Memory leak while committing transactions in a loop #1163
Description
The query request in transaction enhances memory.
CentOS 8
php -v
PHP 7.4.9 (cli) (built: Aug 4 2020 08:28:13) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
with Zend OPcache v7.4.9, Copyright (c), by Zend Technologies
php --ri mongodb
MongoDB support => enabled
MongoDB extension version => 1.7.4
MongoDB extension stability => stable
libbson bundled version => 1.16.2
libmongoc bundled version => 1.16.2
libmongoc SSL => enabled
libmongoc SSL library => OpenSSL
libmongoc crypto => enabled
libmongoc crypto library => libcrypto
libmongoc crypto system profile => disabled
libmongoc SASL => disabled
libmongoc ICU => disabled
libmongoc compression => enabled
libmongoc compression snappy => disabled
libmongoc compression zlib => enabled
libmongocrypt bundled version => 1.0.3
libmongocrypt crypto => enabled
libmongocrypt crypto library => libcrypto
Directive => Local Value => Master Value
mongodb.debug => no value => no value
Test case
mongo.php
<?php
echo getmypid()."\n";
echo "sleep(7s)\n";
sleep(7);
echo 'Start';
$mng = new \MongoDB\Driver\Manager('mongodb://user:pass@127.0.0.1:27017/myDb');
$mng->selectServer($mng->getReadPreference());
$session = $mng->startSession();
while(true){
$session->startTransaction();
$id = new \MongoDB\BSON\ObjectId('5f721da0e16441233b631842');
$query = new \MongoDB\Driver\Query(['_id' => $id]);
$cursor = $mng->executeQuery('myDb.myCollection',$query,['session' => $session]);
$session->commitTransaction();
unset($id,$query,$cursor);
}mongo-monitor.php
<?php
while(true){
$result = exec("ps -q {$argv[1]} -o rss=",$_,$returnCode);
if($returnCode !== 0)
break;
echo $result."\n";
}run
root# php mongo.php
105825
sleep(7s)
root# php mongo-monitor.php 105825
why does memory increase?
how i can unset cursor and Free up memory?
thanks.