611)

References: This bug is a regression of Bug #50038.

Replication: The BINLOG statement modified the values of session variables, which could lead to problems with operations such as point-in-time recovery. One such case occurred when replaying a row-based binary log which relied on setting foreign_key_checks = OFF at the session level to create and populate a set of InnoDB tables having foreign key constraints. (Bug #54903)

Replication: mysqlbinlog printed USE statements to its output only when the default database changed between events. To illustrate how this could cause problems, suppose that a user issued the following sequence of statements:

CREATE DATABASE mydb;
USE mydb;
CREATE TABLE mytable (column_definitions);
DROP DATABASE mydb;
CREATE DATABASE mydb;
USE mydb;
CREATE TABLE mytable (column_definitions);

When played back using mysqlbinlog, the second CREATE TABLE statement failed with Error: No Database Selected because the second USE statement was not played back, due to the fact that a database other than mydb was never selected.

This fix ensures that mysqlbinlog outputs a USE statement whenever it reads one from the binary log. (Bug #50914, Bug #11758677)

Replication: Previously, when a statement failed with a different error on the slave than on the master, the slave SQL thread displayed a message containing:

However, the slave has no information with which to fill in any print format specifiers for the master message, so it actually displayed the message format string. To make it clearer that the slave is not displaying the actual message as it appears on the master, the slave now indicates that the master part of the output is the message format, not the actual message. For example, previously the slave displayed information like this:

Error: "Query caused different errors on master and slave. Error
on master: 'Duplicate entry '%-.192s' for key %d' (1062), Error on
slave: 'no error' (0). Default database: 'test'. Query: 'insert
into t1 values(1),(2)'" (expected different error codes on master
and slave)

Now the slave displays this:

Error: "Query caused different errors on master and slave. Error
on master: message format='Duplicate entry '%-.192s' for key %d'
error code=1062 ; Error on slave: actual message='no error', error
code=0. Default database: 'test'. Query: 'insert into t1 values(1),(2)'"
(expected different error codes on master and slave)

(Bug #46697)

Replication: When an error occurred in the generation of the name for a new binary log file, the error was logged but not shown to the user. (Bug #46166)

References: See also Bug #37148, Bug #11748696, Bug #40611, Bug #11750196, Bug #43929, Bug #51019.

Comparisons of aggregate values with TIMESTAMP values were incorrect. (Bug #59330, Bug #11766259)

For DIV expressions, assignment of the result to multiple variables could cause a server crash. (Bug #59241, Bug #11766191)

References: See also Bug #8457.

MIN(year_col) could return an incorrect result in some cases. (Bug #59211, Bug #11766165)

mysqlslap failed to check for a NULL return from mysql_store_result() and crashed trying to process the result set. (Bug #59109, Bug #11766074)

In a subquery, a UNION with no referenced tables (or only a reference to the DUAL virtual table) did not permit an ORDER BY clause. (Bug #58970, Bug #11765950)

Configuring MySQL with -DWITHOUT_PERFSCHEMA_STORAGE_ENGINE=1 caused build failures. (Bug #58953)

Several Valgrind warnings were fixed. (Bug #58948, Bug #59021)

OPTIMIZE TABLE for an InnoDB table could raise an assertion if the operation failed because it had been killed. (Bug #58933, Bug #11765920)

If max_allowed_packet was set larger than 16MB, the server failed to reject too-large packets with “Packet too large” errors. (Bug #58887, Bug #11765878)

A NOT IN predicate with a subquery containing a HAVING clause could retrieve too many rows, when the subquery itself returned NULL. (Bug #58818, Bug #11765815)

EXPLAIN could crash for queries that accessed two derived tables. (Bug #58730)

On Solaris, the MySQL build failed if it was configured with debugging enabled. (Bug #58699)

Issuing EXPLAIN EXTENDED for a query that would use condition pushdown could cause mysqld to crash. (Bug #58553, Bug #11765570)

An assertion could be raised for queries for which the optimizer could choose between Index Merge range access or const ref access methods. (Bug #58456)

If MySQL was built with Visual Studio Express, the project wixca was not built. (Bug #58411)

EXPLAIN could crash for queries that used GROUP_CONCAT(). (Bug #58396)

CMake polluted the source tree by writing installation-related temporary files there. (Bug #58372)

Security context references in sp_head.cc were rewritten for improved DTrace compatibility. (Bug #58350)

The ucs2 character set does not support characters outside the Basic Multilingual Plane (BMP), but converting to ucs2 a string containing such characters did not produce a conversion-failure warning. (Bug #58321)

A Valgrind failure occurred in fn_format when called from archive_discover. (Bug #58205, Bug #11765259)

CMake did not add LINK_LIBRARIES for MYSQL_ADD_PLUGIN for libmysqld. (Bug #58158)

An assertion could be raised if the server was closing a session at the same time the session was being killed by another thread. (Bug #58136)

Condition pushdown optimization could push down conditions with incorrect column references. (Bug #58134, Bug #11765196)

Configuration with maintainer mode enabled resulted in errors when compiling with icc. (Bug #57991, Bug #58871)

An ORDER BY clause was bound to the incorrect substatement when used in UNION context. (Bug #57986)

The BIT_AND() function could return incorrect results when a join returned no matching rows. (Bug #57954)

If the set of values aggregated with AVG(DISTINCT) contained a NULL value, the function result could be incorrect. (Bug #57932)

In rare cases, LIKE expressions failed for an indexed column that used a collation containing contractions. (Bug #57737)

Unnecessary subquery evaluation in contexts such as statement preparation or view creation could cause a server crash. (Bug #57703)

View creation could produce Valgrind warnings. (Bug #57352)

NULL geometry values could cause a crash in Item_func_spatial_collection::fix_length_and_dec. (Bug #57321)

It was possible to compile mysqld with Performance Schema support but with a dummy atomic-operations implementation, which caused a server crash. This problem does not affect binary distributions. It is helpful as a safety measure for users who build MySQL from source. (Bug #56769)

The cp1251 character set did not properly support the Euro sign (0x88). For example, converting a string containing this character to utf8 resulted in '?' rather than the utf8 Euro sign. (Bug #56639)

Some unsigned system variables could be displayed with negative values. (Bug #55794)

CREATE DATABASE and DROP DATABASE caused mysql --one-database to lose track of the statement-filtering context. (Bug #54899)

An assertion could be raised during concurrent execution of DROP DATABASE and REPAIR TABLE if the drop deleted a table's .TMD file at the same time the repair tried to read details from the old file that was just removed.

A problem could also occur when DROP TABLE tried to remove all files belonging to a table at the same time REPAIR TABLE had just deleted the table's .TMD file. (Bug #54486)

After compilation from source, all header files were installed in the same directory, even those that should be installed into subdirectories of the installation include directory. (Bug #51925)

When mysqld printed crash dump information, it incorrectly indicated that some valid pointers were invalid. (Bug #51817)

On Mac OS X, a configuration error caused the preference pane to fail. (Bug #51264)

On FreeBSD, if mysqld was killed with a SIGHUP signal, it could corrupt InnoDB .ibd files. (Bug #51023, Bug #11758773)

An assertion could be raised if –1 was inserted into an AUTO_INCREMENT column by a statement writing more than one row. (Bug #50619, Bug #11758417)

If a client supplied a user name longer than the maximum 16 characters permitted for names stored in the MySQL grant tables, all characters were being considered significant when checking for a match. Historically, only the first 16 characters were used for matching; this behavior was restored. (Bug #49752)

The my_seek() and my_tell() functions ignored the MY_WME flag when they returned an error, which could cause client programs to hang. (Bug #48451)

During assignment of values to system variables, legality checks on the value range occurred too late, preventing proper error checking. (Bug #43233)

On Solaris, time-related functions such as NOW() or SYSDATE() could return a constant value. (Bug #42054)

If the remote server for a FEDERATED table could not be accessed, queries for the INFORMATION_SCHEMA.TABLES table failed. (Bug #35333)

MySQL releases are now built on all platforms using CMake rather than the GNU autotools, so autotools support has been removed. For instructions on building MySQL with CMake, see Section 2.9, “Installing MySQL from Source”. If you are familiar with autotools but not CMake, you might find this transition document helpful: http://forge.mysql.com/wiki/Autotools_to_CMake_Transition_Guide Third-party tools that need to extract the MySQL version number formerly found in configure.in can use the VERSION file. See Section 2.9.6, “MySQL Configuration and Third-Party Tools”.

Support for the IBMDB2I storage engine has been removed. (Bug #58079)

The following words are no longer reserved words the way they are in earlier MySQL 5.5 releases: SLOW, GENERAL, IGNORE_SERVER_IDS, MASTER_HEARTBEAT_PERIOD (Bug #57899)

For an upgrade to MySQL 5.5.7 from a previous release, the server exited if the mysql.proxies_priv table did not exist, making upgrades inconvenient. Now the server treats a missing proxies_priv table as equivalent to an empty table. However, after starting the server, you should still run mysql_upgrade to create the table. (Bug #57551)

The autocommit system variable is enabled by default for all user connections, and the session value can be set for each new connection by setting the init_connect system variable to SET autocommit=0. However, this has no effect for users who have the SUPER privilege.

Now the global autocommit value can be set at server startup, and this value is used to initialize the session value for all new connections, including those for users with the SUPER privilege. The variable is treated as a boolean value so it can be enabled with --autocommit, --autocommit=1, or --enable-autocommit. It can be disabled with --autocommit=0, --skip-autocommit, or --disable-autocommit. (Bug #57316)

The client/server protocol now includes a SERVER_QUERY_WAS_SLOW flag to indicate when a query is slow; that is, when query execution exceeds the value of the long_query_time system variable. (Bug #57058)

The time zone tables available at http://dev.mysql.com/downloads/timezones.html have been updated. These tables can be used on systems such as Windows or HP-UX that do not include zoneinfo files. (Bug #40230)

Changes to replication in MySQL 5.6 make mysqlbinlog output generated by the --base64-output=ALWAYS option unusable, so ALWAYS is now deprecated and will be an invalid option value in MySQL 5.6. This should not be a significant problem because --base64-output values other than AUTO are supposed to be used only for debugging, not for production environments.

References: See also Bug #28760.

A --bind-address option has been added to a number of MySQL client programs: mysql, mysqldump, mysqladmin, mysqlbinlog, mysqlcheck, mysqlimport, and mysqlshow. This is for use on a computer having multiple network interfaces, and enables you to choose which interface is used to connect to the MySQL server.

A corresponding change was made to the mysql_options() C API function, which now has a MYSQL_OPT_BIND option for specifying the interface. The argument is a host name or IP address (specified as a string).

InnoDB Storage Engine: Security Fix: A failed CREATE TABLE statement for an InnoDB table could allocate memory that was never freed. (Bug #56947)

Security Fix: Bug #58005 was fixed.

Security Fix: Bug #57687 was fixed.

Security Fix: Bug #57659 was fixed.

Security Fix: Bug #57477 was fixed.

Security Fix: Bug #57272 was fixed.

Security Fix: Bug #57130 was fixed.

Security Fix: Bug #56814 was fixed.

Security Fix: Bug #55146 and Bug #56287 were fixed.

Security Fix: Bug #54484 was fixed.

Performance: InnoDB Storage Engine: Improved concurrency when several ANALYZE TABLE or SHOW TABLE STATUS statements are run simultaneously for InnoDB tables. (Bug #53046)

Incompatible Change: Previously, tables in the performance_schema database had uppercase names. This was incompatible with the lower_case_table_names system variable, and caused issues when the variable value was changed after installing or upgrading.

Now performance_schema table names are lowercase, so they appear in uniform lettercase regardless of the lower_case_table_names setting. References to these tables in SQL statements should be given in lowercase. This is an incompatible change, but provides compatible behavior across different values of lower_case_table_names.

If you upgrade to MySQL 5.5.8 from an earlier version of MySQL 5.5, be sure to run mysql_upgrade (and restart the server) to change the names of existing performance_schema tables from uppercase to lowercase. If mysql_upgrade does not work, use this procedure:

(Bug #57609)

Incompatible Change: The following changes were made to the performance_schema.threads table for conformance with the implementation in MySQL 5.6:

(Bug #57154)

Incompatible Change: Starvation of FLUSH TABLES WITH READ LOCK statements occurred when there was a constant load of concurrent DML statements in two or more connections. Deadlock occurred when a connection that had some table open through a HANDLER statement tried to update data through a DML statement while another connection tried to execute FLUSH TABLES WITH READ LOCK concurrently.

These problems resulted from the global read lock implementation, which was reimplemented with the following consequences:

(Bug #57006, Bug #11764195, Bug #54673, Bug #11762116)

InnoDB Storage Engine: Values could be truncated in certain INFORMATION_SCHEMA columns, such as REFERENTIAL_CONSTRAINTS.REFERENCED_TABLE_NAME and KEY_COLUMN_USAGE.REFERENCED_TABLE_NAME. (Bug #57960)

InnoDB Storage Engine: For an InnoDB table created with ROW_FORMAT=COMPRESSED or ROW_FORMAT=DYNAMIC, a query using the READ UNCOMMITTED isolation level could cause the server to stop with an assertion error, if BLOB or other large columns that use off-page storage were being inserted at the same time. (Bug #57799)

InnoDB Storage Engine: The server could stop with an assertion error on Windows Vista and Windows 7 systems. (Bug #57720)

InnoDB Storage Engine: A followup fix to bug #54678. TRUNCATE TABLE could still cause a crash (assertion error) in the debug version of the server. (Bug #57700)

InnoDB Storage Engine: If the MySQL Server crashed immediately after creating an InnoDB table, the server could quit with a signal 11 during the subsequent restart. The issue could occur if the server halted after InnoDB created the primary index for the table, but before the index definition was recorded in the MySQL metadata. (Bug #57616)

References: This bug is a regression of Bug #54582.

InnoDB Storage Engine: The InnoDB system tablespace could grow continually for a server under heavy load. (Bug #57611)

InnoDB Storage Engine: Heavy concurrent updates of a BLOB column in an InnoDB table could cause a hang. (Bug #57579)

InnoDB Storage Engine: Turning off the innodb_stats_on_metadata option could prevent the ANALYZE TABLE statement from updating the cardinality statistics of InnoDB tables. (Bug #57252)

InnoDB Storage Engine: A query for an InnoDB table could return the wrong value if a column value was changed to a different case, and the column had a case-insensitive index. (Bug #56680)

InnoDB Storage Engine: An existing InnoDB table could be switched to ROW_FORMAT=COMPRESSED implicitly by a KEY_BLOCK_SIZE clause in an ALTER TABLE statement. Now, the row format is only switched to compressed if there is an explicit ROW_FORMAT=COMPRESSED clause. on the ALTER TABLE statement.

Any valid, nondefault ROW_FORMAT parameter takes precedence over KEY_BLOCK_SIZE when both are specified. KEY_BLOCK_SIZE only enables ROW_FORMAT=COMPRESSED if ROW_FORMAT is not specified on either the CREATE TABLE or ALTER TABLE statement, or is specified as DEFAULT. In case of a conflict between KEY_BLOCK_SIZE and ROW_FORMAT clauses, the KEY_BLOCK_SIZE is ignored if innodb_strict_mode is off, and the statement causes an error if innodb_strict_mode is on. (Bug #56632)

InnoDB Storage Engine: The clause KEY_BLOCK_SIZE=0 is now permitted on CREATE TABLE and ALTER TABLE statements for InnoDB tables, regardless of the setting of innodb_strict_mode. The zero value has the effect of resetting the KEY_BLOCK_SIZE table parameter to its default value, depending on the ROW_FORMAT parameter, as if it had not been specified. That default is 8 if ROW_FORMAT=COMPRESSED. Otherwise, KEY_BLOCK_SIZE is not used or stored with the table parameters.

As a consequence of this fix, ROW_FORMAT=FIXED is not permitted when innodb_strict_mode is enabled. (Bug #56628)

InnoDB Storage Engine: A large number of foreign key declarations could cause the output of the SHOW CREATE STATEMENT statement to be truncated. (Bug #56143)

InnoDB Storage Engine: Clarified the message when a CREATE TABLE statement fails because a foreign key constraint does not have the required indexes. (Bug #16290)

Partitioning: In-place ALTER TABLE operations (that do not involve a table copy) on a partitioned table could leave the table in an unusable state. (Bug #57985)

Partitioning: In debug builds, an INSERT ... ON DUPLICATE KEY UPDATE col_name = 0 statement on an AUTO_INCREMENT column caused the server to crash. (Bug #57890)

Partitioning: Issuing ALTER TABLE ... ADD PRIMARY KEY on a partitioned InnoDB table could cause the MySQL Server to crash. (Bug #57778)

Replication: Concurrent statements using a stored function and a DROP DATABASE statement that caused the same stored function to be dropped could cause statement-based replication to fail. This problem is resolved by making sure that DROP DATABASE takes an exclusive metadata lock on all stored functions and stored procedures that it causes to be dropped. (Bug #57663)

References: See also Bug #30977.

Replication: When STOP SLAVE is issued, the slave SQL thread rolls back the current transaction and stops immediately if the transaction updates only tables which use transactional storage engines. Previously, this occurred even when the transaction contained CREATE TEMPORARY TABLE statements, DROP TEMPORARY TABLE statements, or both, although these statements cannot be rolled back. Because temporary tables persist for the lifetime of a user session (in the case, the replication user), they remain until the slave is stopped or reset. When the transaction is restarted following a subsequent START SLAVE statement, the SQL thread aborts with an error that a temporary table to be created (or dropped) already exists (or does not exist, in the latter case).

Following this fix, if an ongoing transaction contains CREATE TEMPORARY TABLE statements, DROP TEMPORARY TABLE statements, or both, the SQL thread now waits until the transaction ends, then stops. (Bug #56118, Bug #11763416)

Replication: If there exist both a temporary table and a nontemporary table having the same name, updates normally apply only to the temporary table, with the exception of a CREATE TABLE ... SELECT statement that creates a nontemporary table having the same name as an existing temporary table. When such a statement was replicated using the MIXED logging format, and the statement was unsafe for row-based logging, updates were misapplied to the temporary table.

Updates were also applied wrongly when a temporary table that used a transactional storage engine was dropped inside a transaction, followed by updates within the same transaction to a nontemporary table having the same name. (Bug #55478)

References: See also Bug #47899, Bug #55709.

Replication: When making changes to relay log settings using CHANGE MASTER TO, the I/O cache was not cleared. This could result in replication failure when the slave attempted to read stale data from the cache and then stopped with an assertion. (Bug #55263)

Replication: Replication of SET and ENUM columns represented using more than 1 byte (that is, SET columns with more than 8 members and ENUM columns with more than 256 constants) between platforms using different endianness failed when using the row-based format. This was because columns of these types are represented internally using integers, but the internal functions used by MySQL to handle them treated them as strings. (Bug #52131)

References: See also Bug #53528.

Replication: Trying to read from a binary log containing a log event of an invalid type caused the slave to crash. (Bug #38718)

Replication: When replicating the mysql.tables_priv table, the Grantor column was not replicated, and was thus left empty on the slave. (Bug #27606)

Setting the read_only system variable at server startup did not work. (Bug #58669)

mysql_upgrade failed after an upgrade from MySQL 5.1. (Bug #58514)

When configuring the build with -DBUILD_CONFIG=mysql_release and building with Visual Studio Express, the build failed if signtool.exe was not present. (Bug #58313)

With CMake 2.8.3, the -DBUILD_CONFIG=mysql_release option did not work. (Bug #58272)

When configuring the build with -DBUILD_CONFIG=mysql_release on Linux, libaio is required, but the error message if it was missing was uninformative. (Bug #58227)

Use of NAME_CONST() in a HAVING clause caused a server crash. (Bug #58199)

BETWEEN did not use indexes for DATE or DATETIME columns. (Bug #58190)

Memory was allocated in fn_expand() for storing path names, but not freed anywhere. (Bug #58173)

In debug builds, inserting a FLOAT value into a CHAR(0) column could cause a server crash. (Bug #58137)

Failure to create a thread to handle a user connection could cause a server crash. (Bug #58080)

During configuration, ADD_VERSION_INFO in cmake/mysql_version.cmake failed if LINK_FLAGS was modified. (Bug #58074)

The Performance Schema did not count I/O for the binary log file. (Bug #58052)

Several compilation problems were fixed. (Bug #57992, Bug #57993, Bug #57994, Bug #57995, Bug #57996, Bug #57997, Bug #58057)

After creation of a table with two foreign key constraints, the INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS table displayed only one of them. (Bug #57904)

Incorrect error handling raised an assertion if character set conversion wrapped an item that failed. (Bug #57882)

In debug builds, a missing DBUG_RETURN macro in sql/client.c caused mysql to be unable to connect to the server. (Bug #57744)

Clients using a client library older than MySQL 5.5.7 suffered loss of connection after executing mysql_change_user() while connected to a 5.5.7 server. (Bug #57689)

The MySQL-shared RPM package failed to provide the lowercase virtual identifier 'mysql-shared' in the RPM 'Provides' tags (usually used for backward compatibility). (Bug #57596)

SHOW PROCESSLIST displayed non-ASCII characters improperly. (Bug #57306)

Passing a string that was not null-terminated to UpdateXML() or ExtractValue() caused the server to fail with an assertion. (Bug #57279, Bug #11764447)

SET GLOBAL debug could cause a crash on Solaris if the server failed to open the trace file. (Bug #57274)

In debug builds, an assertion could be raised during conversion of strings to floating-point values. (Bug #57203)

If the file_name argument to the --defaults-file or --defaults-extra-file option was not a full path name, it could be interpreted incorrectly in some contexts and cause a server crash. Now the file_name argument is interpreted as relative to the current working directory if given as a relative path name rather than as a full path name. (Bug #57108)

A user with no privileges on a stored routine or the mysql.proc table could discover the routine's existence. (Bug #57061)

Queries executed using the Index Merge access method and a temporary file could return incorrect results. (Bug #56862)

The server could crash inside memcpy() when reading certain Performance Schema tables. (Bug #56761, Bug #58003)

The server could crash as a result of accessing freed memory when populating INFORMATION_SCHEMA.VIEWS if a view could not be opened properly. (Bug #56540)

Valgrind warnings about overlapping memory when double-assigning the same variable were corrected. (Bug #56138)

If a STOP SLAVE statement was issued while the slave SQL thread was executing a statement that invoked the SLEEP() function, both statements hung. (Bug #56096)

OPTIMIZE TABLE for InnoDB tables could raise an assertion. (Bug #55930)

Warnings raised by a trigger were not cleared upon successful completion. Now warnings are cleared if the trigger completes successfully, per the SQL standard. (Bug #55850)

For CMake builds, some parts of the source were unnecessarily compiled twice if the embedded server was built. (Bug #55647)

In debug builds, an assertion could be raised if a send_eof() method was called after an error occurred. (Bug #54812)

Boolean command options caused an error if given with an option value and the loose- option prefix. (Bug #54569)

An error in a stored procedure could leave the session in a different default database. (Bug #54375)

The CMake “wrapper” for configure (configure.pl) did not handle the --with-comment option properly. (Bug #52275)

Grouping by a TIME_TO_SEC() function result could cause a server crash or incorrect results. Grouping by a function returning a BLOB could cause an unexpected “Duplicate entry” error and incorrect result. (Bug #52160)

The find_files() function used by SHOW statements performed redundant and unnecessary memory allocation. (Bug #51208)

The Windows sample option files contained values more appropriate for Linux. (Bug #50021)

A failed RENAME TABLE operation could prevent a FLUSH TABLES WITH READ LOCK from completing. (Bug #47924)

Error messages for several delegate-related initialization error conditions that should not occur were changed to help identify the area of failure and to instruct the user to file a bug report if they do occur. A delegate is a set of internal data structures and algorithms. (Bug #47027)

On file systems with case insensitive file names, and lower_case_table_names=2, the server could crash due to a table definition cache inconsistency. (Bug #46941)

Handling of host name lettercase in GRANT statements was inconsistent. (Bug #36742)

SET NAMES utf8 COLLATE utf8_sinhala_ci did not work. (Bug #26474)

The utf16_bin collation uses code-point order, not byte-by-byte order, as described at Section 9.1.14.1, “Unicode Character Sets”. (The order was byte-by-byte in MySQL 5.5.7.)

MySQL releases now are built using CMake rather than the GNU autotools. Accordingly, the instructions for installing MySQL from source have been updated to discuss how to build MySQL using CMake. See Section 2.9, “Installing MySQL from Source”. If you are familiar with autotools but not CMake, you might find this transition document helpful: http://forge.mysql.com/wiki/Autotools_to_CMake_Transition_Guide

The build process is now similar enough on all platforms, including Windows, that there are no longer sections dedicated to notes for specific platforms.

The default installation layout when compiling from source now matches that used for binary distributions. You will notice these differences for installations from source distributions:

The make_binary_distribution and make_win_bin_dist scripts are now obsolete. To create a binary distribution, use make package.

MySQL now supports pluggable authentication, such that the server uses plugins to authenticate incoming client connections. Client programs load an authentication plugin that interacts properly with the corresponding server plugin.

Pluggable authentication enables two important capabilities, external authentication and proxy users:

Pluggable authentication entails these changes:

Proxy user capability entails these changes:

Due to these changes, the server requires that a new grant table, proxies_priv, be present in the mysql database. If you are upgrading to MySQL 5.5.7 from a previous MySQL release rather than performing a new installation, the server will find that this table is missing and exit during startup with the following message:

Table 'mysql.proxies_priv' doesn't exist

To create the proxies_priv table, start the server with the --skip-grant-tables option to cause it to skip the normal grant table checks, then run mysql_upgrade. For example:

shell> mysqld --skip-grant-tables &
shell> mysql_upgrade

Then stop the server and restart it normally.

You can specify other options on the mysqld command line if necessary. Alternatively, if your installation is configured so that the server normally reads options from an option file, use the --defaults-file option to specify the file (enter each command on a single line):

shell> mysqld --defaults-file=/usr/local/mysql/etc/my.cnf
         --skip-grant-tables &
shell> mysql_upgrade

With the --skip-grant-tables option, the server does no password or privilege checking, so any client can connect and effectively have all privileges. For additional security, use the --skip-networking option as well to prevent remote clients from connecting.

For additional information, consult these references:

Incompatible Change: Previously, if you flushed the logs using FLUSH LOGS or mysqladmin flush-logs and mysqld was writing the error log to a file (for example, if it was started with the --log-error option), it renamed the current log file with the suffix -old, then created a new empty log file. This had the problem that a second log-flushing operation thus caused the original error log file to be lost unless you saved it under a different name. For example, you could use the following commands to save the file:

shell> mysqladmin flush-logs
shell> mv host_name.err-old backup-directory

To avoid the preceding file-loss problem, renaming no longer occurs. The server merely closes and reopens the log file. To rename the file, you can do so manually before flushing. Then flushing the logs reopens a new file with the original file name. For example, you can rename the file and create a new one using the following commands:

shell> mv host_name.err host_name.err-old
shell> mysqladmin flush-logs
shell> mv host_name.err-old backup-directory

(Bug #29751)

References: See also Bug #56821.

The unused and undocumented thread_pool_size system variable was removed. (Bug #57338)

The pstack library was nonfunctional and has been removed, along with the --with-pstack option for configure and the --enable-pstack option for mysqld. (Bug #57210)

Added a new SHOW PROCESSLIST state, Waiting for query cache lock. This indicates that a session is waiting to take the query cache lock while it performs some query cache operation. (Bug #56822)

A new status variable, Handler_read_last, displays the number of requests to read the last key in an index. With ORDER BY, the server issues a first-key request followed by several next-key requests, whereas with ORDER BY DESC, the server issues a last-key request followed by several previous-key requests. (Bug #52312)

Previously, the server supported values of OFF, ON, and FORCE for the --plugin_name=value option format for controlling plugin loading using an option named after the plugin. Such options now support a FORCE_PLUS_PERMANENT value. This value is like FORCE, but in addition prevents the plugin from being unloaded at runtime. If a user attempts to do so with UNINSTALL PLUGIN, an error occurs. See Section 5.1.7.1, “Installing and Uninstalling Plugins”.

In addition, the INFORMATION_SCHEMA.PLUGINS table now has a LOAD_OPTION column that indicates the plugin loading value (OFF, ON, FORCE, or FORCE_PLUS_PERMANENT). See Section 19.14, “The INFORMATION_SCHEMA PLUGINS Table”.

InnoDB Storage Engine: Incompatible Change: Security Fix: Issuing TRUNCATE TABLE and examining the same table's information in the INFORMATION_SCHEMA database at the same time could cause a crash in the debug version of the server.

As a result of this change, InnoDB always uses the fast truncation technique, equivalent to DROP TABLE and CREATE TABLE. It no longer performs a row-by-row delete for tables with parent-child foreign key relationships. TRUNCATE TABLE returns an error for such tables. Modify your SQL to issue DELETE FROM table_name for such tables instead. (Bug #54678)

Security Fix: The server crashed for assignment of values of types other than Geometry to items of type GeometryCollection (MultiPoint, MultiCurve, MultiSurface). Now the server checks the value type and fails with bad geometry value if it detects incorrect parameters. (Bug #55531)

Security Fix: The CONVERT_TZ() function crashed the server when the timezone argument was an empty SET column value. (Bug #55424)

Security Fix: EXPLAIN EXTENDED caused a server crash with some prepared statements. (Bug #54494)

Security Fix: In prepared-statement mode, EXPLAIN for a SELECT from a derived table caused a server crash. (Bug #54488)

Security Fix: The PolyFromWKB() function could crash the server when improper WKB data was passed to the function. (Bug #51875, Bug #11759554, CVE-2010-3840)

Performance: InnoDB Storage Engine: The master InnoDB background thread could sometimes cause transient performance drops due to excessive flushing of modified pages. (Bug #56933)

Incompatible Change: Replication: The behavior of INSERT DELAYED statements when using statement-based replication has changed as follows:

Previously, when using binlog_format=STATEMENT, a warning was issued in the client when executing INSERT DELAYED; now, no warning is issued in such cases.

Previously, when using binlog_format=STATEMENT, INSERT DELAYED was logged as INSERT DELAYED; now, it is logged as an INSERT, without the DELAYED option.

However, when binlog_format=STATEMENT, INSERT DELAYED continues to be executed as INSERT (without the DELAYED option). The behavior of INSERT DELAYED remains unchanged when using binlog_format=ROW: INSERT DELAYED generates no warnings, is executed as INSERT DELAYED, and is logged using the row-based format.

This change also affects binlog_format=MIXED, because INSERT DELAYED is no longer considered unsafe. Now, when the logging format is MIXED, no switch to row-based logging occurs. This means that the statement is logged as a simple INSERT (that is, without the DELAYED option), using the statement-based logging format. (Bug #54579, Bug #11762035)

References: See also Bug #56678, Bug #11763907, Bug #57666. This bug was introduced by Bug #39934, Bug #11749859.

Incompatible Change: HANDLER ... READ statements that invoke stored functions can cause replication errors. Such statements are now disallowed and result in an ER_NOT_SUPPORTED_YET error. (Bug #54920)

Important Change: InnoDB Storage Engine: The server could crash with an assertion, possibly leading to data corruption, while updating the primary key of an InnoDB table containing BLOB or other columns requiring off-page storage. This fix applies to the InnoDB Plugin in MySQL 5.1, and to InnoDB 1.1 in MySQL 5.5. (Bug #55543)

InnoDB Storage Engine: Replication: If the master had innodb_file_per_table=OFF, innodb_file_format=Antelope (and innodb_strict_mode=OFF), or both, certain CREATE TABLE options, such as KEY_BLOCK_SIZE, were ignored. This could permit the master to avoid raising ER_TOO_BIG_ROWSIZE errors.

However, the ignored CREATE TABLE options were still written into the binary log, so that, if the slave had innodb_file_per_table=ON and innodb_file_format=Barracuda, it could encounter an ER_TOO_BIG_ROWSIZE error while executing the record from the log, causing the slave SQL thread to abort and replication to fail.

In the case where the master was running MySQL 5.1 and the slave was MySQL 5.5 (or later), the failure occurred when both master and slave were running with default values for innodb_file_per_table and innodb_file_format. This could cause problems during upgrades.

To address this issue, the default values for innodb_file_per_table and innodb_file_format are reverted to the MySQL 5.1 default values—that is, OFF and Antelope, respectively. (Bug #56318, Bug #11763590)

InnoDB Storage Engine: The server could crash with a high volume of concurrent LOCK TABLES and UNLOCK TABLES statements. (Bug #57345)

InnoDB Storage Engine: InnoDB incorrectly reported an error when a cascading foreign key constraint deleted more than 250 rows. (Bug #57255)

InnoDB Storage Engine: If the server crashed during an ALTER TABLE operation on an InnoDB table, examining the table through SHOW CREATE TABLE or querying the INFORMATION_SCHEMA tables could cause the server to stop with an assertion error. (Bug #56982)

InnoDB Storage Engine: The output from the SHOW ENGINE INNODB STATUS command can now be up to 1MB. Formerly, it was truncated at 64KB. Monitoring applications that parse that output can check whether it exceeds this new, larger limit by testing the Innodb_truncated_status_writes status variable. (Bug #56922)

InnoDB Storage Engine: For debug builds, a SELECT ... FOR UPDATE statement affecting a range of rows in an InnoDB table could cause a server crash. (Bug #56716)

InnoDB Storage Engine: Improved the performance of UPDATE operations on InnoDB tables, when only non-indexed columns are changed. (Bug #56340)

InnoDB Storage Engine: When MySQL was restarted after a crash with the option innodb_force_recovery=6, certain queries against InnoDB tables could fail, depending on WHERE or ORDER BY clauses.

Usually in such a disaster recovery situation, you dump the entire table using a query without these clauses. During advanced troubleshooting, you might use queries with these clauses to diagnose the position of the corrupted data, or to recover data following the corrupted part. (Bug #55832)

InnoDB Storage Engine: The CHECK TABLE command could cause a time-consuming verification of the InnoDB adaptive hash index memory structure. Now this extra checking is only performed in binaries built for debugging. (Bug #55716)

InnoDB Storage Engine: A heavy workload with a large number of threads could cause a crash in the debug version of the server. (Bug #55699)

InnoDB Storage Engine: The server could crash on shutdown, if started with --innodb-use-system-malloc=0. (Bug #55627)

InnoDB Storage Engine: If the server crashed during a RENAME TABLE operation on an InnoDB table, subsequent crash recovery could fail. This problem could also affect an ALTER TABLE statement that caused a rename operation internally. (Bug #55027)

InnoDB Storage Engine: Setting the PACK_KEYS=0 table option for an InnoDB table prevented new indexes from being added to the table. (Bug #54606)

InnoDB Storage Engine: The server could crash when opening an InnoDB table linked through foreign keys to a long chain of child tables. (Bug #54582)

InnoDB Storage Engine: Changed the locking mechanism for the InnoDB data dictionary during ROLLBACK operations, to improve concurrency for REPLACE statements. (Bug #54538)

InnoDB Storage Engine: With multiple buffer pools enabled, InnoDB could flush more data from the buffer pool than necessary, causing extra I/O overhead. (Bug #54346)

InnoDB Storage Engine: InnoDB transactions could be incorrectly committed during recovery, rather than rolled back, if the server crashed and was restarted after performing ALTER TABLE ... ADD PRIMARY KEY on an InnoDB table, or some other operation that involves copying the entire table. (Bug #53756)

InnoDB Storage Engine: InnoDB startup messages now include the start and end times for buffer pool initialization, and the total buffer pool size. (Bug #48026)

Partitioning: An ALTER TABLE statement acting on table partitions that failed while the affected table was locked could cause the server to crash. (Bug #56172)

Partitioning: Multiple-table UPDATE statements involving a partitioned MyISAM table could cause this table to become corrupted. Not all tables affected by the UPDATE needed to be partitioned for this issue to be observed. (Bug #55458)

Partitioning: EXPLAIN PARTITIONS returned bad estimates for range queries on partitioned MyISAM tables. In addition, values in the rows column of EXPLAIN PARTITIONS output did not take partition pruning into account. (Bug #53806, Bug #46754)

Replication: SET PASSWORD caused failure of row-based replication between a MySQL 5.1 master and a MySQL 5.5 slave.

This fix makes it possible to replicate SET PASSWORD correctly, using row-based replication between a master running MySQL 5.1.53 or a later MySQL 5.1 release to a slave running MySQL 5.5.7 or a later MySQL 5.5 release. (Bug #57098)

References: See also Bug #55452, Bug #57357.

Replication: Prepared multiple-row INSERT DELAYED statements were written to the binary log without DELAYED. (Bug #56678, Bug #11763907)

References: This bug is a regression of Bug #54579, Bug #11762035.

Replication: Backticks used to enclose identifiers for savepoints were not preserved in the binary log, which could lead to replication failure when the identifier, stripped of backticks, could be misinterpreted, causing a syntax or other error.

This could cause problems with MySQL application programs making use of generated savepoint IDs. If, for instance, java.sql.Connection.setSavepoint() is called without any parameters, Connector/J automatically generates a savepoint identifier consisting of a string of hexadecimal digits 0-F encased in backtick (`) characters. If such an ID took the form `NeN` (where N represents a string of the decimal digits 0-9, and e is a literal uppercase or lowercase “E” character). Removing the backticks when writing the identifier into the binary log left behind a substring which the slave MySQL server tried to interpret as a floating point number, rather than as an identifier. The resulting syntax error caused loss of replication. (Bug #55961)

References: See also Bug #55962.

Replication: When a slave tried to execute a transaction larger than the slave's value for max_binlog_cache_size, it crashed. This was caused by an assertion that the server should roll back only the statement but not the entire transaction when the error ER_TRANS_CACHE_FULL occurred. However, the slave SQL thread always rolled back the entire transaction whenever any error occurred, regardless of the type of error. (Bug #55375)

Replication: The error message for ER_SLAVE_HEARTBEAT_VALUE_OUT_OF_RANGE was hard coded in English in sql_yacc.yy, so that it could not be translated in errmsg.txt for other languages.

Additionally, this same error message was used for three separate error conditions:

These issues have been addressed as follows:

(Bug #54144)

A buffer overrun could occur when formatting DBL_MAX numbers. (Bug #57209)

COALESCE() in MySQL 5.5 could return a result different from MySQL 5.1 for some arguments. (Bug #57095)

Constant SUBTIME() expressions could return incorrect results. (Bug #57039)

When mysqld was started as a service on Windows and mysqld was writing the error log to a file (for example, if it was started with the --log-error option), the server reassigned the file descriptors of the stdout and stderr streams to the file descriptor of the log file. On Windows, if stdout or stderr is not associated with an output stream, the file descriptor returns a negative value. Previously, this caused the file descriptor reassignment to fail and the server to abort. To avoid this problem on Windows, the server now first assigns the stdout and stderr streams to the log file stream by opening this file. This causes the stdout and stderr file descriptors to be nonzero and the server can successfully reassign them to the file descriptor of the log file. (Bug #56821)

References: This bug is a regression of Bug #29751.

The server could crash inside memcpy() when reading certain Performance Schema tables. (Bug #56761, Bug #58003)

Deadlock could occur for heavily concurrent workloads consisting of a mix of DML, DDL, and FLUSH TABLES statements affecting the same set of tables. (Bug #56715, Bug #56404, Bug #56405)

Memory leaks detected by Valgrind were corrected. (Bug #56709)

On Mac OS X, RENAME TABLE raised an assertion if the lower_case_table_names system variable was 2 and the old table name was specified in uppercase. (Bug #56595)

Performance for certain read-only queries, in particular point_select, had deteriorated compared to previous versions. (Bug #56585)

It was possible to compile mysqld with Performance Schema support but with a dummy atomic-operations implementation, which caused a server crash. This problem does not affect binary distributions. It is helpful as a safety measure for users who build MySQL from source. (Bug #56521)

Executing XA END after an XA transaction was already ended raised an assertion. (Bug #56448)

A SELECT statement could produce a number of rows different from a CREATE TABLE ... SELECT that was supposed to select the same rows. (Bug #56423)

References: This bug is a regression of Bug #38999.

The server crashed if a table maintenance statement such as ANALYZE TABLE or REPAIR TABLE was executed on a MERGE table and opening and locking a child table failed. For example, this could happen if a child table did not exist or if a lock timeout happened while waiting for a conflicting metadata lock to disappear.

As a consequence of this bug fix, it is now possible to use CHECK TABLE for log tables without producing an error. (Bug #56422, Bug #56494)

ALTER TABLE on a MERGE table could result in deadlock with other connections. (Bug #56292, Bug #57002)

Comparison of one STR_TO_DATE() result with another could return incorrect results. (Bug #56271)

The tcmalloc library was missing from binary MySQL packages for Linux. (Bug #56267)

An INSERT DELAYED statement for a MERGE table could cause deadlock if it occurred as part of a transaction or under LOCK TABLES, and there was a concurrent DDL or LOCK TABLES ... WRITE statement that tried to lock one of its underlying tables. (Bug #56251)

In debug builds, the server raised an assertion for DROP DATABASE in installations that had an outdated or corrupted mysql.proc table. For example, this affected mysql_upgrade when run as part of a MySQL 5.1 to 5.5 upgrade. (Bug #56137)

A negative TIME argument to MIN() or MAX() could raise an assertion. (Bug #56120)

The ordering for supplementary characters in the utf8mb4_bin, utf16_bin, and utf32_bin collations was incorrect. (Bug #55980)

On Solaris with gcc 3.4.6, ha_example.so was built with DTrace support even if the server was not, causing plugin loading problems. (Bug #55966)

Short (single-letter) command-line options did not work. (Bug #55873)

If a query specified a DATE or DATETIME value in a format different from 'YYYY-MM-DD HH:MM:SS', a greater-than-or-equal (>=) condition matched only greater-than values in an indexed TIMESTAMP column. (Bug #55779, Bug #50774, Bug #11758558)

If a view was named as the destination table for CREATE TABLE ... SELECT, the server produced a warning whether or not IF NOT EXISTS was used. Now it produces a warning only when IF NOT EXISTS is used, and an error otherwise. (Bug #55777)

CASE expressions with a mix of operands in different character sets sometimes returned incorrect results. (Bug #55744)

After the fix for Bug #39653, the shortest available secondary index was used for full table scans. The primary clustered key was used only if no secondary index could be used. However, when the chosen secondary index includes all columns of the table being scanned, it is better to use the primary index because the amount of data to scan is the same but the primary index is clustered. This is now taken into account. (Bug #55656)

The server entered an infinite loop with high CPU utilization after an error occurred during flushing of the I/O cache. (Bug #55629)

For the Performance Schema, the default number of rwlock classes was increased to 30, and the default number of rwlock and mutex instances was increased to 1 million. These changes were made to account for the volume of data instrumented when the InnoDB storage engine is used (because of the InnoDB buffer pool). (Bug #55576)

If there was an active SELECT statement, an error arising during trigger execution could cause a server crash. (Bug #55421)

Assignment of InnoDB scalar subquery results to a variable resulted in unexpected S locks in READ COMMITTED transation isolation level. (Bug #55382)

In debug builds, FLUSH TABLE table_list WITH READ LOCK for a MERGE table led to an assertion failure if one of the table's children was not present in the list of tables to be flushed. (Bug #55273)

The server could crash during shutdown due to a race condition relating to Performance Schema cleanup. (Bug #55105, Bug #56324)

Queries involving predicates of the form const NOT BETWEEN not_indexed_column AND indexed_column could return incorrect data due to incorrect handling by the range optimizer. (Bug #54802)

With an UPDATE IGNORE statement including a subquery that was evaluated using a temporary table, an error transferring the data from the temporary was ignored, causing an assertion to be raised. (Bug #54543)

A bad DBUG_PRINT statement in fill_schema_schemata() caused server crashes on Solaris. (Bug #54478)

MIN() or MAX() with a subquery argument could raise a debug assertion for debug builds or return incorrect data for nondebug builds. (Bug #54465)

If one session attempted to drop a database containing a table which another session had opened with HANDLER, any instance of ALTER DATABASE, CREATE DATABASE, or DROP DATABASE issued by the latter session produced a deadlock. (Bug #54360)

INFORMATION_SCHEMA plugins with no deinit() method resulted in a memory leak. (Bug #54253)

Row subqueries producing no rows were not handled as UNKNOWN values in row-comparison expressions. (Bug #54190)

Setting SETUP_INSTRUMENTS.TIMER = 'NO' caused TIMER_WAIT values for aggregations to be NULL rather than 0. (Bug #53874)

The max_length metadata value of MEDIUMBLOB types was reported as 1 byte greater than the correct value. (Bug #53296)

If an application using the embedded server called mysql_library_init() a second time after calling mysql_library_init() and mysql_library_end() to start and stop the server, the application crashed when reading option files. (Bug #53251)

The fix for Bug #30234 caused the server to reject the DELETE tbl_name.* ... Access compatibility syntax for multiple-table DELETE statements. (Bug #53034)

The plugin_ftparser.h and plugin_audit.h include files are part of the public API/ABI, but were not tested by the ABI check. (Bug #52821)

An atomic “compare and swap” operation using x86 assembly code (32 bit) could access incorrect data, which would make it work incorrectly and lose the intended atomicity. This in turn caused the MySQL server to work on inconsistent data structures and return incorrect data. That code affected only 32-bit builds; the effect has been observed when icc was used to build binaries. With gcc, no incorrect results have been observed during tests, so this fix is a proactive one. Other compilers do not use this assembly code. (Bug #52419)

In LOAD DATA INFILE, using a SET clause to set a column equal to itself caused a server crash. (Bug #51850)

An assertion could be raised by DELETE on a view that referenced another view which in turn (directly or indirectly) referenced more than one table. (Bug #51099)

In some cases, when the left part of a NOT IN subquery predicate was a row and contained NULL values, the query result was incorrect. (Bug #51070)

CHECKSUM TABLE for Performance Schema tables could cause a server crash due to uninitialized memory reads. (Bug #50557)

For some queries, the optimizer produced incorrect results using the Index Merge access method with InnoDB tables. (Bug #50402)

EXPLAIN produced an incorrect rows value for queries evaluated using an index scan and that included LIMIT, GROUP BY, and ORDER BY on a computed column. (Bug #50394)

mysql_store_result() and mysql_use_result() are not for use with prepared statements and are not intended to be called following mysql_stmt_execute(), but failed to return an error when invoked that way. (Bug #47485)

Using REPAIR TABLE tbl_name USE_FRM on a MERGE table caused the server to crash. (Bug #46339)

If the global and session debug system variables had the same value, the debug trace file could be closed twice, leading to freeing already freed memory and a server crash. (Bug #46165)

If ALTER EVENT failed to load an event after altering it, an assertion could be raised. This could occur, for example, if ALTER EVENT was killed with KILL QUERY. (Bug #44171)

Trailing space removal for utf32 strings was done with non-multibyte-safe code, leading to incorrect result length and assertion failure. (Bug #42511)

A malformed packet sent by the server when the query cache was in use resulted in lost-connection errors. (Bug #42503)

Multiple-statement execution could fail. (Bug #40877)

CREATE TABLE failed if a column referred to in an index definition and foreign key definition had different lettercases in the two definitions. (Bug #39932)

mysqlcheck behaved differently depending on the order in which options were given on the command line. (Bug #35269)

When invoked to display a help message, mysqld also displayed spurious warning or error messages. (Bug #30025)

Incompatible Change: The SHA2() function now returns a character string with the connection character set and collation. Previously, it returned a binary string. This is the same change made for several other encryption functions in MySQL 5.5.3. (Bug #54661)

InnoDB Storage Engine: The mechanism that checks if there is enough space for redo logs was improved, reducing the chance of encountering this message: ERROR: the age of the last checkpoint is x, which exceeds the log group capacity y. (Bug #39168)

InnoDB Storage Engine: Improved performance and scalability on Windows systems, especially for Windows Vista and higher. Re-enabled the use of atomic instructions on Windows systems. For Windows Vista and higher, reduced the number of event handles used. To compile on Windows systems now requires Windows SDK v6.0 or later; either upgrade to Visual Studio 2008 or 2010, or for Visual Studio 2005, install Windows SDK Update for Windows Vista. (Bug #22268)

Previously, MySQL-shared-compat RPMs for Linux contained both the current and previous client library versions for the target platform. Thus, the package contents overlapped with MySQL-shared RPMs, which contain only the current client library version. This can result in problems in two cases:

Now the MySQL-shared-compat RPMs include only older client library versions and no longer include the current version, so that the MySQL-shared and MySQL-shared-compat RPM contents no longer overlap. The MySQL-shared-compat RPM can be installed even if the MySQL-shared RPM is installed, without producing conflicts related to the current library version. The MySQL-shared-compat RPM can be uninstalled when old applications are removed or upgraded to the current library version, without breaking applications that already use the current library version.

If you previously installed the MySQL-shared-compat RPM because you needed both the current and previous libraries, you should install both the MySQL-shared and MySQL-shared-compat RPMs now. (Bug #56150)

Overhead for the Performance Schema interface was reduced. (Bug #55087)

Within stored programs, LIMIT clauses now permit integer-valued routine parameters or local variables as parameters. (Bug #11918)

Code was removed for the following no-longer-supported platforms: NetWare, MS-DOS, VMS, QNX, and 32-bit SPARC.

InnoDB Storage Engine: Security Fix: After changing the values of the innodb_file_format or innodb_file_per_table configuration parameters, DDL statements could cause a server crash. (Bug #55039, CVE-2010-3676)

Security Fix: During evaluation of arguments to extreme-value functions such as LEAST() and GREATEST(), type errors did not propagate properly, causing the server to crash. (Bug #55826, CVE-2010-3833)

Security Fix: The server could crash after materializing a derived table that required a temporary table for grouping. (Bug #55568, CVE-2010-3834)

Security Fix: A user-variable assignment expression that is evaluated in a logical expression context can be precalculated in a temporary table for GROUP BY. However, when the expression value is used after creation of the temporary table, it was re-evaluated, not read from the table, and a server crash resulted. (Bug #55564, CVE-2010-3835)

Security Fix: Joins involving a table with a unique SET column could cause a server crash. (Bug #54575, CVE-2010-3677)

Security Fix: Pre-evaluation of LIKE predicates during view preparation could cause a server crash. (Bug #54568, Bug #11762026, CVE-2010-3836)

Security Fix: Incorrect handling of NULL arguments could lead to a crash for IN() or CASE operations when NULL arguments were either passed explicitly as arguments (for IN()) or implicitly generated by the WITH ROLLUP modifier (for IN() and CASE). (Bug #54477, CVE-2010-3678)

Security Fix: GROUP_CONCAT() and WITH ROLLUP together could cause a server crash. (Bug #54476, CVE-2010-3837)

Security Fix: Queries could cause a server crash if the GREATEST() or LEAST() function had a mixed list of numeric and LONGBLOB arguments, and the result of such a function was processed using an intermediate temporary table. (Bug #54461, CVE-2010-3838)

Security Fix: A malformed argument to the BINLOG statement could result in Valgrind warnings or a server crash. (Bug #54393, CVE-2010-3679)

Security Fix: After ALTER TABLE was used on a temporary transactional table locked by LOCK TABLES, any later attempts to execute LOCK TABLES or UNLOCK TABLES caused a server crash. (Bug #54117)

Security Fix: Use of TEMPORARY InnoDB tables with nullable columns could cause a server crash. (Bug #54044, CVE-2010-3680)

Security Fix: Queries with nested joins could cause an infinite loop in the server when used from stored procedures and prepared statements. (Bug #53544, CVE-2010-3839)

Security Fix: Using EXPLAIN with queries of the form SELECT ... UNION ... ORDER BY (SELECT ... WHERE ...) could cause a server crash. (Bug #52711, CVE-2010-3682)

Security Fix: Bug #49124 was fixed.

Security Fix: Bug #49124 and Bug #11757121 were fixed.

Performance: InnoDB Storage Engine: The setting innodb_change_buffering=all could produce slower performance for some operations than the previous default, innodb_change_buffering=inserts. (Bug #54914)

Performance: InnoDB Storage Engine: An EXPLAIN plan for an InnoDB table could vary greatly in the estimated cost for a BETWEEN clause. (Bug #53761)

Incompatible Change: Replication: As of MySQL 5.5.6, handling of CREATE TABLE IF NOT EXISTS ... SELECT statements has been changed for the case that the destination table already exists:

This change in handling of IF NOT EXISTS results in an incompatibility for statement-based replication from a MySQL 5.1 master with the original behavior and a MySQL 5.5 slave with the new behavior. Suppose that CREATE TABLE IF NOT EXISTS ... SELECT is executed on the master and the destination table exists. The result is that rows are inserted on the master but not on the slave. (Row-based replication does not have this problem.)

To address this issue, statement-based binary logging for CREATE TABLE IF NOT EXISTS ... SELECT is changed in MySQL 5.1 as of 5.1.51:

This change provides forward compatibility for statement-based replication from MySQL 5.1 to 5.5 because when the destination table exists, the rows will be inserted on both the master and slave. To take advantage of this compatibility measure, the 5.1 server must be at least 5.1.51 and the 5.5 server must be at least 5.5.6.

To upgrade an existing 5.1-to-5.5 replication scenario, upgrade the master first to 5.1.51 or higher. Note that this differs from the usual replication upgrade advice of upgrading the slave first.

A workaround for applications that wish to achieve the original effect (rows inserted regardless of whether the destination table exists) is to use CREATE TABLE IF NOT EXISTS and INSERT ... SELECT statements rather than CREATE TABLE IF NOT EXISTS ... SELECT statements.

Along with the change just described, the following related change was made: Previously, if an existing view was named as the destination table for CREATE TABLE IF NOT EXISTS ... SELECT, rows were inserted into the underlying base table and the statement was written to the binary log. As of MySQL 5.1.51 and 5.5.6, nothing is inserted or logged. (Bug #47442, Bug #47132, Bug #48814, Bug #49494)

Incompatible Change: Several changes were made to Performance Schema tables:

(Bug #55416)

Incompatible Change: Handling of warnings and errors during stored program execution was problematic:

(Bug #36185, Bug #5889, Bug #9857, Bug #23032)

Incompatible Change: If the server was started with character_set_server set to utf16, it crashed during full-text stopword initialization. Now the stopword file is loaded and searched using latin1 if character_set_server is ucs2, utf16, or utf32.

If any table was created with FULLTEXT indexes while the server character set was ucs2, utf16, or utf32, it should be repaired using this statement:

REPAIR TABLE tbl_name QUICK;

(Bug #32391)

Important Change: Replication: The LOAD DATA INFILE statement is now considered unsafe for statement-based replication. When using statement-based logging mode, the statement now produces a warning; when using mixed-format logging, the statement is made using the row-based format. (Bug #34283)

InnoDB Storage Engine: An assertion was raised if (1) an InnoDB table was created using CREATE TABLE ... SELECT where the query used an INFORMATION_SCHEMA table and a view existed in the database; or (2) any statement that modified an InnoDB table had a subquery referencing an INFORMATION_SCHEMA table. (Bug #55973)

InnoDB Storage Engine: The InnoDB storage engine was not included in the default installation when using the configure script. (Bug #55547)

InnoDB Storage Engine: For an InnoDB table with an auto-increment column, the server could crash if the first statement that references the table after a server restart is a SHOW CREATE TABLE statement. (Bug #55277)

InnoDB Storage Engine: The mysql_config tool did not output the requirement for the aio library for mysqld-libs. (Bug #55215)

InnoDB Storage Engine: Some memory used for InnoDB asynchronous I/O was not freed at shutdown. (Bug #54764)

InnoDB Storage Engine: Implementation of the 64-bit dulint structure in InnoDB was not optimized for 64-bit processors, resulting in excessive storage and reduced performance. (Bug #54728)

InnoDB Storage Engine: The output from the SHOW ENGINE INNODB STATUS command now includes information about “spin rounds” for RW-locks (both shared and exclusive locks). (Bug #54726)

InnoDB Storage Engine: An ALTER TABLE statement could convert an InnoDB compressed table (with row_format=compressed) back to an uncompressed table (with row_format=compact). (Bug #54679)

InnoDB Storage Engine: InnoDB could issue an incorrect message on startup, if tables were created under the setting innodb_file_per_table=ON. The message was of the form InnoDB: Warning: allocated tablespace n, old maximum was 0. If you encounter this message after upgrading, create an InnoDB table with innodb_file_per_table = ON and restart the server. The message should not be displayed any more. If you continue to encounter this message, or if you get it and haven't used a version without this fix, you might have corruption in your shared tablespace. If so, back up and reload your data. (Bug #54658)

InnoDB Storage Engine: For debug builds, the database server could crash when renaming a table that had active transactions. (Bug #54453)

InnoDB Storage Engine: The server could crash during the recovery phase of startup, if it previously crashed while inserting BLOB or other large columns that use off-page storage into an InnoDB table created with ROW_FORMAT=REDUNDANT or ROW_FORMAT=COMPACT. (Bug #54408)

InnoDB Storage Engine: For an InnoDB table created with ROW_FORMAT=COMPRESSED or ROW_FORMAT=DYNAMIC, a query using the READ UNCOMMITTED isolation level could cause the server to stop with an assertion error, if BLOB or other large columns that use off-page storage were being inserted at the same time. (Bug #54358)

InnoDB Storage Engine: Fast index creation in the InnoDB Plugin could fail, leaving the new secondary index corrupted. (Bug #54330)

InnoDB Storage Engine: If a session executing TRUNCATE TABLE on an InnoDB table was killed during open_tables(), an assertion could be raised. (Bug #53757)

InnoDB Storage Engine: The Lock_time field in the slow query log now reports a larger value, including the time for InnoDB lock waits at the statement level. (Bug #53496)

InnoDB Storage Engine: Misimplementation of the os_fast_mutex_trylock() function in InnoDB resulted in unnecessary blocking and reduced performance. (Bug #53204)

InnoDB Storage Engine: InnoDB could not create tables that used the utf32 character set. (Bug #52199)

InnoDB Storage Engine: Performing large numbers of RENAME TABLE statements caused excessive memory use. (Bug #47991)

Partitioning: With innodb_thread_concurrency = 1, ALTER TABLE ... REORGANIZE PARTITION and SELECT could deadlock. There were unreleased latches in the ALTER TABLE ... REORGANIZE PARTITION thread which were needed by the SELECT thread to be able to continue. (Bug #54747)

Partitioning: An ALTER TABLE ... ADD PARTITION statement run concurrently with a read lock caused spurious ER_TABLE_EXISTS_ERROR and ER_NO_SUCH_TABLE errors on subsequent attempts. (Bug #53676)

References: See also Bug #53770.

Partitioning: UPDATE and INSERT statements affecting partitioned tables performed poorly when using row-based replication. (Bug #52517)

References: This bug is a regression of Bug #39084.

Partitioning: INSERT ON DUPLICATE KEY UPDATE statements performed poorly on tables having many partitions. The handler function for reading a row from a specific index was not optimized in the partitioning handler. (Bug #52455)

Partitioning: ALTER TABLE ... TRUNCATE PARTITION, when called concurrently with transactional DML on the table, was executed immediately and did not wait for the concurrent transaction to release locks. As a result, the ALTER TABLE statement was written into the binary log before the DML statement, which led to replication failures when using row-based logging. (Bug #49907)

References: See also Bug #42643.

Partitioning: When the storage engine used to create a partitioned table was disabled, attempting to drop the table caused the server to crash. (Bug #46086)

Replication: When using the row-based logging format, a failed CREATE TABLE ... SELECT statement was written to the binary log, causing replication to break if the failed statement was later re-run on the master. In such cases, a DROP TABLE ... IF EXIST statement is now logged in the event that a CREATE TABLE ... SELECT fails. (Bug #55625)

Replication: When using the row-based logging format, a SET PASSWORD statement was written to the binary log twice. (Bug #55452)

Replication: When closing temporary tables, after the session connection was already closed, if the writing of the implicit DROP TABLE statement into the binary log failed, it was possible for the resulting error to be mishandled, triggering an assertion. (Bug #55387)

Replication: Executing SHOW BINLOG EVENTS increased the value of max_allowed_packet applying to the session that executed the statement. (Bug #55322)

Replication: Setting binlog_format to ROW, then creating and dropping a temporary table led to an assertion. (Bug #54925)

Replication: When using mixed-format replication, changes made to a nontransactional temporary table within a transaction were not written into the binary log when the transaction was rolled back. This could lead to a failure in replication if the temporary table was used again afterwards. (Bug #54872)

References: See also Bug #53259.

Replication: If binlog_format was explicitly switched from STATEMENT to ROW following the creation of a temporary table, then on disconnection the master failed to write the expected DROP TEMPORARY TABLE statement into the binary log. As a consequence, temporary tables (and their corresponding files) accumulated as this scenario was repeated. (Bug #54842)

References: See also Bug #52616.

Replication: If the SQL thread was started while the I/O thread was performing rotation of the relay log, the two threads could begin to race for the same I/O cache, leading to a server crash. (Bug #54509)

References: See also Bug #50364.

Replication: Two related issues involving temporary tables and transactions were introduced by a fix made in MySQL 5.1.37:

The current fix restores the correct behavior in both of these cases. (Bug #53560)

References: This bug was introduced by Bug #43929.

Replication: The value of binlog_direct_non_transactional_updates had no effect on statements mixing transactional tables and nontransactional tables, or mixing temporary tables and nontransactional tables.

As part of the fix for this issue, updates to temporary tables are now handled as transactional or nontransactional according to their storage engine types. (In effect, the current fix reverts a change made previously as part of the fix for Bug #53259.)

In addition, unsafe mixed statements (that is, statements which access transactional table as well nontransactional or temporary tables, and write to any of them) are now handled as transactional when the statement-based logging format is in use. (Bug #53452)

References: See also Bug #51894.

Replication: A number of statements generated unnecessary warnings as potentially unsafe statements. (Due to the fix for Bug #51894, a temporary table is treated in this context as a transactional table, so that any mixed statement such as t_innodb + t_myisam or t_temp + t_myisam is flagged as unsafe.)

To reduce the number of spurious warnings produced when this happened, some of the criteria used to classify a statements as safe or unsafe have been changed. For more information about handling of mixed statements, see Transactional, nontransactional, and mixed statements. (Bug #53259)

References: See also Bug #53452, Bug #54872.

Replication: When binlog_format=STATEMENT, any statement that is flagged as being unsafe, possibly causing the slave to go out of sync, generates a warning. This warning is written to the server log, the warning count is returned to the client in the server's response, and the warnings are accessible through SHOW WARNINGS.

The current bug affects only the counts for warnings to the client and that are visible through SHOW WARNINGS; it does not affect which warnings are written to the log. The current issue came about because the fix for an earlier issue caused warnings for substatements to be cleared whenever a new substatement was started. However, this suppressed warnings for unsafe statements in some cases. Now, such warnings are no longer cleared. (Bug #50312)

References: This bug was introduced by Bug #36649.

Replication: Replication could break if a transaction involving both transactional and nontransactional tables was rolled back to a savepoint. It broke if a concurrent connection tried to drop a transactional table which was locked after the savepoint was set. This DROP TABLE completed when ROLLBACK TO SAVEPOINT was executed because the lock on the table was dropped by the transaction. When the slave later tried to apply the binary log events, it failed because the table had already been dropped. (Bug #50124)

Replication: When CURRENT_USER() or CURRENT_USER was used to supply the name and host of the affected user or of the definer in any of the statements DROP USER, RENAME USER, GRANT, REVOKE, and ALTER EVENT, the reference to CURRENT_USER() or CURRENT_USER was not expanded when written to the binary log. This resulted in CURRENT_USER() or CURRENT_USER being expanded to the user and host of the slave SQL thread on the slave, thus breaking replication. Now CURRENT_USER() and CURRENT_USER are expanded prior to being written to the binary log in such cases, so that the correct user and host are referenced on both the master and the slave. (Bug #48321)

After an RPM installation, mysqld would be started with the root user, rather than the mysql user. (Bug #56574)

The embedded server raised an assertion when it attempted to load plugins. (Bug #56085)

FORMAT() did not respect the decimal point character if the locale was changed and always returned an ASCII value. (Bug #55912)

CMake produced bad dependencies for the sql/lex_hash.h file during configuration. (Bug #55842)

mysql_upgrade did not handle the --ssl option properly. (Bug #55672)

Using MIN() or MAX() on a column containing the maximum TIME value caused a server crash. (Bug #55648)

Incorrect handling of user variable assignments as subexpressions could lead to incorrect results or server crashes. (Bug #55615)

The default compiler options for Mac OS X 10.5 were set incorrectly. (Bug #55601)

The server was not checking for errors generated during the execution of Item::val_xxx() methods when copying data to a group, order, or distinct temp table's row. (Bug #55580)

ORDER BY clauses that included user-variable expressions could raise a debug assertion. (Bug #55565)

SHOW CREATE TRIGGER took a stronger metadata lock than required. This caused the statement to be blocked unnecessarily. For example, LOCK TABLES ... WRITE in one session blocked SHOW CREATE TRIGGER in another session.

Also, a SHOW CREATE TRIGGER statement issued inside a transaction did not release its metadata locks at the end of statement execution. Consequently, SHOW CREATE TRIGGER was able to block other sessions from accessing the table (for example, using ALTER TABLE). (Bug #55498)

A single-table DELETE ordered by a column that had a hash-type index could raise an assertion or cause a server crash. (Bug #55472)

A call to mysql_library_init() following a call to mysql_library_end() caused a client crash. (Bug #55345)

The -features=no%except option was missing from the build for Solaris/x86. (Bug #55250)

A statement that was aborted by KILL QUERY while it waited on a metadata lock could raise an assertion in debug builds, or send OK to the client instead of ER_QUERY_INTERRUPTED in regular builds. (Bug #55223)

GROUP BY operations used max_sort_length inconsistently. (Bug #55188)

The Windows MSI installer failed during installation to preserve custom settings, such as the configured data directory. (Bug #55169)

InnoDB produced no warning at startup about illegal innodb_file_format_check values. (Bug #55095)

IF() with a subquery argument could raise a debug assertion for debug builds under some circumstances. (Bug #55077)

Building MySQL on Solaris 8 x86 failed when using Sun Studio due to gcc inline assembly code. (Bug #55061)

When upgrading an existing install with an RPM on Linux, the MySQL server might not have been restarted properly. This was due to a naming conflict when upgrading from a community named RPM. Previous installations are now correctly removed, the MySQL initialization script is recreated, and the MySQL server is restarted as normal. (Bug #55015)

The thread_concurrency system variable was unavailable on non-Solaris systems. (Bug #55001)

mysqld_safe contained a syntax error that prevented it from restarting the server. (Bug #54991)

If audit plugins were installed that were interested in MYSQL_AUDIT_GENERAL_CLASS events and the general query log was disabled, failed INSTALL PLUGIN or UNINSTALL PLUGIN statements caused a server crash. (Bug #54989)

Some functions did not calculate their max_length metadata value correctly. (Bug #54916)

A SHOW CREATE TABLE statement issued inside a transaction did not release its metadata locks at the end of statement execution. Consequently, SHOW CREATE TABLE was able to block other sessions from accessing the table (for example, using ALTER TABLE). (Bug #54905)

INFORMATION_SCHEMA.ENGINES and SHOW ENGINES described MyISAM as the default storage engine, but this is not true as of MySQL 5.5.5. (Bug #54832)

The MERGE storage engine tried to use memory mapping on the underlying MyISAM tables even on platforms that do not support it and even when myisam_use_mmap was disabled. This led to a hang for INSERT INTO ... SELECT FROM statements that selected from a MyISAM table into a MERGE table that contained the same MyISAM table. (Bug #54811, Bug #50788)

Incorrect error handling could result in an OPTIMIZE TABLE crash. (Bug #54783)

Performance Schema event collection for a thread could “leak” from one connection to another if the thread was used for one connection, then cached, then reused for another connection. (Bug #54782)

In debug builds, an assertion could be raised when the server tried to send an OK packet to the client after having failed to detect errors during processing of the WHERE condition of an UPDATE statement. (Bug #54734)

In a slave SQL thread or Event Scheduler thread, the SLEEP() function could not sleep more than five seconds. (Bug #54729)

SET sql_select_limit = 0 did not work. (Bug #54682)

Assignments of the PASSWORD() or OLD_PASSWORD() function to a user variable did not preserve the character set of the function return value. (Bug #54668)

A signal-handler redefinition for SIGUSR1 was removed. The redefinition could cause the server to encounter a kernel deadlock on Solaris when there are many active threads. Other POSIX platforms might also be affected. (Bug #54667)

Queries that named view columns in a GROUP BY clause could cause a server crash. (Bug #54515)

The Performance Schema displayed spurious startup error messages when the server was run in bootstrap mode. (Bug #54467)

For distributions built with CMake rather than the GNU autotools, mysql lacked pager support, and some scripts were built without the execute bit set. (Bug #54466, Bug #54129)

The server failed to disregard sort order for some zero-length tuples, leading to an assertion failure. (Bug #54459)

A join with an aggregated function and impossible WHERE condition returned an extra row. (Bug #54416)

Ошибки during processing of WHERE conditions in HANDLER ... READ statements were not detected, so the handler code still tried to send EOF to the client, raising an assertion. (Bug #54401)

If a session tried to drop a database containing a table opened with HANDLER in another session, any DATABASE statement (CREATE, DROP, ALTER) executed by that session produced a deadlock. (Bug #54360)

Deadlocks involving INSERT DELAYED statements were not detected. The server could crash if the delayed handler thread was killed due to a conflicting shared metadata lock. (Bug #54332)

After ALTER TABLE was used on a temporary transactional table locked by LOCK TABLES, any later attempts to execute LOCK TABLES or UNLOCK TABLES caused a server crash. (Bug #54117)

INSERT IGNORE INTO ... SELECT statements could raise a debug assertion. (Bug #54106)

SHOW CREATE EVENT released all metadata locks held by the current transaction. This invalidated any existing savepoints and raised an assertion if ROLLBACK TO SAVEPOINT was executed. (Bug #54105)

A client could supply data in chunks to a prepared statement parameter other than of type TEXT or BLOB using the mysql_stmt_send_long_data() C API function (or COM_STMT_SEND_LONG_DATA command). This led to a crash because other data types are not valid for long data. (Bug #54041)

mysql_secure_installation did not properly identify local accounts and could incorrectly remove nonlocal root accounts. (Bug #54004)

A client with automatic reconnection enabled saw the error message Lost connection to MySQL server during query if the connection was lost between the mysql_stmt_prepare() and mysql_stmt_execute() C API functions. However, mysql_stmt_errno() returned 0, not the corresponding error number 2013. (Bug #53899)

INFORMATION_SCHEMA.COLUMNS reported incorrect precision for BIGINT UNSIGNED columns. (Bug #53814)

The patch for Bug #36569 caused performance regressions and incorrect execution of some UPDATE statements. (Bug #53737, Bug #53742)

Missing Performance Schema tables were not reported in the error log at server startup. (Bug #53617)

mysql_upgrade could incorrectly remove TRIGGER privileges. (Bug #53613)

SHOW ENGINE PERFORMANCE_SCHEMA STATUS underreported the amount of memory allocated by the Performance Schema. (Bug #53566)

Portability problems in SHOW STATUS could lead to incorrect results on some platforms. (Bug #53493)

Builds of MySQL generated a large number of warnings. (Bug #53445)

Performance Schema header files were not installed in the correct directory. (Bug #53255)

The server could crash when processing subqueries with empty results. (Bug #53236)

With lower_case_table_names set to a nonzero value, searches for table or database names in INFORMATION_SCHEMA tables could produce incorrect results. (Bug #53095)

Use of uint in typelib.h caused compilation problems in Windows. This was changed to unsigned int. (Bug #52959)

The mysql-debug.pdb supplied with releases did not match the corresponding mysqld.exe. (Bug #52850)

The PERFORMANCE_SCHEMA database was not correctly created and populated on Windows. (Bug #52809)

The large_pages system variable was tied to the --large-files command-line option, not the --large-pages option. (Bug #52716)

Attempts to access a nonexistent Performance Schema table resulted in a misleading error message. (Bug #52586)

The ABI check for MySQL failed to compile with gcc 4.5. (Bug #52514)

The Performance Schema could enter an infinite loop if required to create a large number of mutex instances. (Bug #52502)

mysql_secure_installation sometimes failed to locate the mysql client. (Bug #52274)

Some queries involving GROUP BY and a function that returned DATE raised a debug assertion. (Bug #52159)

If a symbolic link was used in a file path name, the Performance Schema did not resolve all file I/O events to the same name. (Bug #52134)

PARTITION BY KEY on a utf32 ENUM column raised a debugging assertion. (Bug #52121)

A pending FLUSH TABLES tbl_list WITH READ LOCK statement unnecessarily aborted transactions. (Bug #52117)

FLUSH TABLES WITH READ LOCK in one session and FLUSH TABLES tbl_list WITH READ LOCK in another session were mutually exclusive.

This bug fix involved several changes to the states displayed by SHOW PROCESSLIST:

(Bug #52044)

Reading a ucs2 data file with LOAD DATA INFILE was subject to three problems. 1) Incorrect parsing of the file as ucs2 data, resulting in incorrect length of the parsed string. This is fixed by truncating the invalid trailing bytes (incomplete multibyte characters) when reading from the file. 2) Reads from a proper ucs2 file did not recognize newline characters. This is fixed by first checking whether a byte is a newline (or any other special character) before reading it as a part of a multibyte character. 3) When using user variables to hold column data, the character set of the user variable was set incorrectly to the database charset. This is fixed by setting it to the character set specified in the LOAD DATA INFILE statement, if any. (Bug #51876)

XA START had a race condition that could cause a server crash. (Bug #51855)

The results of some ORDER BY ... DESC queries were sorted incorrectly. (Bug #51431)

Index Merge between three indexes could return incorrect results. (Bug #50389)

MIN() and MAX() returned incorrect results for DATE columns if the set of values included '0000-00-00'. (Bug #49771)

Searches in INFORMATION_SCHEMA tables for rows matching a nonexistent database produced an error instead of an empty query result. (Bug #49542)

DROP DATABASE failed if there was a TEMPORARY table with the same name as a non-TEMPORARY table in the database. (Bug #48067)

An assertion occurred in ha_myisammrg.cc line 1137:

  DBUG_ASSERT(this->file->children_attached);

The problem was found while running RQG tests and the assertion occurred during REPAIR, OPTIMIZE, and ANALYZE operations. (Bug #47633)

The optimization method of the ARCHIVE storage engine did not preserve the .frm file embedded in the .ARZ file when rewriting the .ARZ file for optimization. This meant an ARCHIVE table that had been optimized could not be discovered.

The ARCHIVE engine stores the .frm file in the .ARZ file so it can be transferred from machine to machine without also needing to copy the .frm file. The engine subsequently restores the embedded .frm during discovery. (Bug #45377)

With character_set_connection set to utf16 or utf32, CREATE TABLE t1 AS SELECT HEX() ... caused a server crash. (Bug #45263)

The my_like_range_xxx() functions returned badly formed maximum strings for Asian character sets, which caused problems for storage engines. (Bug #45012)

A debugging assertion could be raised after a write failure to a closed socket. (Bug #42496)

Enumeration plugin variables were subject to a type-casting error, causing inconsistent results between different platforms. (Bug #42144)

Sort-index_merge for join tables other than the first table used excessive memory. (Bug #41660)

DROP TABLE held a lock during unlink() file system operations, causing performance problems if unlink() took a long time. (Bug #41158)

Rows inserted in a table by one session were not immediately visible to another session that queried the table, even if the insert had committed. (Bug #37521)

Statements of the form UPDATE ... WHERE ... ORDER BY used a filesort even when not required. (Bug #36569)

References: See also Bug #53737, Bug #53742.

Reading from a temporary MERGE table, with two nontemporary child MyISAM tables, resulted in the error:

ERROR 1168 (HY000): Unable to open underlying table which is differently 
defined or of non-MyISAM type or doesn't exist

(Bug #36171)

safemalloc was excessively slow under certain conditions and has been removed. The --skip-safemalloc server option has also been removed, and the --with-debug=full configuration option is no different from --with-debug. (Bug #34043)

Threads that were calculating the estimated number of records for a range scan did not respond to the KILL statement. That is, if a range join type is possible (even if not selected by the optimizer as a join type of choice and thus not shown by EXPLAIN), the query in the statistics state (shown by the SHOW PROCESSLIST) did not respond to the KILL statement. (Bug #25421)

Problems in the atomic operations implementation could lead to server crashes. (Bug #22320, Bug #52261)

This is the final release of MySQL 5.5 for which Generic Linux MySQL binary packages built with the icc compiler on x86 and x86_64 will be offered. These were previously produced as an alternative to our main packages built using gcc, as they provided noticeable performance benefits. In recent times the performance differences have diminished and build and runtime problems have surfaced, thus it is no longer viable to continue producing them.

We continue to use the icc compiler to produce our distribution-specific RPM packages on ia64.

InnoDB has been upgraded to version 1.1.1. This version is considered of “early adopter” quality.

InnoDB is now the default storage engine, rather than MyISAM, in the regular and enterprise versions of MySQL. This change has the following consequences:

Follow these steps to ensure a smooth transition when upgrading:

Incompatible Change: All numeric operators and functions on integer, floating-point and DECIMAL values now throw an “out of range” error (ER_DATA_OUT_OF_RANGE) rather than returning an incorrect value or NULL, when the result is out of the supported range for the corresponding data type. See Section 10.2.6, “Out-of-Range and Overflow Handling”. (Bug #8433)

InnoDB Storage Engine: The INFORMATION_SCHEMA.INNODB_TRX table now includes a number of fields that duplicate information from the SHOW ENGINE INNODB STATUS output. You no longer need to parse that output to get complete transaction information. (Bug #53336)

InnoDB Storage Engine: InnoDB stores redo log records in a hash table during recovery. On 64-bit systems, this hash table was 1/8 of the buffer pool size. To reduce memory usage, the dimension of the hash table was reduced to 1/64 of the buffer pool size (or 1/128 on 32-bit systems). (Bug #53122)

Previously, the innodb_file_format_check system variable served a dual purpose. Setting it at server startup would keep InnoDB from starting if any tables used a more recent file format than supported by the current level of InnoDB. If InnoDB could start, the same system variable was set to the “highest” file format value used by any InnoDB table in the database. Thus, its value could change from the value you specified.

Now, checking and recording the file format tag are handled using separate variables. innodb_file_format_check can be set to 1 or 0 at server startup to enable or disable whether InnoDB checks the file format tag in the system tablespace. If the tag is checked and is higher than that supported by the current version of InnoDB, an error occurs and InnoDB does not start. If the tag is not higher, InnoDB sets the value of innodb_file_format_max to the file format tag.

For background information about InnoDB file-format management, see Section 13.4.4, “InnoDB File-Format Management”. (Bug #49792, Bug #53654)

The Rows_examined value in slow query log rows now is nonzero for UPDATE and DELETE statements that modify rows. (Bug #49756)

For events of MYSQL_AUDIT_GENERAL_CLASS, the event subclass was not passed to audit plugins even though the server passed the subclass to the plugin handler. The subclass is now available through the following changes:

The NULL_AUDIT example plugin in the plugin/audit_null directory has been modified to count events of each subclass, based on the event_subclass value. See Section 22.2.4.8, “Writing Audit Plugins”. (Bug #47059)

The deprecated mysql_fix_privilege_tables script has been removed. (Bug #42589)

A new system variable, skip_name_resolve, is set from the value of the --skip-name-resolve server option. This provides a way to determine at runtime whether the server uses name resolution for client connections. (Bug #37168)

Added the SHA2() function, which calculates the SHA-2 family of hash functions (SHA-224, SHA-256, SHA-384, and SHA-512). (Contributed by Bill Karwin) (Bug #13174)

Windows MSI package installers create and set up the data directory that the installed server will use, but now also create a pristine “template” data directory named data under the installation directory. This directory can be useful when the machine will be used to run multiple instances of MySQL: After an installation has been performed using an MSI package, the template data directory can be copied to set up additional MySQL instances. See Section 5.6, “Running Multiple MySQL Instances on One Machine”.

It is now possible to build MySQL on all platforms using CMake instead of the GNU autotools. (Prior to MySQL 5.5.5, CMake support was limited to Windows.) For instructions on using CMake to build MySQL, see Section 2.9, “Installing MySQL from Source”.

Security Fix: The server could crash if there were alternate reads from two indexes on a table using the HANDLER interface. (Bug #54007, CVE-2010-3681)

Security Fix: Bug #53933 was fixed.

Security Fix: Bug #53907 was fixed.

Security Fix: The server failed to check the table name argument of a COM_FIELD_LIST command packet for validity and compliance to acceptable table name standards. This could be exploited to bypass almost all forms of checks for privileges and table-level grants by providing a specially crafted table name argument to COM_FIELD_LIST.

In MySQL 5.0 and above, this permitted an authenticated user with SELECT privileges on one table to obtain the field definitions of any table in all other databases and potentially of other MySQL instances accessible from the server's file system.

Additionally, for MySQL version 5.1 and above, an authenticated user with DELETE or SELECT privileges on one table could delete or read content from any other table in all databases on this server, and potentially of other MySQL instances accessible from the server's file system. (Bug #53371, CVE-2010-1848)

Security Fix: The server was susceptible to a buffer-overflow attack due to a failure to perform bounds checking on the table name argument of a COM_FIELD_LIST command packet. By sending long data for the table name, a buffer is overflown, which could be exploited by an authenticated user to inject malicious code. (Bug #53237, CVE-2010-1850)

Security Fix: LOAD DATA INFILE did not check for SQL errors and sent an OK packet even when errors were already reported. Also, an assert related to client/server protocol checking in debug servers sometimes was raised when it should not have been. (Bug #52512, CVE-2010-3683)

Security Fix: Bug #52357 was fixed.

Security Fix: Bug #52315 was fixed.

Security Fix: Privilege checking for UNINSTALL PLUGIN was incorrect. (Bug #51770, CVE-2010-1621)

Security Fix: The server could be tricked into reading packets indefinitely if it received a packet larger than the maximum size of one packet. (Bug #50974, CVE-2010-1849)

Security Fix: Bug #48157 was fixed.

Performance: InnoDB Storage Engine: Deadlock detection could be a bottleneck in InnoDB processing, if many transactions attempted to update the same row simultaneously. The algorithm has been improved to enhance performance and scalability, in the InnoDB Plugin for MySQL 5.1, and in InnoDB 1.1 for MySQL 5.5. (Bug #49047)

Performance: While looking for the shortest index for a covering index scan, the optimizer did not consider the full row length for a clustered primary key, as in InnoDB. Secondary covering indexes are now preferred, making full table scans less likely. (Bug #39653)

References: See also Bug #55656.

Incompatible Change: TRUNCATE TABLE did not take an exclusive lock on a table if truncation was done by deleting all rows in the table. For InnoDB tables, this could break proper isolation because InnoDB ended up aborting some granted locks when truncating a table. Now an exclusive metadata lock is taken before TRUNCATE TABLE can proceed. This guarantees that no other transaction is using the table.

Incompatible change: Truncation using delete no longer fails if sql_safe_updates is enabled (this was an undocumented side effect). (Bug #42643)

Incompatible Change: After SET TRANSACTION ISOLATION LEVEL to set the isolation level for the next transaction, the session value of the tx_isolation system variable could appear to change to the transaction isolation level after completion of statements within the transaction. Now the current transaction isolation level is now established at transaction start. If there was a SET TRANSACTION ISOLATION LEVEL statement, the value is taken from it. Otherwise, the session tx_isolation value is used. A change in the session value while a transaction is active is still permitted, but no longer affects the current transaction isolation level. This is an incompatible change. A change in the session isolation level made while there is no active transaction overrides a SET TRANSACTION ISOLATION LEVEL statement, if there was any. (Bug #20837)

Important Change: Replication: It was possible to set sql_log_bin with session scope inside a transaction or subquery. (Bug #53437)

Important Change: Replication: When changing binlog_format or binlog_direct_non_transactional_updates, permissions were not checked prior to checking the scope and context of the variable being changed.

As a result of this fix, an error is no longer reported when—in the context of a transaction or a stored function—you try to set a value for a session variable that is the same as its previous value, or for a variable whose scope is global only. (Bug #51277)

Important Change: Replication: When invoked, CHANGE MASTER TO and SET GLOBAL sql_slave_skip_counter now cause information to be written to the error log about the slave's state prior to execution of the statement. For CHANGE MASTER TO, this information includes the previous values of MASTER_HOST, MASTER_PORT, MASTER_LOG_FILE, and MASTER_LOG_POS. For SET GLOBAL sql_slave_skip_counter, this information includes the previous values of RELAY_LOG_FILE, RELAY_LOG_POS, and sql_slave_skip_counter. (Bug #43406, Bug #43407)

Important Change: When using fast ALTER TABLE, different internal ordering of indexes in the MySQL optimizer and the InnoDB storage engine could cause error messages about possibly mixed up .frm files and incorrect index use. (Bug #47622)

InnoDB Storage Engine: Replication: TRUNCATE TABLE performed on a temporary table using the InnoDB storage engine was logged even when using row-based mode. (Bug #51251)

InnoDB Storage Engine: Replication: Reading from a table that used a self-logging storage engine and updating a table that used a transactional engine (such as InnoDB) generated changes that were written to the binary log using statement format which could make slaves diverge. However, when using mixed logging format, such changes should be written to the binary log using row format. (This issue did not occur when reading from tables using a self-logging engine and updating MyISAM tables, as this was already handled by checking for combinations of nontransactional and transactional engines.) Now such statements are classified as unsafe, and in mixed mode, cause a switch to row-based logging. (Bug #49019)

InnoDB Storage Engine: The server could crash with a message InnoDB: Assertion failure in thread nnnn, typically during shutdown on a Windows system. (Bug #53947)

InnoDB Storage Engine: Some combinations of SELECT and SELECT FOR UPDATE statements could fail with errors about locks, or incorrectly release a row lock during a semi-consistent read operation. (Bug #53674)

InnoDB Storage Engine: Adding a unique key on multiple columns, where one of the columns is NULL, could mistakenly report duplicate key errors. (Bug #53290)

InnoDB Storage Engine: Fixed a checksum error reported for compressed tables when the --innodb_checksums option is enabled. Although the message stated that the table was corrupted, the table is actually fine. (Bug #53248)

InnoDB Storage Engine: When reporting a foreign key constraint violation during INSERT, InnoDB could display uninitialized data for the DB_TRX_ID and DB_ROLL_PTR system columns. (Bug #53202)

InnoDB Storage Engine: The values of innodb_buffer_pool_pages_total and innodb_buffer_pool_pages_misc in the information_schema.global_status table could be computed incorrectly. (Bug #52983)

InnoDB Storage Engine: InnoDB page splitting could enter an infinite loop for compressed tables. (Bug #52964)

InnoDB Storage Engine: An overly strict assertion could fail during the purge of delete-marked records in DYNAMIC or COMPRESSED InnoDB tables that contain column prefix indexes. (Bug #52746)

InnoDB Storage Engine: InnoDB attempted to choose off-page storage without ensuring that there was an “off-page storage” flag in the record header. To correct this, in DYNAMIC and COMPRESSED formats, InnoDB stores locally any non-BLOB columns having a maximum length not exceeding 256 bytes. This is because there is no room for the “external storage” flag when the maximum length is 255 bytes or less. This restriction trivially holds in REDUNDANT and COMPACT formats, because there InnoDB always stores locally columns having a length up to local_len = 788 bytes. (Bug #52745)

InnoDB Storage Engine: The server could crash during shutdown, if started with the option --innodb_use_sys_malloc=0. (Bug #52546)

InnoDB Storage Engine: Connections waiting for an InnoDB row lock ignored KILL until the row lock wait ended. Now, KILL during lock wait results in “query interrupted” instead of “lock wait timeout exceeded”. The corresponding transaction is rolled back. (Bug #51920)

InnoDB Storage Engine: InnoDB checks to see whether a row could possibly exceed the maximum size if all columns are fully used. This produced Row size too large errors for some tables that could be created with the built-in InnoDB from older MySQL versions. Now the check is only done when innodb_strict_mode is enabled or if the table is dynamic or compressed. (Bug #50495)

InnoDB Storage Engine: Multi-statement execution could fail with an error about foreign key constraints. This problem could affect calls to mysql_query() and mysql_real_query(), and CALL statements that invoke stored procedures. (Bug #48024)

InnoDB Storage Engine: A mismatch between index information maintained within the .frm files and the corresponding information in the InnoDB system tablespace could produce this error: [ERROR] Index index of table has n columns unique inside InnoDB, but MySQL is asking statistics for m columns. Have you mixed up .frm files from different installations? (Bug #44571)

Partitioning: Replication: Attempting to execute LOAD DATA on a partitioned MyISAM table while using statement-based logging mode caused the master to hang or crash. (Bug #51851)

Partitioning: Replication: The NO_DIR_IN_CREATE server SQL mode was not enforced when defining subpartitions. In certain cases, this could lead to failures on replication slaves. (Bug #42954)

Partitioning: Rows inserted into a table created using a PARTITION BY LIST COLUMNS option referencing multiple columns could be inserted into the wrong partition. (Bug #52815)

Partitioning: Partition pruning on RANGE partitioned tables did not always work correctly; the last partition was not excluded if the range was beyond it (when not using MAXVALUE). Now the last partition is not included if the partitioning function value is not within the range. (Bug #51830)

Partitioning: Attempting to partition a table using a DECIMAL column caused the server to crash; this was not supported and is now specifically not permitted. (Bug #51347)

Partitioning: ALTER TABLE statements that cause table partitions to be renamed or dropped (such as ALTER TABLE ... ADD PARTITION, ALTER TABLE ... DROP PARTITION, and ALTER TABLE ... REORGANIZE PARTITION) — when run concurrently with queries against the INFORMATION_SCHEMA.PARTITIONS table — could fail, cause the affected partitioned tables to become unusable, or both. This was due to the fact that the INFORMATION_SCHEMA database ignored the name lock imposed by the ALTER TABLE statement on the partitions affected. In particular, this led to problems with InnoDB tables, because InnoDB would accept the rename operation, but put it in a background queue, so that subsequent rename operations failed when InnoDB was unable to find the correct partition. Now, INFORMATION_SCHEMA honors name locks imposed by ongoing ALTER TABLE statements that cause partitions to be renamed or dropped. (Bug #50561)

References: See also Bug #47343, Bug #45808.

Partitioning: The insert_id server system variable was not reset following an insert that failed on a partitioned MyISAM table having an AUTO_INCREMENT column. (Bug #50392)

Partitioning: Foreign keys are not supported on partitioned tables. However, it was possible using an ALTER TABLE statement to set a foreign key on a partitioned table; it was also possible to partition a table with a single foreign key. (Bug #50104)

Partitioning: It was possible to execute a CREATE TEMPORARY TABLE tmp LIKE pt statement, where pt is a partitioned table, even though partitioned temporary tables are not permitted. This caused the server to crash. Now a check is performed to prevent such statements from being executed. (Bug #49477)

Partitioning: When attempting to perform DDL on a partitioned table and the table's .par file could not be found, the server returned the inaccurate error message Out of memory; restart server and try again (needed 2 bytes). Now in such cases, the server returns the error Failed to initialize partitions from .par file. (Bug #49161)

Partitioning: GROUP BY queries performed poorly for some partitioned tables. This was due to the block size not being set for partitioned tables, thus the keys per block was not correct, which could cause such queries to be optimized incorrectly. (Bug #48229)

References: See also Bug #37252.

Partitioning: REPAIR TABLE failed for partitioned ARCHIVE tables. (Bug #46565)

Replication: When using unique keys on NULL columns in row-based replication, the slave sometimes chose the wrong row when performing an update. This happened because a table having a unique key on such a column could have multiple rows containing NULL for the column used by the unique key, and the slave merely picked the first row containing NULL in that column. (Bug #53893)

Replication: When a CREATE TEMPORARY TABLE ... SELECT statement was executed within a transaction that updated only transactional engines and was later rolled back (for example, due to a deadlock) the changes—including the creation of the temporary table—were not written to the binary log, which caused subsequent updates to this table to fail on the slave. (Bug #53421)

Replication: When using the statement-based logging format, statements that used CONNECTION_ID() were always kept in the transaction cache; consequently, nontransactional changes that should have been flushed before the transaction were kept in the transaction cache. (Bug #53075)

References: This bug was introduced by Bug #51894.

Replication: In some cases, attempting to update a column with a value of an incompatible type resulted in a mismatch between master and slave because the column value was set to its implicit default value on the master (as expected), but the same column on the slave was set to NULL. (Bug #52868)

Replication: ACK packets in semisynchronous replication were not checked for length and malformed packets could cause a server crash. (Bug #52748)

Replication: When temporary tables were in use, switching the binary logging format from STATEMENT to ROW did not take effect until all temporary tables were dropped. (The existence of temporary tables should prevent switching the format only from ROW to STATEMENT from taking effect, not the reverse.) (Bug #52616)

Replication: A buffer overrun in the handling of DATE column values could cause mysqlbinlog to fail when reading logs containing certain combinations of DML statements on a table having a DATE column followed by dropping the table. (Bug #52202)

Replication: The failure of a REVOKE statement was logged with the wrong error code, causing replication slaves to stop even when the failure was expected on the master. (Bug #51987)

Replication: Issuing any DML on a temporary table temp followed by DROP TEMPORARY TABLE temp, both within the same transaction, caused replication to fail.

The fix introduces a change to statement-based binary logging with respect to temporary tables. Within a transaction, changes to temporary tables are saved to the transaction cache and written to the binary log when the transaction commits. Otherwise, out-of-order logging of events could occur. This means that temporary tables are treated similar to transactional tables for purposes of caching and logging. This affects assessment of statements as safe or unsafe and the associated error message was changed from:

Unsafe statement written to the binary log using statement format
since BINLOG_FORMAT = STATEMENT. Statements that read from both
transactional and non-transactional tables and write to any of them
are unsafe.

To:

Unsafe statement written to the binary log using statement format
since BINLOG_FORMAT = STATEMENT. Statements that read from both
transactional (or a temporary table of any engine type) and
non-transactional tables and write to any of them are unsafe.

(Bug #51894)

References: See also Bug #51291, Bug #53075, Bug #53259, Bug #53452, Bug #54872. This bug was introduced by Bug #46364.

Replication: The internal flag indicating whether a user value was signed or unsigned (unsigned_flag) could sometimes change between the time that the user value was recorded for logging purposes and the time that the value was actually written to the binary log, which could lead to inconsistency. Now unsigned_flag is copied when the user variable value is copied, and the copy of unsigned_flag is then used for logging. (Bug #51426, Bug #11759138)

References: See also Bug #49562, Bug #11757508.

Replication: Enabling binlog_direct_non_transactional_updates causes nontransactional changes to be written to the binary log upon committing the statement. However, even when not enabled, the addition of this variable introduced a number of undesired changes in behavior:

These problems have been handled as follows:

(Bug #51291)

References: This bug was introduced by Bug #46364.

Replication: When using temporary tables, the binary log needs to insert a pseudo-thread ID for threads that are using temporary tables, each time a switch happens between two threads, both of which are using temporary tables. However, if a thread issued a failing statement before exit, its ID was not recorded in the binary log, and this in turn caused the ID for the next thread that tried to do something with a temporary table not to be logged as well. Subsequent replays of the binary log failed with the error Table ... doesn't exist. (Bug #51226)

References: This bug is a regression of Bug #35583.

Replication: If the master was using sql_mode='TRADITIONAL', duplicate key errors were not sent to the slave, which received 0 rather than the expected error code. This caused replication to fail even when such an error was expected. (Bug #51055)

Replication: DDL statements that lock tables (such as ALTER TABLE, CREATE INDEX, and CREATE TRIGGER) caused spurious ER_BINLOG_ROW_MODE_AND_STMT_ENGINE or ER_BINLOG_STMT_MODE_AND_ROW_ENGINE errors, even though they did not insert rows into any tables.

(Bug #50479)

References: This bug was introduced by Bug #39934, Bug #11749859.

Replication: When run with the --database option, mysqlbinlog printed ROLLBACK statements but did not print any corresponding SAVEPOINT statements. (Bug #50407)

Replication: When a CREATE EVENT statement was followed by an additional statement and the statements were executed together as a single statement, the CREATE EVENT statement was padded with “garbage” characters when written to the binary log. This led to a syntax error when the event was read from the log. (Bug #50095)

Replication: When using a nontransactional table on the master with autocommit disabled, no COMMIT was recorded in the binary log following a statement affecting this table. If the slave's copy of the table used a transactional storage engine, the result on the slave was as though a transaction had been started, but never completed. (Bug #49522)

References: See also Bug #29288.

The make_binary_distribution target to make could fail on some platforms because the lines generated were too long for the shell. (Bug #54590)

Inconsistent checking of the relationship between SHOW statements and INFORMATION_SCHEMA queries caused such queries to fail sometimes. (Bug #54422)

A crash occurred if a table that was locked with LOCK TABLES was listed twice in a DROP TABLE statement. (Bug #54282)

ALTER TABLE for views is not legal but did not produce an error. (If you need to rename a view, use RENAME TABLE.) (Bug #53976)

Valgrind warnings resulting from passing incomplete DATETIME values to the TIMESTAMP() function were corrected. (Bug #53942)

Builds of the embedded mysqld failed due to a missing element of the struct NET. (Bug #53908, Bug #53912)

The definition of the MY_INIT macro in my_sys.h included an extraneous semicolon, which could cause compilation failure. (Bug #53906)

Queries that used MIN() or MAX() on indexed columns could be optimized incorrectly. (Bug #53859)

UPDATE on an InnoDB table modifying the same index that was used to satisfy the WHERE condition could trigger a debug assertion under some circumstances. (Bug #53830)

MySQL incorrectly processed ALTER DATABASE `#mysql50#special` UPGRADE DATA DIRECTORY NAME where special was ., .., or a sequence starting with ./ or ../. It used the server data directory (which contains other regular databases) as the database directory. (Bug #53804, CVE-2010-2008)

OPTIMIZE TABLE could be run on a table in use by a transaction in a different session, causing repeatable read to break. (Bug #53798)

InnoDB crashed when replacing duplicates in a table after a fast ALTER TABLE added a unique index. (Bug #53592)

For InnoDB tables, the error handler for a fast CREATE INDEX did not reset the error state of the transaction before attempting to undo a failed operation, resulting in a crash. (Bug #53591)

For single-table DELETE statements that used quick select and index scan simultaneously caused a server crash or assertion failure. (Bug #53450)

Certain path names passed to LOAD_FILE() could cause a server crash. (Bug #53417)

If the completion_type session variable was changed after a stored procedure or prepared statement had been cached, the change had no effect on subsequent executions of the procedure or statement. (Bug #53346)

The AND CHAIN option for COMMIT and ROLLBACK failed to preserve the current transaction isolation level. Setting completion_type to 1 also failed to do so. (Bug #53343)

Incorrect results could be returned for LEFT JOIN of InnoDB tables with an impossible WHERE condition. (Bug #53334)

The Lock_time value in the slow query log was negative for stored routines. (Bug #53191)

Setting the innodb_change_buffering system variable to DEFAULT produced an incorrect result. (Bug #53165)

mysqldump and SELECT ... INTO OUTFILE truncated long BLOB and TEXT values to 766 bytes. (Bug #53088)

On some systems, such as Mac OS X, the sockaddr_in and sockaddr_in6 structures contain a non-standard field (sin_len / sin6_len) that must be set but was not. This resulted in hostname lookup failure. (Bug #52923)

In the debug version of the server, the FreeState() function could in some circumstances be called twice, leading to an assertion failure. (Bug #52884)

Concurrent SHOW COLUMNS statements could cause a server crash. (Bug #52856)

With a non-latin1 ASCII-based current character set, the server inappropriately converted DATETIME values to strings. This resulted in the optimizer not using indexes on such columns. (Bug #52849)

mysqld_safe set plugin_dir using a hardcoded default path name rather than a path depending on basedir. (Bug #52737)

Semi-consistent read was implemented for InnoDB to address Bug #3300. Semi-consistent reads do not block when a nonmatching record is already locked by some other transaction. If the record is not locked, a lock is acquired, but is released if the record does not match the WHERE condition. However, semi-consistent read was attempted even for UPDATE statements having a WHERE condition of the form pk_col1=constant1, ..., pk_colN=constantN. Some code failed that was designed with the assumption that semi-consistent read would be only attempted on table scans. (Bug #52663)

Setting @@GLOBAL.debug to an empty string failed to clear the current debug settings. (Bug #52629)

SHOW CREATE TABLE was blocked if the table was write locked by another session. (Bug #52593)

The length and max_length metadata values were incorrect for columns with the TEXT family of data types that used multibyte character sets. This bug was introduced in MySQL 5.5.3. (Bug #52520)

mysql_upgrade attempted to work with stored routines before they were available. (Bug #52444)

The check_table_is_closed() debugging function did not protect access to the MyISAM open tables list, with the result that server crashes could occur during table drop or rename operations. (Bug #52432)

Spurious duplicate-key errors occurred for multiple-column indexes on BINARY columns. (Bug #52430)

EXPLAIN EXTENDED crashed trying to resolve references to freed temporary table columns for GROUP_CONCAT() ORDER BY arguments. (Bug #52397)

During MySQL server installation using the MSI package on Windows, the default-character-set option would be included in the default configuration template file. This caused the MySQL server to fail to start properly. (Bug #52380)

Two sessions trying to set the global event_scheduler system variable to OFF resulted in one of them hanging waiting for the event scheduler to stop. (Bug #52367)

There was a race condition between flags used for signaling that a query was killed, which led to error-reporting and lock-acquisition problems. (Bug #52356)

For a concurrent load of 16 or more connections containing many LOCK TABLES WRITE statements for the same table, server throughput was significantly lower for MySQL 5.5.3 and 5.5.4 than for earlier versions (10%–40% lower depending on concurrency). (Bug #52289)

Operations on geometry data types failed on some systems for builds compiled with Sun Studio. (Bug #52208)

The optimizer could attempt to evaluate the WHERE clause before any rows had been read, resulting in a server crash. (Bug #52177)

Cast operations on NULL DECIMAL values could cause server crashes or Valgrind warnings. (Bug #52168)

An assertion was raised as a result of a NULL string being passed to the dtoa code. (Bug #52165)

A memory leak occurred due to missing deallocation of the comparators array (a member of the Arg_comparator class). (Bug #52124)

For debug builds, creating a view containing a subquery that might require collation adjustment caused an assertion to be raised. For example, this could occur if some items had different collations but the result collation could be adjusted to the one of them. (Bug #52120)

Aggregate functions could incorrectly return NULL in outer join queries. (Bug #52051)

For outer joins, the optimizer could fail to properly calculate table dependencies. (Bug #52005)

A COUNT(DISTINCT) query on a view could cause a server crash. (Bug #51980)

For LDML-defined collations, some data structures were not initialized properly to enable UPPER() and LOWER() to work correctly. (Bug #51976)

On Windows, LOAD_FILE() could cause a crash for some pathnames. (Bug #51893)

Invalid memory reads occurred for HANDLER ... READ NEXT after a failed HANDLER ... READ FIRST. (Bug #51877)

After TRUNCATE TABLE of a MyISAM table, subsequent queries could crash the server if myisam_use_mmap was enabled. (Bug #51868)

If myisam_sort_buffer_size was set to a small value, table repair for MyISAM tables with FULLTEXT indexes could crash the server. (Bug #51866)

Stored routine DDL statements were written to the binary log using statement-based format regardless of the current logging format. (Bug #51839)

A problem with equality propagation optimization for prepared statements and stored procedures caused a server crash upon re-execution of the prepared statement or stored procedure. (Bug #51650)

References: See also Bug #8115, Bug #8849.

The optimizer performed an incorrect join type when COALESCE() appeared within an IN() operation. (Bug #51598)

Locking involving the LOCK_plugin, LOCK_global_system_variables, and LOCK_status mutexes could deadlock. (Bug #51591)

Executing a LOAD XML INFILE statement could sometimes lead to a server crash. (Bug #51571)

The server crashed when the optimizer attempted to determine constant tables but a table storage engine did not support exact record count. (Bug #51494)

The server could crash populating the INFORMATION_SCHEMA.PROCESSLIST table due to lack of mutex protection. (Bug #51377)

Use of HANDLER statements with tables that had spatial indexes caused a server crash. (Bug #51357)

With an XA transaction active, SET autocommit = 1 could cause side effects such as memory corruption or a server crash. (Bug #51342)

Corrupt MyISAM tables were automatically repaired even when myisam_recover_options was set to OFF. (Bug #51327)

Following a bulk insert into a MyISAM table, if MyISAM failed to build indexes using repair by sort, data file corruption could occur. (Bug #51307)

CHECKSUM TABLE could compute the checksum for BIT columns incorrectly. (Bug #51304)

ALTER TABLE on InnoDB tables (including partitioned tables) acquired exclusive locks on rows of the table being altered. If there was a concurrent transaction that did locking reads from this table, this sometimes led to a deadlock that was not detected by the metadata lock subsystem or by InnoDB (and was reported only after exceeding innodb_lock_wait_timeout). (Bug #51263)

A HAVING clause on a joined table in some cases failed to eliminate rows which should have been excluded from the result set. (Bug #51242)

Two sessions trying to set the global event_scheduler system variable to different values could deadlock. (Bug #51160)

InnoDB fast index creation could incorrectly use a table copy in some cases. (Bug #50946)

The Loose Index Scan optimization method assumed that it could depend on the partitioning engine to maintain interval endpoint information, as if it were a storage engine. (Bug #50939)

The type inference used for view columns caused some columns in views to be handled as the wrong type, as compared to the same columns in base tables. DATE columns in base tables were treated as TIME columns in views, and base table TIME columns as view DATETIME columns. (Bug #50918)

A syntactically invalid trigger could cause the server to crash when trying to list triggers. (Bug #50755)

Previously, the server held a global mutex while performing file operations such as deleting an .frm or data file, or reading index statistics from a data file. Now the mutex is not held for these operations. Instead, the server uses metadata locks. (Bug #50589, Bug #51557, Bug #49463)

User-defined variables of type REAL that contained NULL were handled improperly when assigned to a column of another type. (Bug #50511)

Setting --secure-file-priv to the empty string left the value unaffected. (Bug #50373)

Calculation of intervals for Event Scheduler events was not portable. (Bug #50087)

The YEAR values 2000 and 0000 could be treated as equal. (Bug #49910)

Performing a single in-place ALTER TABLE containing ADD INDEX and DROP INDEX options that used the same index name could result in a corrupt table definition file. Now such ALTER TABLE statements are no longer performed in place. (Bug #49838)

mysql_upgrade did not detect when CSV log tables incorrectly contained columns that could be NULL. Now these columns are altered to be NOT NULL. (Bug #49823)

support-files/mysql.spec.sh had unnecessary Perl dependencies. (Bug #49723)

Selecting from INFORMATION_SCHEMA.ROUTINES or INFORMATION_SCHEMA.PARAMETERS resulted in a memory leak. (Bug #48729)

In MySQL 5.1, READ COMMITTED was changed to use less locking due to the availability of row-based binary logging (see the Note under READ COMMITTED at Section 12.3.6, “SET TRANSACTION Синтаксис”). However, READ UNCOMMITTED did not have the same change, so it was using more locks than the higher isolation level, which is unexpected. This was changed so that READ UNCOMMITTED now also uses the lesser amount of locking and has the same restrictions for binary logging. (Bug #48607)

On Intel x86 machines, the optimizer could choose different execution plans for a query depending on the compiler version and optimization flags used to build the server binary. (Bug #48537)

A trigger could change the behavior of assigning NULL to a NOT NULL column. (Bug #48525)

The server crashed when it could not determine the best execution plan for queries involving outer joins with nondeterministic ON clauses such as the ones containing the RAND() function, a user-defined function, or a NOT DETERMINISTIC stored function. (Bug #48483)

EXPLAIN could cause a server crash for some queries with subqueries. (Bug #48419)

The MERGE engine failed to open a child table from a different database if the child table or database name contained characters that were subject to table name to file name encoding.

Further, the MERGE engine did not properly open a child table from the same database if the child table name contained characters such as '/', or '#'. (Bug #48265)

On Windows, the server failed to find a description for Event ID 100. (Bug #48042)

A query that read from a derived table (of the form SELECT ... FROM (SELECT ...)) produced incorrect results when the following conditions were present:

(Bug #47904)

The optimization to read MIN() or MAX() values from an index did not properly handle comparisons with NULL values. This could produce incorrect results for MIN() or MAX()when the WHERE clause tested a NOT NULL column for NULL. (Bug #47762)

Killing a query during the optimization phase of a subquery could cause a server crash. (Bug #47761)

Using REPLACE to update a previously inserted negative value in an AUTO_INCREMENT coumn of an InnoDB table caused the table auto-increment value to be updated to 2147483647. (Bug #47720)

The query shown by EXPLAIN EXTENDED plus SHOW WARNINGS could produce results different from the original query. (Bug #47669)

MyISAM could write uninitialized data to new index pages. Now zeros are written to unused bytes in the pages. (Bug #47598)

OPTIMIZE TABLE for an InnoDB table could raise an assertion if another session issued a concurrent DROP TABLE. (Bug #47459)

For updates to InnoDB tables, TIMESTAMP columns could be updated even when no values actually changed. (Bug #47453)

Setting myisam_repair_threads larger than 1 could result in the cardinality for all indexes of a MyISAM table being set to 1 after parallel index repair. (Bug #47444)

mysqld_safe did not always pass --open-files-limit through to mysqld. mysqld_safe did not treat dashes and underscores as equivalent in option names. (Bug #47095)

When the transaction isolation level was REPEATABLE READ and binary logging used statement or mixed format, SELECT statements with subqueries referencing InnoDB tables unnecessarily acquired shared locks on rows in these tables. (Bug #46947)

In debug builds, if the listed columns in the view definition of the table used in an INSERT ... SELECT statement mismatched, an assertion was raised in the query cache invalidation code following the failing statement. (Bug #46615)

For the COMMIT and ROLLBACK statements, the AND CHAIN and RELEASE modifiers should be mutually exclusive, but the parser permitted both to be specified. (Bug #46527)

If the server is started with --skip-grant-tables, plugin loading and unloading should be prohibited, but the server failed to reject INSTALL PLUGIN and UNINSTALL PLUGIN statements. (Bug #46261)

gcc 4.4.0 could fail to compile dtoa.c. (Bug #45882)

ALTER TABLE ... ADD COLUMN for a table with multiple foreign keys caused a server crash. (Bug #45052)

Manual pages for a few little-used programs were missing from RPM packages. (Bug #44370)

Using an initial command with mysql_options(..., MYSQL_INIT_COMMAND, ...) that generated multiple result sets (such as a stored procedure or a multi-statement command) left the connection unusable. (Bug #42373)

The server could crash with an out of memory error when trying to parse a query that was too long to fit in memory. Now the parser rejects such queries with an ER_OUT_OF_RESOURCES error. (Bug #42064)

InnoDB could fail to create a unique index on NULL columns. (Bug #41904)

For a query that selected from a view and used an alias for the view, the metadata used the alias name rather than the view name in the MYSQL_FIELD.table member. (Bug #41788)

mysql_upgrade did not create temporary files properly. (Bug #41057)

It was possible for DROP TABLE of one MyISAM table to remove the data and index files of a different MyISAM table. (Bug #40980)

If the arguments to a CONCAT() call included a local routine variable, selecting the return value into a user variable could produce an incorrect result. (Bug #40625)

Column names displayed from the PARTITION_EXPRESSION column of the INFORMATION_SCHEMA.PARTITIONS table did not include escape characters as necessary. (Bug #39338)

When SET TRANSACTION ISOLATION LEVEL was used to set the isolation level for the next transaction, the level could persist for subsequent transactions. (Bug #39170)

When using UNINSTALL PLUGIN to remove a loaded plugin, open tables and connections caused mysqld to hang until the open connections had been closed. (Bug #39053)

Valgrind warnings in the InnoDB compare_record() function were corrected. (Bug #38999)

The optimizer sometimes used filesort for ORDER BY when it should have used an index. (Bug #38745)

Setting the session value of the debug system variable also set the global value. (Bug #38054)

Accessing a MERGE table with an empty underlying table list incorrectly resulted in a “wrong index” error message rather than “end of file.” (Bug #35274)

The test for readline during configuration failed when trying to build MySQL in a directory other than the source tree root. (Bug #35250)

mysqld could fail during execution when using SSL. (Bug #34236)

A query on a FEDERATED table in which the data was ordered by a TEXT column returned incorrect results. For example, a query such as the following produced incorrect results if column column1 was a TEXT column:

SELECT * FROM table1 ORDER BY column1;

(Bug #32426)

MySQL Makefiles relied on GNU extensions. (Bug #30708)

The parser allocated too much memory for a query string containing multiple statements. (Bug #27863)

The behavior of the RPM installation for both new installations and upgrade installations has changed.

During a new installation, the server boot scripts are installed, but the MySQL server is not started at the end of the installation, since the status of the system during an unattended installation is not known.

During an upgrade installation using the RPM packages, if the server is running when the upgrade occurs, the server is stopped, the upgrade occurs, and server is restarted. If the server is not already running when the RPM upgrade occurs, the server is not started at the end of the installation.

The boot scripts for MySQL are installed in the appropriate directories in /etc, so the MySQL server will be restarted automatically at the next machine reboot. (Bug #27072)

ROW_COUNT() returned a meaningful value only for some DML statements. Now it returns a value as follows:

(Bug #21818)

debuginfo RPM packages are no longer being built or published.

InnoDB has been upgraded to version 1.1. This version is considered of Beta quality.

For information about InnoDB features, see Section 13.4, “New Features of InnoDB 1.1”. For general information about using InnoDB in MySQL, see Section 13.3, “The InnoDB Storage Engine”.

InnoDB Storage Engine: InnoDB now has a innodb_use_native_aio system variable that can be disabled at startup if there is a problem with the asynchronous I/O subsystem in the OS. This variable applies to Linux systems only, where the MySQL server now has a dependency on the libaio library.

Performance: InnoDB Storage Engine: The redo scan during InnoDB recovery used excessive CPU. The efficiency of this scan was improved, significantly speeding up crash recovery. (Bug #49535, Bug #29847)

Performance: InnoDB Storage Engine: InnoDB page-freeing operations were made faster for compressed blocks, speeding up ALTER TABLE, DROP TABLE, and other operations on compressed tables that free compressed blocks. One symptom of the older behavior could be 100% CPU use during these operations. (Bug #35077)

InnoDB Storage Engine: The AIX implementation of readdir_r() caused InnoDB errors. (Bug #50691)

InnoDB Storage Engine: The limit of 1023 concurrent data-modifying transactions has been raised. The limit is now 128 × 1023 concurrent transactions that generate undo records. You can remove any workarounds that require changing the proper structure of your transactions, such as committing more frequently or delaying DML operations to the end of a transaction. See Section 13.4.7.19, “Better Scalability with Multiple Rollback Segments”. (Bug #26590)

A unique index on a column prefix could not be upgraded to a primary index even if there was no primary index already defined. (Bug #51378)

InnoDB did not reset table AUTO_INCREMENT values to the last used values after a server restart. (Bug #49032)

When using the EXAMPLE storage engine, when the engine had been built as a plugin (instead of built in), and DTrace probes had been enabled during the build, loading the storage engine library failed due to a missing object table entry.

MySQL Server now includes the Performance Schema, a feature for monitoring server execution at a low level. The implementation uses the PERFORMANCE_SCHEMA storage engine and the performance_schema database. The Performance Schema focuses primarily on performance data. This differs from INFORMATION_SCHEMA, which serves for inspection of metadata. For more information, see Глава 20, MySQL Performance Schema.

Performance Schema support is included in binary MySQL distributions but is disabled by default. To enable it, start the server with the --performance_schema option.

To create the performance_schema database if you are upgrading from an earlier release, run mysql_upgrade and restart the server. See Section 4.4.7, “mysql_upgrade — Check Tables for MySQL Upgrade”.

This release includes InnoDB 1.0.6. This version is considered of Release Candidate (RC) quality.

Performance: The performance of internal functions that trim multiple spaces from strings when comparing them has been improved. (Bug #14637)

Incompatible Change: CREATE VIEW and DROP VIEW now are prohibited while a LOCK TABLES statement is in effect. (Bug #56571)

Incompatible Change: The following obsolete constructs have been removed. Where alternatives are shown, applications should be updated to use them.

(Bug #48048)

References: See also Bug #47974, Bug #56408.

Incompatible Change: Aliases for wildcards (as in SELECT t.* AS 'alias' FROM t) are no longer accepted and result in an error. Previously, such aliases were ignored silently. (Bug #27249)

Incompatible Change: Implicit conversion of a number or temporal value to string now produces a value that has a character set and collation determined by the character_set_connection and collation_connection system variables. (These variables commonly are set with SET NAMES. For information about connection character sets, see Section 9.1.4, “Connection Character Sets and Collations”.)

This change means that such a conversion results in a character (nonbinary) string (a CHAR, VARCHAR, or LONGTEXT value), except when the connection character set is set to binary. In that case, the conversion result is a binary string (a BINARY, VARBINARY, or LONGBLOB value).

Previously, an implicit conversion always produced a binary string, regardless of the connection character set. Such implicit conversions to string typically occur for functions that are passed numeric or temporal values when string values are more usual, and thus could have effects beyond the type of the converted value. Consider the expression CONCAT(1, 'abc'). The numeric argument 1 was converted to the binary string '1' and the concatenation of that value with the nonbinary string 'abc' produced the binary string '1abc'.

This change in conversion behavior affects several functions that expect string arguments because a numeric or temporal argument converted to a string now results in a character rather than binary string argument:

These functions remain unaffected:

Encryption and compression functions that expect string arguments and previously returned binary strings are affected depending on the content of the return value:

The INET_NTOA() return value contains only ASCII characters, and this function now returns a character string with the connection character set and collation rather than a binary string.

Incompatible Change: Several changes were made to processing of server system variables and command-line options to make their treatment more consistent.

General changes: