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MariaDB Galera 集群，強制同步

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MariaDB Galera 集群，強制同步

我在多主 Galera 叢集中有三台伺服器。我最近導入了一些舊資料庫，並注意到在所有三個資料庫中建立了表，但資料沒有被複製。原來是我沒注意，這些舊資料庫都用的是MyISAM表。所以我知道將來我需要將它們轉換為 InnoDB，然後再將它們引入以使它們工作。

但是，我沒有找到同步現有資料的官方方法。執行ALTER TABLE將現有表轉換為 InnoDB 不會同步現有資料。

我的想法是用 轉儲表（現在它已被轉換）mysqldump，然後用 重新將其帶回mysql -u user -p db < db.sql。我不明白為什麼這行不通，但我想知道是否有更好的方法。

答案1

我無法找到官方方法來處理這個問題，所以我想到了單獨轉儲表並重新匯入它們。由於不想手動完成此操作，我編寫了一個 PHP 腳本來幫助我完成此操作。我將其發佈在這裡以防其他人發現這有用。

/*
 * 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";
                }
            }
        }
    }

我成功地使用它在大約兩分鐘內轉換了幾十個資料庫中的數百個表。

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