MongoCursor::explain
(PECL mongo >=0.9.2)
MongoCursor::explain — Return an explanation of the query, often useful for optimization and debugging
Description
public array MongoCursor::explain
( void
)
Parameters
This function has no parameters.
Return Values
Returns an explanation of the query.
Examples
Example #1 MongoCursor::explain() example
<?php
$cursor = $collection->find(array("x"=>1), array("y"));
$cursor->sort(array("z" => 1))->limit(4)->skip(5);
var_dump($cursor->explain());
?>
The above example will output something similar to:
array(8) {
["cursor"]=>
string(15) "BtreeCursor x_1"
["startKey"]=>
array(1) {
["x"]=>
int(1)
}
["endKey"]=>
array(1) {
["x"]=>
int(1)
}
["nscanned"]=>
float(4)
["n"]=>
int(4)
["scanAndOrder"]=>
int(1)
["millis"]=>
int(3)
["allPlans"]=>
array(2) {
[0]=>
array(3) {
["cursor"]=>
string(15) "BtreeCursor x_1"
["startKey"]=>
array(1) {
["x"]=>
int(1)
}
["endKey"]=>
array(1) {
["x"]=>
int(1)
}
}
[1]=>
array(3) {
["cursor"]=>
string(11) "BasicCursor"
["startKey"]=>
array(0) {
}
["endKey"]=>
array(0) {
}
}
}
}
Errors/Exceptions
Throws MongoConnectionException if it cannot reach the database.
See Also
MongoDB core docs on » explain.
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения для работы с базами данных
- Расширения для работы с базами данных отдельных производителей
- MongoDB
- Базовые классы
- Функция MongoCursor::addOption() - Adds a top-level key/value pair to a query
- Функция MongoCursor::awaitData() - Sets whether this cursor will wait for a while for a tailable cursor to return more data
- Функция MongoCursor::batchSize() - Limits the number of elements returned in one batch.
- Функция MongoCursor::__construct() - Create a new cursor
- Функция MongoCursor::count() - Counts the number of results for this query
- Функция MongoCursor::current() - Returns the current element
- Функция MongoCursor::dead() - Checks if there are documents that have not been sent yet from the database for this cursor
- Функция MongoCursor::doQuery() - Execute the query.
- Функция MongoCursor::explain() - Return an explanation of the query, often useful for optimization and debugging
- Функция MongoCursor::fields() - Sets the fields for a query
- Функция MongoCursor::getNext() - Return the next object to which this cursor points, and advance the cursor
- Функция MongoCursor::getReadPreference() - Get the read preference for this query
- Функция MongoCursor::hasNext() - Checks if there are any more elements in this cursor
- Функция MongoCursor::hint() - Gives the database a hint about the query
- Функция MongoCursor::immortal() - Sets whether this cursor will timeout
- Функция MongoCursor::info() - Gets the query, fields, limit, and skip for this cursor
- Функция MongoCursor::key() - Returns the current result's _id
- Функция MongoCursor::limit() - Limits the number of results returned
- Функция MongoCursor::maxTimeMS() - Sets a server-side timeout for this query
- Функция MongoCursor::next() - Advances the cursor to the next result
- Функция MongoCursor::partial() - If this query should fetch partial results from mongos if a shard is down
- Функция MongoCursor::reset() - Clears the cursor
- Функция MongoCursor::rewind() - Returns the cursor to the beginning of the result set
- Функция MongoCursor::setFlag() - Sets arbitrary flags in case there is no method available the specific flag
- Функция MongoCursor::setReadPreference() - Set the read preference for this query
- Функция MongoCursor::skip() - Skips a number of results
- Функция MongoCursor::slaveOkay() - Sets whether this query can be done on a secondary [deprecated]
- Функция MongoCursor::snapshot() - Use snapshot mode for the query
- Функция MongoCursor::sort() - Sorts the results by given fields
- Функция MongoCursor::tailable() - Sets whether this cursor will be left open after fetching the last results
- Функция MongoCursor::timeout() - Sets a client-side timeout for this query
- Функция MongoCursor::valid() - Checks if the cursor is reading a valid result.
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