DatabaseMigrations trait exhausts database connections

[mfn]

Using DatabaseMigrations with a lot of tests will exhaust all connections to the dabatase, i.e. they're not freed/returned to the system.

How to reproduce, as suggested from http://laravel.com/docs/5.1/testing#resetting-the-database-after-each-test :

1. composer.phar create-project laravel/laravel --prefer-dist
2. cd laravel
3. Change .env to point to a valid database connecion
4. Create a test script with many tests, using the trait; e.g. using this bash lines:

echo "<?php class ExhaustionTest extends TestCase {" > tests/ExhaustionTest.php
echo "use Illuminate\Foundation\Testing\DatabaseMigrations;" >> tests/ExhaustionTest.php
for i in $(seq 1 500); do echo "function test$i() {}" >>  tests/ExhaustionTest.php; done
echo "}" >> tests/ExhaustionTest.php

5. Run the tests with vendor/bin/phpunit

After a some tests they start to fail with the following error (or similar, depending on your DB):
PDOException: SQLSTATE[08004] [1040] Too many connections

Here's an example trace:

1) ExhaustionTest::test143
PDOException: SQLSTATE[08004] [1040] Too many connections

/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Connectors/Connector.php:55
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Connectors/MySqlConnector.php:22
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Connectors/ConnectionFactory.php:60
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Connectors/ConnectionFactory.php:49
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/DatabaseManager.php:175
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/DatabaseManager.php:67
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Migrations/DatabaseMigrationRepository.php:171
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Migrations/DatabaseMigrationRepository.php:139
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:393
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:100
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:58
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php:503
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Console/Command.php:150
/home/vagrant/src/test/laravel/vendor/symfony/console/Command/Command.php:259
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Console/Command.php:136
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Console/Application.php:62
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php:159
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Foundation/Testing/ApplicationTrait.php:299
/home/vagrant/src/test/laravel/vendor/laravel/framework/src/Illuminate/Foundation/Testing/DatabaseMigrations.php:12

To fix this for my suite, I created a trait similar to this:

trait DatabaseMigrationsCleanupTrait
{
    use Illuminate\Foundation\Testing\DatabaseMigrations;

    /**
     * @after
     */
    public function disconnectAllDatabases()
    {
        /** @var \Illuminate\Database\Connection $connection */
        foreach (\DB::getConnections() as $connection) {
            $connection->disconnect();
        }
    }
}

I would open a PR if someone points me in the right direction where the fix would be appropriate.

I tried this, which also worked:

diff --git a/vendor/laravel/framework/src/Illuminate/Foundation/Testing/DatabaseMigrations.php b/vendor/laravel/framework/src/Illuminate/Foundation/Testing/DatabaseMigrations.php
index d53b34e..b4a3205 100644
--- a/vendor/laravel/framework/src/Illuminate/Foundation/Testing/DatabaseMigrations.php
+++ b/vendor/laravel/framework/src/Illuminate/Foundation/Testing/DatabaseMigrations.php
@@ -13,6 +13,9 @@ trait DatabaseMigrations

         $this->beforeApplicationDestroyed(function () {
             $this->artisan('migrate:rollback');
+            foreach (\DB::getConnections() as $connection) {
+                $connection->disconnect();
+            }
         });
     }
 }

[GrahamCampbell]

This should happen anyway?

[GrahamCampbell]

When the applications are destroyed the connections should be garbage collected. Have you turned off the garbage collector?

[GrahamCampbell]

\DB::getConnections()

You definitely wouldn't want to do that. You'd want to call this->app->...

[mfn]

Have you turned off the garbage collector?

Not that I'm aware of. Tested with

$ php -v 
PHP 5.6.14-1+deb.sury.org~trusty+1 (cli)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2015 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2015, by Zend Technologies

$ php -i|grep enable_gc
zend.enable_gc => On => On

from https://launchpad.net/~ondrej/+archive/ubuntu/php5 for Ubuntu 14.04 LTS

You definitely wouldn't want to do that. You'd want to call this->app->...

Yeah, I thought so ... :-)

The underlying PDO does not support explicit disconnects and relies on being unrefed, maybe there's a dangling reference kept somewhere.

[pulkitjalan]

Having the same issue with the DatabaseTransactions trait.

$ php -v
PHP 5.5.9-1ubuntu4.11 (cli) (built: Jul  2 2015 15:23:08) 
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies
    with Zend OPcache v7.0.3, Copyright (c) 1999-2014, by Zend Technologies
    with Xdebug v2.2.3, Copyright (c) 2002-2013, by Derick Rethans

$ php -i | grep enable_gc
zend.enable_gc => On => On

The above fix solves the issue for me.

foreach ($this->app->make('db')->getConnections() as $connection) {
    $connection->disconnect();
}

[mfn]

I've switched my project from using the DatbaseMigrations to DatabaseTransactions and have seen the same problem.

I replaced it with my own trait, not only because of this bug, but also because the included DatabaseTransactions only covers the default connections and not others:

<?php

trait MultiDatabaseTransactionsTrait
{
    /**
     * @before
     */
    public function beginDatabaseTransaction()
    {
        /** @var \Illuminate\Database\DatabaseManager $db */
        $db = $this->app->make('db');
        $names = array_keys($this->app['config']['database.connections']);

        foreach ($names as $name) {
            $db->connection($name)->beginTransaction();
        }

        $this->beforeApplicationDestroyed(function () use ($db, $names) {
            foreach ($names as $name) {
                $connection = $db->connection($name);
                $connection->rollBack();
                $connection->disconnect();
            }
        });
    }
}

[mfn]

Why closed? This issue isn't solved?

[RomainLanz]

Look at the PR linked above #10731

[pulkitjalan]

That PR did not fix the issue and does not work. The pr was closed not merged.

[pulkitjalan]

This issue is still not solved.

[RomainLanz]

Did you read the PR?

cc @GrahamCampbell