DatabaseMysqlBase.php

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<?php
namespace Wikimedia\Rdbms;
 
use RuntimeException;
use Wikimedia\Rdbms\Platform\ISQLPlatform;
use Wikimedia\Rdbms\Platform\MySQLPlatform;
use Wikimedia\Rdbms\Replication\MysqlReplicationReporter;
 
abstract class DatabaseMysqlBase extends Database {
    protected $sslKeyPath;
    protected $sslCertPath;
    protected $sslCAFile;
    protected $sslCAPath;
    protected $sslCiphers;
    protected $utf8Mode;
    protected $defaultBigSelects;
 
    protected $platform;
 
    protected $replicationReporter;
 
    public function __construct( array $params ) {
        foreach ( [ 'KeyPath', 'CertPath', 'CAFile', 'CAPath', 'Ciphers' ] as $name ) {
            $var = "ssl{$name}";
            if ( isset( $params[$var] ) ) {
                $this->$var = $params[$var];
            }
        }
        $this->utf8Mode = !empty( $params['utf8Mode'] );
        parent::__construct( $params );
        $this->platform = new MySQLPlatform(
            $this,
            $this->logger,
            $this->currentDomain,
            $this->errorLogger
        );
        $this->replicationReporter = new MysqlReplicationReporter(
            $params['topologyRole'],
            $this->logger,
            $params['srvCache'],
            $params['lagDetectionMethod'] ?? 'Seconds_Behind_Master',
            $params['lagDetectionOptions'] ?? [],
            !empty( $params['useGTIDs' ] )
        );
    }
 
    public function getType() {
        return 'mysql';
    }
 
    protected function open( $server, $user, $password, $db, $schema, $tablePrefix ) {
        $this->close( __METHOD__ );
 
        if ( $schema !== null ) {
            throw $this->newExceptionAfterConnectError( "Got schema '$schema'; not supported." );
        }
 
        $this->installErrorHandler();
        try {
            $this->conn = $this->mysqlConnect( $server, $user, $password, $db );
        } catch ( RuntimeException $e ) {
            $this->restoreErrorHandler();
            throw $this->newExceptionAfterConnectError( $e->getMessage() );
        }
        $error = $this->restoreErrorHandler();
 
        if ( !$this->conn ) {
            throw $this->newExceptionAfterConnectError( $error ?: $this->lastError() );
        }
 
        try {
            $this->currentDomain = new DatabaseDomain(
                $db && strlen( $db ) ? $db : null,
                null,
                $tablePrefix
            );
            $this->platform->setPrefix( $tablePrefix );
            // Abstract over any excessive MySQL defaults
            $set = [ 'group_concat_max_len = 262144' ];
            // Set any custom settings defined by site config
            // https://dev.mysql.com/doc/refman/5.7/en/innodb-parameters.html
            foreach ( $this->connectionVariables as $var => $val ) {
                // Escape strings but not numbers to avoid MySQL complaining
                if ( !is_int( $val ) && !is_float( $val ) ) {
                    $val = $this->addQuotes( $val );
                }
                $set[] = $this->platform->addIdentifierQuotes( $var ) . ' = ' . $val;
            }
 
            // @phan-suppress-next-next-line PhanRedundantCondition
            // Safety check to avoid empty SET query
            if ( $set ) {
                $sql = 'SET ' . implode( ', ', $set );
                $flags = self::QUERY_NO_RETRY | self::QUERY_CHANGE_TRX;
                // Avoid using query() so that replaceLostConnection() does not throw
                // errors if the transaction status is STATUS_TRX_ERROR
                $qs = $this->executeQuery( $sql, __METHOD__, $flags, $sql );
                if ( $qs->res === false ) {
                    $this->reportQueryError( $qs->message, $qs->code, $sql, __METHOD__ );
                }
            }
        } catch ( RuntimeException $e ) {
            throw $this->newExceptionAfterConnectError( $e->getMessage() );
        }
    }
 
    protected function doSelectDomain( DatabaseDomain $domain ) {
        if ( $domain->getSchema() !== null ) {
            throw new DBExpectedError(
                $this,
                __CLASS__ . ": domain '{$domain->getId()}' has a schema component"
            );
        }
 
        $database = $domain->getDatabase();
        // A null database means "don't care" so leave it as is and update the table prefix
        if ( $database === null ) {
            $this->currentDomain = new DatabaseDomain(
                $this->currentDomain->getDatabase(),
                null,
                $domain->getTablePrefix()
            );
            $this->platform->setPrefix( $domain->getTablePrefix() );
 
            return true;
        }
 
        if ( $database !== $this->getDBname() ) {
            $sql = 'USE ' . $this->addIdentifierQuotes( $database );
            $qs = $this->executeQuery( $sql, __METHOD__, self::QUERY_IGNORE_DBO_TRX, $sql );
            if ( $qs->res === false ) {
                $this->reportQueryError( $qs->message, $qs->code, $sql, __METHOD__ );
                return false; // unreachable
            }
        }
 
        // Update that domain fields on success (no exception thrown)
        $this->currentDomain = $domain;
        $this->platform->setPrefix( $domain->getTablePrefix() );
 
        return true;
    }
 
    abstract protected function mysqlConnect( $server, $user, $password, $db );
 
    public function lastError() {
        if ( $this->conn ) {
            // Even if it's non-zero, it can still be invalid
            $error = $this->mysqlError( $this->conn );
            if ( !$error ) {
                $error = $this->mysqlError();
            }
        } else {
            $error = $this->mysqlError() ?: $this->lastConnectError;
        }
 
        return $error;
    }
 
    abstract protected function mysqlError( $conn = null );
 
    protected function isInsertSelectSafe( array $insertOptions, array $selectOptions ) {
        $row = $this->replicationReporter->getReplicationSafetyInfo( $this );
        // For row-based-replication, the resulting changes will be relayed, not the query
        if ( $row->binlog_format === 'ROW' ) {
            return true;
        }
        // LIMIT requires ORDER BY on a unique key or it is non-deterministic
        if ( isset( $selectOptions['LIMIT'] ) ) {
            return false;
        }
        // In MySQL, an INSERT SELECT is only replication safe with row-based
        // replication or if innodb_autoinc_lock_mode is 0. When those
        // conditions aren't met, use non-native mode.
        // While we could try to determine if the insert is safe anyway by
        // checking if the target table has an auto-increment column that
        // isn't set in $varMap, that seems unlikely to be worth the extra
        // complexity.
        return (
            in_array( 'NO_AUTO_COLUMNS', $insertOptions ) ||
            (int)$row->innodb_autoinc_lock_mode === 0
        );
    }
 
    public function estimateRowCount(
        $tables,
        $var = '*',
        $conds = '',
        $fname = __METHOD__,
        $options = [],
        $join_conds = []
    ) {
        $conds = $this->platform->normalizeConditions( $conds, $fname );
        $column = $this->platform->extractSingleFieldFromList( $var );
        if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
            $conds[] = "$column IS NOT NULL";
        }
 
        $options['EXPLAIN'] = true;
        $res = $this->select( $tables, $var, $conds, $fname, $options, $join_conds );
        if ( $res === false ) {
            return false;
        }
        if ( !$res->numRows() ) {
            return 0;
        }
 
        $rows = 1;
        foreach ( $res as $plan ) {
            $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
        }
 
        return (int)$rows;
    }
 
    public function tableExists( $table, $fname = __METHOD__ ) {
        // Split database and table into proper variables as Database::tableName() returns
        // shared tables prefixed with their database, which do not work in SHOW TABLES statements
        [ $database, , $prefix, $table ] = $this->platform->qualifiedTableComponents( $table );
        $tableName = "{$prefix}{$table}";
 
        if ( isset( $this->sessionTempTables[$tableName] ) ) {
            return true; // already known to exist and won't show in SHOW TABLES anyway
        }
 
        // We can't use buildLike() here, because it specifies an escape character
        // other than the backslash, which is the only one supported by SHOW TABLES
        // TODO: Avoid using platform's internal methods
        $encLike = $this->platform->escapeLikeInternal( $tableName, '\\' );
 
        // If the database has been specified (such as for shared tables), use "FROM"
        if ( $database !== '' ) {
            $encDatabase = $this->platform->addIdentifierQuotes( $database );
            $sql = "SHOW TABLES FROM $encDatabase LIKE '$encLike'";
        } else {
            $sql = "SHOW TABLES LIKE '$encLike'";
        }
 
        $res = $this->query(
            $sql,
            $fname,
            self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE
        );
 
        return $res->numRows() > 0;
    }
 
    public function fieldInfo( $table, $field ) {
        $res = $this->query(
            "SELECT * FROM " . $this->tableName( $table ) . " LIMIT 1",
            __METHOD__,
            self::QUERY_SILENCE_ERRORS | self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE
        );
        if ( !$res ) {
            return false;
        }
        '@phan-var MysqliResultWrapper $res';
        return $res->getInternalFieldInfo( $field );
    }
 
    public function indexInfo( $table, $index, $fname = __METHOD__ ) {
        # https://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
        $index = $this->indexName( $index );
 
        $res = $this->query(
            'SHOW INDEX FROM ' . $this->tableName( $table ),
            $fname,
            self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE
        );
 
        if ( !$res ) {
            return null;
        }
 
        $result = [];
 
        foreach ( $res as $row ) {
            if ( $row->Key_name == $index ) {
                $result[] = $row;
            }
        }
 
        return $result ?: false;
    }
 
    public function strencode( $s ) {
        return $this->mysqlRealEscapeString( $s );
    }
 
    abstract protected function mysqlRealEscapeString( $s );
 
    public function serverIsReadOnly() {
        // Avoid SHOW to avoid internal temporary tables
        $flags = self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE;
        $res = $this->query( "SELECT @@GLOBAL.read_only AS Value", __METHOD__, $flags );
        $row = $res->fetchObject();
 
        return $row ? (bool)$row->Value : false;
    }
 
    public function getSoftwareLink() {
        [ $variant ] = $this->getMySqlServerVariant();
        if ( $variant === 'MariaDB' ) {
            return '[{{int:version-db-mariadb-url}} MariaDB]';
        }
 
        return '[{{int:version-db-mysql-url}} MySQL]';
    }
 
    protected function getMySqlServerVariant() {
        $version = $this->getServerVersion();
 
        // MariaDB includes its name in its version string; this is how MariaDB's version of
        // the mysql command-line client identifies MariaDB servers.
        // https://dev.mysql.com/doc/refman/8.0/en/information-functions.html#function_version
        // https://mariadb.com/kb/en/version/
        $parts = explode( '-', $version, 2 );
        $number = $parts[0];
        $suffix = $parts[1] ?? '';
        if ( strpos( $suffix, 'MariaDB' ) !== false || strpos( $suffix, '-maria-' ) !== false ) {
            $vendor = 'MariaDB';
        } else {
            $vendor = 'MySQL';
        }
 
        return [ $vendor, $number ];
    }
 
    public function getServerVersion() {
        $cache = $this->srvCache;
        $fname = __METHOD__;
 
        return $cache->getWithSetCallback(
            $cache->makeGlobalKey( 'mysql-server-version', $this->getServerName() ),
            $cache::TTL_HOUR,
            function () use ( $fname ) {
                // Not using mysql_get_server_info() or similar for consistency: in the handshake,
                // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
                // it off (see RPL_VERSION_HACK in include/mysql_com.h).
                return $this->selectField( '', 'VERSION()', '', $fname );
            }
        );
    }
 
    public function setSessionOptions( array $options ) {
        $sqlAssignments = [];
 
        if ( isset( $options['connTimeout'] ) ) {
            $encTimeout = (int)$options['connTimeout'];
            $sqlAssignments[] = "net_read_timeout=$encTimeout";
            $sqlAssignments[] = "net_write_timeout=$encTimeout";
        }
 
        if ( $sqlAssignments ) {
            $this->query(
                'SET ' . implode( ', ', $sqlAssignments ),
                __METHOD__,
                self::QUERY_CHANGE_TRX | self::QUERY_CHANGE_NONE
            );
        }
    }
 
    public function streamStatementEnd( &$sql, &$newLine ) {
        if ( preg_match( '/^DELIMITER\s+(\S+)/i', $newLine, $m ) ) {
            $this->delimiter = $m[1];
            $newLine = '';
        }
 
        return parent::streamStatementEnd( $sql, $newLine );
    }
 
    public function doLockIsFree( string $lockName, string $method ) {
        $res = $this->query(
            $this->platform->lockIsFreeSQLText( $lockName ),
            $method,
            self::QUERY_CHANGE_LOCKS
        );
        $row = $res->fetchObject();
 
        return ( $row->unlocked == 1 );
    }
 
    public function doLock( string $lockName, string $method, int $timeout ) {
        $res = $this->query(
            $this->platform->lockSQLText( $lockName, $timeout ),
            $method,
            self::QUERY_CHANGE_LOCKS
        );
        $row = $res->fetchObject();
 
        return ( $row->acquired !== null ) ? (float)$row->acquired : null;
    }
 
    public function doUnlock( string $lockName, string $method ) {
        $res = $this->query(
            $this->platform->unlockSQLText( $lockName ),
            $method,
            self::QUERY_CHANGE_LOCKS
        );
        $row = $res->fetchObject();
 
        return ( $row->released == 1 );
    }
 
    public function namedLocksEnqueue() {
        return true;
    }
 
    protected function doFlushSession( $fname ) {
        $flags = self::QUERY_CHANGE_LOCKS | self::QUERY_NO_RETRY;
        // Note that RELEASE_ALL_LOCKS() is not supported well enough to use here.
        // https://mariadb.com/kb/en/release_all_locks/
        $releaseLockFields = [];
        foreach ( $this->sessionNamedLocks as $name => $info ) {
            $encName = $this->addQuotes( $this->platform->makeLockName( $name ) );
            $releaseLockFields[] = "RELEASE_LOCK($encName)";
        }
        if ( $releaseLockFields ) {
            $sql = 'SELECT ' . implode( ',', $releaseLockFields );
            $qs = $this->executeQuery( $sql, __METHOD__, $flags, $sql );
            if ( $qs->res === false ) {
                $this->reportQueryError( $qs->message, $qs->code, $sql, $fname, true );
            }
        }
    }
 
    protected function doUpsert(
        string $table,
        array $rows,
        array $identityKey,
        array $set,
        string $fname
    ) {
        $encTable = $this->tableName( $table );
        [ $sqlColumns, $sqlTuples ] = $this->platform->makeInsertLists( $rows );
        $sqlColumnAssignments = $this->makeList( $set, self::LIST_SET );
        // No need to expose __NEW.* since buildExcludedValue() uses VALUES(column)
 
        // https://mariadb.com/kb/en/insert-on-duplicate-key-update/
        // https://dev.mysql.com/doc/refman/8.0/en/insert-on-duplicate.html
        $sql =
            "INSERT INTO $encTable " .
            "($sqlColumns) VALUES $sqlTuples " .
            "ON DUPLICATE KEY UPDATE $sqlColumnAssignments";
 
        $this->query( $sql, $fname, self::QUERY_CHANGE_ROWS );
    }
 
    protected function doReplace( $table, array $identityKey, array $rows, $fname ) {
        $encTable = $this->tableName( $table );
        [ $sqlColumns, $sqlTuples ] = $this->platform->makeInsertLists( $rows );
 
        $sql = "REPLACE INTO $encTable ($sqlColumns) VALUES $sqlTuples";
 
        $this->query( $sql, $fname, self::QUERY_CHANGE_ROWS );
    }
 
    public function wasDeadlock() {
        return $this->lastErrno() == 1213;
    }
 
    public function wasLockTimeout() {
        return $this->lastErrno() == 1205;
    }
 
    public function wasReadOnlyError() {
        return $this->lastErrno() == 1223 ||
            ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
    }
 
    protected function isConnectionError( $errno ) {
        // https://mariadb.com/kb/en/mariadb-error-codes/
        // https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html
        // https://dev.mysql.com/doc/mysql-errors/8.0/en/client-error-reference.html
        return in_array( $errno, [ 2013, 2006, 2003, 1927, 1053 ], true );
    }
 
    protected function isQueryTimeoutError( $errno ) {
        // https://mariadb.com/kb/en/mariadb-error-codes/
        // https://dev.mysql.com/doc/refman/8.0/en/client-error-reference.html
        // https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html
        return in_array( $errno, [ 3024, 2062, 1969, 1028 ], true );
    }
 
    protected function isKnownStatementRollbackError( $errno ) {
        // https://mariadb.com/kb/en/mariadb-error-codes/
        // https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html
        return in_array(
            $errno,
            [ 3024, 1969, 1022, 1062, 1216, 1217, 1137, 1146, 1051, 1054 ],
            true
        );
    }
 
    public function duplicateTableStructure(
        $oldName, $newName, $temporary = false, $fname = __METHOD__
    ) {
        $tmp = $temporary ? 'TEMPORARY ' : '';
        $newName = $this->addIdentifierQuotes( $newName );
        $oldName = $this->addIdentifierQuotes( $oldName );
 
        return $this->query(
            "CREATE $tmp TABLE $newName (LIKE $oldName)",
            $fname,
            self::QUERY_PSEUDO_PERMANENT | self::QUERY_CHANGE_SCHEMA
        );
    }
 
    public function listTables( $prefix = null, $fname = __METHOD__ ) {
        $result = $this->query(
            "SHOW TABLES",
            $fname,
            self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE
        );
 
        $endArray = [];
 
        foreach ( $result as $table ) {
            $vars = get_object_vars( $table );
            $table = array_pop( $vars );
 
            if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
                $endArray[] = $table;
            }
        }
 
        return $endArray;
    }
 
    public function listViews( $prefix = null, $fname = __METHOD__ ) {
        // The name of the column containing the name of the VIEW
        $propertyName = 'Tables_in_' . $this->getDBname();
 
        // Query for the VIEWS
        $res = $this->query(
            'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"',
            $fname,
            self::QUERY_IGNORE_DBO_TRX | self::QUERY_CHANGE_NONE
        );
 
        $allViews = [];
        foreach ( $res as $row ) {
            array_push( $allViews, $row->$propertyName );
        }
 
        if ( $prefix === null || $prefix === '' ) {
            return $allViews;
        }
 
        $filteredViews = [];
        foreach ( $allViews as $viewName ) {
            // Does the name of this VIEW start with the table-prefix?
            if ( strpos( $viewName, $prefix ) === 0 ) {
                array_push( $filteredViews, $viewName );
            }
        }
 
        return $filteredViews;
    }
 
    public function isView( $name, $prefix = null ) {
        return in_array( $name, $this->listViews( $prefix, __METHOD__ ) );
    }
 
    public function selectSQLText(
        $table,
        $vars,
        $conds = '',
        $fname = __METHOD__,
        $options = [],
        $join_conds = []
    ) {
        $sql = parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
        // https://dev.mysql.com/doc/refman/5.7/en/optimizer-hints.html
        // https://mariadb.com/kb/en/library/aborting-statements/
        $timeoutMsec = intval( $options['MAX_EXECUTION_TIME'] ?? 0 );
        if ( $timeoutMsec > 0 ) {
            [ $vendor, $number ] = $this->getMySqlServerVariant();
            if ( $vendor === 'MariaDB' && version_compare( $number, '10.1.2', '>=' ) ) {
                $timeoutSec = $timeoutMsec / 1000;
                $sql = "SET STATEMENT max_statement_time=$timeoutSec FOR $sql";
            } elseif ( $vendor === 'MySQL' && version_compare( $number, '5.7.0', '>=' ) ) {
                $sql = preg_replace(
                    '/^SELECT(?=\s)/',
                    "SELECT /*+ MAX_EXECUTION_TIME($timeoutMsec)*/",
                    $sql
                );
            }
        }
 
        return $sql;
    }
}
 
class_alias( DatabaseMysqlBase::class, 'DatabaseMysqlBase' );