Php/docs/mongocursor.explain
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MongoCursor::explain
(PECL mongo >=0.9.2)
MongoCursor::explain — Return an explanation of the query, often useful for optimization and debugging
说明
public MongoCursor::explain ( ) : array
参数
此函数没有参数。
返回值
Returns an explanation of the query.
范例
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());?>
以上例程的输出类似于:
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) { } } } }