E.193.1. Migration to Version 7.4.6

A dump/restore is not required for those running 7.4.X.

E.193.2. Changes

• Repair possible failure to update hint bits on disk

  Under rare circumstances this oversight could lead to "could not access transaction status" failures, which qualifies it as a potential-data-loss bug.

• Ensure that hashed outer join does not miss tuples

  Very large left joins using a hash join plan could fail to output unmatched left-side rows given just the right data distribution.

• Disallow running pg_ctl as root

  This is to guard against any possible security issues.

• Avoid using temp files in /tmp in make_oidjoins_check

  This has been reported as a security issue, though it's hardly worthy of concern since there is no reason for non-developers to use this script anyway.

• Prevent forced backend shutdown from re-emitting prior command result

  In rare cases, a client might think that its last command had succeeded when it really had been aborted by forced database shutdown.

• Repair bug in pg_stat_get_backend_idset

  This could lead to misbehavior in some of the system-statistics views.

• Fix small memory leak in postmaster

• Fix "expected both swapped tables to have TOAST tables" bug

  This could arise in cases such as CLUSTER after ALTER TABLE DROP COLUMN.

• Prevent pg_ctl restart from adding -D multiple times

• Fix problem with NULL values in GiST indexes

• :: is no longer interpreted as a variable in an ECPG prepare statement