LoadBalancerTest.php

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<?php
 
use Wikimedia\Rdbms\DBError;
use Wikimedia\Rdbms\DatabaseDomain;
use Wikimedia\Rdbms\Database;
use Wikimedia\Rdbms\LoadBalancer;
use Wikimedia\Rdbms\LoadMonitorNull;
 
class LoadBalancerTest extends MediaWikiTestCase {
    private function makeServerConfig() {
        global $wgDBserver, $wgDBname, $wgDBuser, $wgDBpassword, $wgDBtype, $wgSQLiteDataDir;
 
        return [
            'host' => $wgDBserver,
            'dbname' => $wgDBname,
            'tablePrefix' => $this->dbPrefix(),
            'user' => $wgDBuser,
            'password' => $wgDBpassword,
            'type' => $wgDBtype,
            'dbDirectory' => $wgSQLiteDataDir,
            'load' => 0,
            'flags' => DBO_TRX // REPEATABLE-READ for consistency
        ];
    }
 
    public function testWithoutReplica() {
        global $wgDBname;
 
        $called = false;
        $lb = new LoadBalancer( [
            'servers' => [ $this->makeServerConfig() ],
            'queryLogger' => MediaWiki\Logger\LoggerFactory::getInstance( 'DBQuery' ),
            'localDomain' => new DatabaseDomain( $wgDBname, null, $this->dbPrefix() ),
            'chronologyCallback' => function () use ( &$called ) {
                $called = true;
            }
        ] );
 
        $ld = DatabaseDomain::newFromId( $lb->getLocalDomainID() );
        $this->assertEquals( $wgDBname, $ld->getDatabase(), 'local domain DB set' );
        $this->assertEquals( $this->dbPrefix(), $ld->getTablePrefix(), 'local domain prefix set' );
        $this->assertSame( 'my_test_wiki', $lb->resolveDomainID( 'my_test_wiki' ) );
        $this->assertSame( $ld->getId(), $lb->resolveDomainID( false ) );
        $this->assertSame( $ld->getId(), $lb->resolveDomainID( $ld ) );
 
        $this->assertFalse( $called );
        $dbw = $lb->getConnection( DB_MASTER );
        $this->assertTrue( $called );
        $this->assertTrue( $dbw->getLBInfo( 'master' ), 'master shows as master' );
        $this->assertTrue( $dbw->getFlag( $dbw::DBO_TRX ), "DBO_TRX set on master" );
        $this->assertWriteAllowed( $dbw );
 
        $dbr = $lb->getConnection( DB_REPLICA );
        $this->assertTrue( $dbr->getLBInfo( 'master' ), 'DB_REPLICA also gets the master' );
        $this->assertTrue( $dbr->getFlag( $dbw::DBO_TRX ), "DBO_TRX set on replica" );
 
        if ( !$lb->getServerAttributes( $lb->getWriterIndex() )[$dbw::ATTR_DB_LEVEL_LOCKING] ) {
            $dbwAuto = $lb->getConnection( DB_MASTER, [], false, $lb::CONN_TRX_AUTOCOMMIT );
            $this->assertFalse(
                $dbwAuto->getFlag( $dbw::DBO_TRX ), "No DBO_TRX with CONN_TRX_AUTOCOMMIT" );
            $this->assertTrue( $dbw->getFlag( $dbw::DBO_TRX ), "DBO_TRX still set on master" );
            $this->assertNotEquals(
                $dbw, $dbwAuto, "CONN_TRX_AUTOCOMMIT uses separate connection" );
 
            $dbrAuto = $lb->getConnection( DB_REPLICA, [], false, $lb::CONN_TRX_AUTOCOMMIT );
            $this->assertFalse(
                $dbrAuto->getFlag( $dbw::DBO_TRX ), "No DBO_TRX with CONN_TRX_AUTOCOMMIT" );
            $this->assertTrue( $dbr->getFlag( $dbw::DBO_TRX ), "DBO_TRX still set on replica" );
            $this->assertNotEquals(
                $dbr, $dbrAuto, "CONN_TRX_AUTOCOMMIT uses separate connection" );
 
            $dbwAuto2 = $lb->getConnection( DB_MASTER, [], false, $lb::CONN_TRX_AUTOCOMMIT );
            $this->assertEquals( $dbwAuto2, $dbwAuto, "CONN_TRX_AUTOCOMMIT reuses connections" );
        }
 
        $lb->closeAll();
    }
 
    public function testWithReplica() {
        global $wgDBserver, $wgDBname, $wgDBuser, $wgDBpassword, $wgDBtype, $wgSQLiteDataDir;
 
        $servers = [
            [ // master
                'host'        => $wgDBserver,
                'dbname'      => $wgDBname,
                'tablePrefix' => $this->dbPrefix(),
                'user'        => $wgDBuser,
                'password'    => $wgDBpassword,
                'type'        => $wgDBtype,
                'dbDirectory' => $wgSQLiteDataDir,
                'load'        => 0,
                'flags'       => DBO_TRX // REPEATABLE-READ for consistency
            ],
            [ // emulated replica
                'host'        => $wgDBserver,
                'dbname'      => $wgDBname,
                'tablePrefix' => $this->dbPrefix(),
                'user'        => $wgDBuser,
                'password'    => $wgDBpassword,
                'type'        => $wgDBtype,
                'dbDirectory' => $wgSQLiteDataDir,
                'load'        => 100,
                'flags'       => DBO_TRX // REPEATABLE-READ for consistency
            ]
        ];
 
        $lb = new LoadBalancer( [
            'servers' => $servers,
            'localDomain' => new DatabaseDomain( $wgDBname, null, $this->dbPrefix() ),
            'queryLogger' => MediaWiki\Logger\LoggerFactory::getInstance( 'DBQuery' ),
            'loadMonitorClass' => LoadMonitorNull::class
        ] );
 
        $dbw = $lb->getConnection( DB_MASTER );
        $this->assertTrue( $dbw->getLBInfo( 'master' ), 'master shows as master' );
        $this->assertEquals(
            ( $wgDBserver != '' ) ? $wgDBserver : 'localhost',
            $dbw->getLBInfo( 'clusterMasterHost' ),
            'cluster master set' );
        $this->assertTrue( $dbw->getFlag( $dbw::DBO_TRX ), "DBO_TRX set on master" );
        $this->assertWriteAllowed( $dbw );
 
        $dbr = $lb->getConnection( DB_REPLICA );
        $this->assertTrue( $dbr->getLBInfo( 'replica' ), 'replica shows as replica' );
        $this->assertEquals(
            ( $wgDBserver != '' ) ? $wgDBserver : 'localhost',
            $dbr->getLBInfo( 'clusterMasterHost' ),
            'cluster master set' );
        $this->assertTrue( $dbr->getFlag( $dbw::DBO_TRX ), "DBO_TRX set on replica" );
        $this->assertWriteForbidden( $dbr );
 
        if ( !$lb->getServerAttributes( $lb->getWriterIndex() )[$dbw::ATTR_DB_LEVEL_LOCKING] ) {
            $dbwAuto = $lb->getConnection( DB_MASTER, [], false, $lb::CONN_TRX_AUTOCOMMIT );
            $this->assertFalse(
                $dbwAuto->getFlag( $dbw::DBO_TRX ), "No DBO_TRX with CONN_TRX_AUTOCOMMIT" );
            $this->assertTrue( $dbw->getFlag( $dbw::DBO_TRX ), "DBO_TRX still set on master" );
            $this->assertNotEquals(
                $dbw, $dbwAuto, "CONN_TRX_AUTOCOMMIT uses separate connection" );
 
            $dbrAuto = $lb->getConnection( DB_REPLICA, [], false, $lb::CONN_TRX_AUTOCOMMIT );
            $this->assertFalse(
                $dbrAuto->getFlag( $dbw::DBO_TRX ), "No DBO_TRX with CONN_TRX_AUTOCOMMIT" );
            $this->assertTrue( $dbr->getFlag( $dbw::DBO_TRX ), "DBO_TRX still set on replica" );
            $this->assertNotEquals(
                $dbr, $dbrAuto, "CONN_TRX_AUTOCOMMIT uses separate connection" );
 
            $dbwAuto2 = $lb->getConnection( DB_MASTER, [], false, $lb::CONN_TRX_AUTOCOMMIT );
            $this->assertEquals( $dbwAuto2, $dbwAuto, "CONN_TRX_AUTOCOMMIT reuses connections" );
        }
 
        $lb->closeAll();
    }
 
    private function assertWriteForbidden( Database $db ) {
        try {
            $db->delete( 'some_table', [ 'id' => 57634126 ], __METHOD__ );
            $this->fail( 'Write operation should have failed!' );
        } catch ( DBError $ex ) {
            // check that the exception message contains "Write operation"
            $constraint = new PHPUnit_Framework_Constraint_StringContains( 'Write operation' );
 
            if ( !$constraint->evaluate( $ex->getMessage(), '', true ) ) {
                // re-throw original error, to preserve stack trace
                throw $ex;
            }
        }
    }
 
    private function assertWriteAllowed( Database $db ) {
        $table = $db->tableName( 'some_table' );
        // Trigger a transaction so that rollback() will remove all the tables.
        // Don't do this for MySQL/Oracle as they auto-commit transactions for DDL
        // statements such as CREATE TABLE.
        $useAtomicSection = in_array( $db->getType(), [ 'sqlite', 'postgres', 'mssql' ], true );
        try {
            $db->dropTable( 'some_table' ); // clear for sanity
            $this->assertNotEquals( $db::STATUS_TRX_ERROR, $db->trxStatus() );
 
            if ( $useAtomicSection ) {
                $db->startAtomic( __METHOD__ );
            }
            // Use only basic SQL and trivial types for these queries for compatibility
            $this->assertNotSame(
                false,
                $db->query( "CREATE TABLE $table (id INT, time INT)", __METHOD__ ),
                "table created"
            );
            $this->assertNotEquals( $db::STATUS_TRX_ERROR, $db->trxStatus() );
            $this->assertNotSame(
                false,
                $db->query( "DELETE FROM $table WHERE id=57634126", __METHOD__ ),
                "delete query"
            );
            $this->assertNotEquals( $db::STATUS_TRX_ERROR, $db->trxStatus() );
        } finally {
            if ( !$useAtomicSection ) {
                // Drop the table to clean up, ignoring any error.
                $db->dropTable( 'some_table' );
            }
            // Rollback the atomic section for sqlite's benefit.
            $db->rollback( __METHOD__, 'flush' );
            $this->assertNotEquals( $db::STATUS_TRX_ERROR, $db->trxStatus() );
        }
    }
 
    public function testServerAttributes() {
        $servers = [
            [ // master
                'dbname'      => 'my_unittest_wiki',
                'tablePrefix' => 'unittest_',
                'type'        => 'sqlite',
                'dbDirectory' => "some_directory",
                'load'        => 0
            ]
        ];
 
        $lb = new LoadBalancer( [
            'servers' => $servers,
            'localDomain' => new DatabaseDomain( 'my_unittest_wiki', null, 'unittest_' ),
            'loadMonitorClass' => LoadMonitorNull::class
        ] );
 
        $this->assertTrue( $lb->getServerAttributes( 0 )[Database::ATTR_DB_LEVEL_LOCKING] );
 
        $servers = [
            [ // master
                'host'        => 'db1001',
                'user'        => 'wikiuser',
                'password'    => 'none',
                'dbname'      => 'my_unittest_wiki',
                'tablePrefix' => 'unittest_',
                'type'        => 'mysql',
                'load'        => 100
            ],
            [ // emulated replica
                'host'        => 'db1002',
                'user'        => 'wikiuser',
                'password'    => 'none',
                'dbname'      => 'my_unittest_wiki',
                'tablePrefix' => 'unittest_',
                'type'        => 'mysql',
                'load'        => 100
            ]
        ];
 
        $lb = new LoadBalancer( [
            'servers' => $servers,
            'localDomain' => new DatabaseDomain( 'my_unittest_wiki', null, 'unittest_' ),
            'loadMonitorClass' => LoadMonitorNull::class
        ] );
 
        $this->assertFalse( $lb->getServerAttributes( 1 )[Database::ATTR_DB_LEVEL_LOCKING] );
    }
 
    function testOpenConnection() {
        global $wgDBname;
 
        $lb = new LoadBalancer( [
            'servers' => [ $this->makeServerConfig() ],
            'localDomain' => new DatabaseDomain( $wgDBname, null, $this->dbPrefix() )
        ] );
 
        $i = $lb->getWriterIndex();
        $this->assertEquals( null, $lb->getAnyOpenConnection( $i ) );
        $conn1 = $lb->getConnection( $i );
        $this->assertNotEquals( null, $conn1 );
        $this->assertEquals( $conn1, $lb->getAnyOpenConnection( $i ) );
        $conn2 = $lb->getConnection( $i, [], false, $lb::CONN_TRX_AUTOCOMMIT );
        $this->assertNotEquals( null, $conn2 );
        if ( $lb->getServerAttributes( $i )[Database::ATTR_DB_LEVEL_LOCKING] ) {
            $this->assertEquals( null,
                $lb->getAnyOpenConnection( $i, $lb::CONN_TRX_AUTOCOMMIT ) );
            $this->assertEquals( $conn1,
                $lb->getConnection(
                    $i, [], false, $lb::CONN_TRX_AUTOCOMMIT ), $lb::CONN_TRX_AUTOCOMMIT );
        } else {
            $this->assertEquals( $conn2,
                $lb->getAnyOpenConnection( $i, $lb::CONN_TRX_AUTOCOMMIT ) );
            $this->assertEquals( $conn2,
                $lb->getConnection( $i, [], false, $lb::CONN_TRX_AUTOCOMMIT ) );
 
            $conn2->startAtomic( __METHOD__ );
            try {
                $lb->getConnection( $i, [], false, $lb::CONN_TRX_AUTOCOMMIT );
                $conn2->endAtomic( __METHOD__ );
                $this->fail( "No exception thrown." );
            } catch ( DBUnexpectedError $e ) {
                $this->assertEquals(
                    'Wikimedia\Rdbms\LoadBalancer::openConnection: ' .
                    'CONN_TRX_AUTOCOMMIT handle has a transaction.',
                    $e->getMessage()
                );
            }
            $conn2->endAtomic( __METHOD__ );
        }
 
        $lb->closeAll();
    }
 
    public function testTransactionCallbackChains() {
        global $wgDBserver, $wgDBname, $wgDBuser, $wgDBpassword, $wgDBtype, $wgSQLiteDataDir;
 
        $servers = [
            [
                'host' => $wgDBserver,
                'dbname' => $wgDBname,
                'tablePrefix' => $this->dbPrefix(),
                'user' => $wgDBuser,
                'password' => $wgDBpassword,
                'type' => $wgDBtype,
                'dbDirectory' => $wgSQLiteDataDir,
                'load' => 0,
                'flags' => DBO_TRX // REPEATABLE-READ for consistency
            ],
        ];
 
        $lb = new LoadBalancer( [
            'servers' => $servers,
            'localDomain' => new DatabaseDomain( $wgDBname, null, $this->dbPrefix() )
        ] );
 
        $conn1 = $lb->openConnection( $lb->getWriterIndex(), false );
        $conn2 = $lb->openConnection( $lb->getWriterIndex(), '' );
 
        $count = 0;
        $lb->forEachOpenMasterConnection( function () use ( &$count ) {
            ++$count;
        } );
        $this->assertEquals( 2, $count, 'Connection handle count' );
 
        $tlCalls = 0;
        $lb->setTransactionListener( 'test-listener', function () use ( &$tlCalls ) {
            ++$tlCalls;
        } );
 
        $lb->beginMasterChanges( __METHOD__ );
        $bc = array_fill_keys( [ 'a', 'b', 'c', 'd' ], 0 );
        $conn1->onTransactionPreCommitOrIdle( function () use ( &$bc, $conn1, $conn2 ) {
            $bc['a'] = 1;
            $conn2->onTransactionPreCommitOrIdle( function () use ( &$bc, $conn1, $conn2 ) {
                $bc['b'] = 1;
                $conn1->onTransactionPreCommitOrIdle( function () use ( &$bc, $conn1, $conn2 ) {
                    $bc['c'] = 1;
                    $conn1->onTransactionPreCommitOrIdle( function () use ( &$bc, $conn1, $conn2 ) {
                        $bc['d'] = 1;
                    } );
                } );
            } );
        } );
        $lb->finalizeMasterChanges();
        $lb->approveMasterChanges( [] );
        $lb->commitMasterChanges( __METHOD__ );
        $lb->runMasterTransactionIdleCallbacks();
        $lb->runMasterTransactionListenerCallbacks();
 
        $this->assertEquals( array_fill_keys( [ 'a', 'b', 'c', 'd' ], 1 ), $bc );
        $this->assertEquals( 2, $tlCalls );
 
        $tlCalls = 0;
        $lb->beginMasterChanges( __METHOD__ );
        $ac = array_fill_keys( [ 'a', 'b', 'c', 'd' ], 0 );
        $conn1->onTransactionCommitOrIdle( function () use ( &$ac, $conn1, $conn2 ) {
            $ac['a'] = 1;
            $conn2->onTransactionCommitOrIdle( function () use ( &$ac, $conn1, $conn2 ) {
                $ac['b'] = 1;
                $conn1->onTransactionCommitOrIdle( function () use ( &$ac, $conn1, $conn2 ) {
                    $ac['c'] = 1;
                    $conn1->onTransactionCommitOrIdle( function () use ( &$ac, $conn1, $conn2 ) {
                        $ac['d'] = 1;
                    } );
                } );
            } );
        } );
        $lb->finalizeMasterChanges();
        $lb->approveMasterChanges( [] );
        $lb->commitMasterChanges( __METHOD__ );
        $lb->runMasterTransactionIdleCallbacks();
        $lb->runMasterTransactionListenerCallbacks();
 
        $this->assertEquals( array_fill_keys( [ 'a', 'b', 'c', 'd' ], 1 ), $ac );
        $this->assertEquals( 2, $tlCalls );
 
        $conn1->close();
        $conn2->close();
    }
}