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MariaDB Galera 集群，强制同步

tag-icon • tag-icon cluster mariadb galera
MariaDB Galera 集群，强制同步

我在多主 Galera 集群中拥有三台服务器。我最近导入了一些旧数据库，并注意到这三个数据库上都创建了表，但数据没有被复制。原来是我没注意，这些旧数据库都使用 MyISAM 表。所以我知道，将来我需要先将它们转换为 InnoDB，然后再将它们引入，才能使它们正常工作。

但是，我找不到同步现有数据的官方方法。运行ALTER TABLE将现有表转换为 InnoDB 不会同步现有数据。

我的想法是使用 转储表（现在已经转换）mysqldump，然后使用 将其恢复mysql -u user -p db < db.sql。我不明白为什么这样做行不通，但我想知道是否有更好的方法。

答案1

我找不到官方的方法来处理这个问题，所以我想单独转储表并重新导入它们。我不想手动操作，所以我编写了一个 PHP 脚本来帮我做这件事。我把它发布在这里，以防其他人觉得这有用。

/*
 * InnoDB Convert
 * Converts existing non-InnoDB tables to InnoDB, then re-imports the
 * data so that it's replicated across the cluster.
 */

// Configuration
    $_config['db'] = array(
        'type'     => 'mysql',
        'host'     => 'localhost',
        'username' => 'user',
        'password' => 'password'
    );

// Establish database connection
    try {
        $pdo = new PDO(
            $_config['db']['type'] . ':host=' . $_config['db']['host'],
            $_config['db']['username'],
            $_config['db']['password']
        );
    } catch ( PDOException $e ) {
        echo 'Connection failed: ' . $e->getMessage();
    }

// Get list of databases
    $db_query = <<<SQL
  SHOW DATABASES
SQL;
    $db_result = $pdo->prepare( $db_query );
    $db_result->execute();

    while ( $db_row = $db_result->fetch( PDO::FETCH_ASSOC )) {
    // Look through databases, but ignores the ones that come with a
    // MySQL install and shouldn't be part of the cluster
        if ( !in_array( $db_row['Database'], array( 'information_schema', 'mysql', 'performance_schema', 'testdb' ))) {
            $pdo->exec( "USE {$db_row['Database']}" );

            $table_query = <<<SQL
  SHOW TABLES
SQL;
            $table_result = $pdo->prepare( $table_query );
            $table_result->execute();

            while ( $table_row = $table_result->fetch( PDO::FETCH_ASSOC )) {
            // Loop through all tables
                $table = $table_row["Tables_in_{$db_row['Database']}"];

                $engine_query = <<<SQL
  SHOW TABLE STATUS WHERE Name = :table
SQL;
                $engine_result = $pdo->prepare( $engine_query );
                $engine_result->execute( array(
                    ':table' => $table
                ));

                $engine_row = $engine_result->fetch( PDO::FETCH_ASSOC );

                if ( $engine_row['Engine'] != 'InnoDB' ) {
                // Engine is not equal to InnoDB, let's convert it
                    echo "Converting '$table' on '{$db_row['Database']}' from '{$engine_row['Engine']}' to InnoDB:\n";

                    echo     "Modifying engine...";

                    $change_query = <<<SQL
  ALTER TABLE $table ENGINE=InnoDB
SQL;
                    $change_result = $pdo->prepare( $change_query );
                    $change_result->execute();

                    echo "done!\n";

                    echo "    Exporting table...";

                    exec( "mysqldump -h {$_config['db']['host']} -u {$_config['db']['username']} -p{$_config['db']['password']} {$db_row['Database']} $table > /tmp/dump-file.sql" );

                    echo "done!\n";

                    echo "    Re-importing table...";

                    exec( "mysql -h {$_config['db']['host']} -u {$_config['db']['username']} -p{$_config['db']['password']} {$db_row['Database']} < /tmp/dump-file.sql" );

                    echo "done!\n";

                    unlink( '/tmp/dump-file.sql' );

                    echo "done!\n";
                }
            }
        }
    }

我成功地用它在大约两分钟内转换了几十个数据库中的数百个表。

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