Automatic mysql 4byte detection

config/config.sample.php

@@ -1234,16 +1234,23 @@
 'sqlite.journal_mode' => 'DELETE',
 
 /**
- * If this setting is set to true MySQL can handle 4 byte characters instead of
- * 3 byte characters
- *
+ * During setup, if requirements are met (see below), this setting is set to true
+ * and MySQL can handle 4 byte characters instead of 3 byte characters.
+ *
+ * If you want to convert an existing 3-byte setup into a 4-byte setup please 
+ * set the parameters in MySQL as mentioned below and run the migration command:
+ *  ./occ db:convert-mysql-charset
+ * The config setting will be set automatically after a successful run.
+ * 
+ * Consult the documentation for more details.
+ * 
  * MySQL requires a special setup for longer indexes (> 767 bytes) which are
  * needed:
  *
  * [mysqld]
- * innodb_large_prefix=true
- * innodb_file_format=barracuda
- * innodb_file_per_table=true
+ * innodb_large_prefix=ON
+ * innodb_file_format=Barracuda
+ * innodb_file_per_table=ON
  *
  * Tables will be created with
  *  * character set: utf8mb4
@@ -1256,8 +1263,6 @@
  * https://mariadb.com/kb/en/mariadb/xtradbinnodb-server-system-variables/#innodb_large_prefix
  * http://www.tocker.ca/2013/10/31/benchmarking-innodb-page-compression-performance.html
  * http://mechanics.flite.com/blog/2014/07/29/using-innodb-large-prefix-to-avoid-error-1071/
- *
- * WARNING: EXPERIMENTAL
  */
 'mysql.utf8mb4' => false,
 

core/Command/Db/ConvertMysqlToMB4.php

@@ -22,6 +22,7 @@
 namespace OC\Core\Command\Db;
 
 use Doctrine\DBAL\Platforms\MySqlPlatform;
+use OC\DB\MySqlTools;
 use OC\Migration\ConsoleOutput;
 use OC\Repair\Collation;
 use OCP\IConfig;
@@ -71,18 +72,17 @@ protected function execute(InputInterface $input, OutputInterface $output) {
 			return 1;
 		}
 
-		$oldValue = $this->config->getSystemValue('mysql.utf8mb4', false);
-		// enable charset
-		$this->config->setSystemValue('mysql.utf8mb4', true);
-
-		if (!$this->connection->supports4ByteText()) {
+		$tools = new MySqlTools();
+		if (!$tools->supports4ByteCharset($this->connection)) {
 			$url = $this->urlGenerator->linkToDocs('admin-mysql-utf8mb4');
 			$output->writeln("The database is not properly setup to use the charset utf8mb4.");
 			$output->writeln("For more information please read the documentation at $url");
-			$this->config->setSystemValue('mysql.utf8mb4', $oldValue);
 			return 1;
 		}
 
+		// enable charset
+		$this->config->setSystemValue('mysql.utf8mb4', true);
+
 		// run conversion
 		$coll = new Collation($this->config, $this->logger, $this->connection, false);
 		$coll->run(new ConsoleOutput($output));

lib/composer/composer/autoload_classmap.php

@@ -488,6 +488,7 @@
     'OC\\DB\\MigrationException' => $baseDir . '/lib/private/DB/MigrationException.php',
     'OC\\DB\\Migrator' => $baseDir . '/lib/private/DB/Migrator.php',
     'OC\\DB\\MySQLMigrator' => $baseDir . '/lib/private/DB/MySQLMigrator.php',
+    'OC\\DB\\MySqlTools' => $baseDir . '/lib/private/DB/MySqlTools.php',
     'OC\\DB\\NoCheckMigrator' => $baseDir . '/lib/private/DB/NoCheckMigrator.php',
     'OC\\DB\\OCSqlitePlatform' => $baseDir . '/lib/private/DB/OCSqlitePlatform.php',
     'OC\\DB\\OracleConnection' => $baseDir . '/lib/private/DB/OracleConnection.php',

lib/composer/composer/autoload_static.php

@@ -518,6 +518,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\DB\\MigrationException' => __DIR__ . '/../../..' . '/lib/private/DB/MigrationException.php',
         'OC\\DB\\Migrator' => __DIR__ . '/../../..' . '/lib/private/DB/Migrator.php',
         'OC\\DB\\MySQLMigrator' => __DIR__ . '/../../..' . '/lib/private/DB/MySQLMigrator.php',
+        'OC\\DB\\MySqlTools' => __DIR__ . '/../../..' . '/lib/private/DB/MySqlTools.php',
         'OC\\DB\\NoCheckMigrator' => __DIR__ . '/../../..' . '/lib/private/DB/NoCheckMigrator.php',
         'OC\\DB\\OCSqlitePlatform' => __DIR__ . '/../../..' . '/lib/private/DB/OCSqlitePlatform.php',
         'OC\\DB\\OracleConnection' => __DIR__ . '/../../..' . '/lib/private/DB/OracleConnection.php',

lib/private/DB/MySqlTools.php

@@ -0,0 +1,49 @@
+<?php
+/**
+ * @author Thomas Müller <[email protected]>
+ *
+ * @copyright Copyright (c) 2017, ownCloud GmbH
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\DB;
+
+use OCP\IDBConnection;
+
+/**
+* Various MySQL specific helper functions.
+*/
+class MySqlTools {
+
+	/**
+	 * @param Connection $connection
+	 * @return bool
+	 */
+	public function supports4ByteCharset(IDBConnection $connection) {
+		foreach (['innodb_file_format' => 'Barracuda', 'innodb_large_prefix' => 'ON', 'innodb_file_per_table' => 'ON'] as $var => $val) {
+			$result = $connection->executeQuery("SHOW VARIABLES LIKE '$var'");
+			$rows = $result->fetch();
+			$result->closeCursor();
+			if ($rows === false) {
+				return false;
+			}
+			if (strcasecmp($rows['Value'], $val) !== 0) {
+				return false;
+			}
+		}
+		return true;
+	}
+}

lib/private/Setup/MySQL.php

@@ -27,6 +27,7 @@
  */
 namespace OC\Setup;
 
+use OC\DB\MySqlTools;
 use OCP\IDBConnection;
 
 class MySQL extends AbstractDatabase {
@@ -36,6 +37,13 @@ public function setupDatabase($username) {
 		//check if the database user has admin right
 		$connection = $this->connect(['dbname' => null]);
 
+		// detect mb4
+		$tools = new MySqlTools();
+		if ($tools->supports4ByteCharset($connection)) {
+			$this->config->setValue('mysql.utf8mb4', true);
+			$connection = $this->connect();
+		}
+
 		$this->createSpecificUser($username, $connection);
 
 		//create the database