const SLOW_WRITE_SEC = 0.500;
const SMALL_WRITE_ROWS = 100;
+ /** @var string Whether lock granularity is on the level of the entire database */
+ const ATTR_DB_LEVEL_LOCKING = 'db-level-locking';
+
/** @var string SQL query */
protected $lastQuery = '';
/** @var float|bool UNIX timestamp of last write query */
return $conn;
}
+ /**
+ * @param string $dbType A possible DB type (sqlite, mysql, postgres,...)
+ * @param string|null $driver Optional name of a specific DB client driver
+ * @return array Map of (Database::ATTRIBUTE_* constant => value) for all such constants
+ * @throws InvalidArgumentException
+ * @since 1.31
+ */
+ final public static function attributesFromType( $dbType, $driver = null ) {
+ static $defaults = [ self::ATTR_DB_LEVEL_LOCKING => false ];
+
+ $class = self::getClass( $dbType, $driver );
+
+ return call_user_func( [ $class, 'getAttributes' ] ) + $defaults;
+ }
+
/**
* @param string $dbType A possible DB type (sqlite, mysql, postgres,...)
* @param string|null $driver Optional name of a specific DB client driver
return $class;
}
+ /**
+ * @return array Map of (Database::ATTRIBUTE_* constant => value
+ * @since 1.31
+ */
+ protected static function getAttributes() {
+ return [];
+ }
+
/**
* Set the PSR-3 logger interface to use for query logging. (The logger
* interfaces for connection logging and error logging can be set with the
] );
}
+ protected static function getAttributes() {
+ return [ self::ATTR_DB_LEVEL_LOCKING => true ];
+ }
+
/**
* @param string $filename
* @param array $p Options map; supports:
/**
* Get a connection handle by server index
*
- * Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)
+ * The CONN_TRX_AUTO flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
+ * (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
+ * can be used to check such flags beforehand.
*
* If the caller uses $domain or sets CONN_TRX_AUTO in $flags, then it must also
* call ILoadBalancer::reuseConnection() on the handle when finished using it.
*
* The handle's methods simply wrap those of a Database handle
*
- * Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)
+ * The CONN_TRX_AUTO flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
+ * (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
+ * can be used to check such flags beforehand.
*
* @see ILoadBalancer::getConnection() for parameter information
*
*
* The handle's methods simply wrap those of a Database handle
*
- * Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)
+ * The CONN_TRX_AUTO flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
+ * (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
+ * can be used to check such flags beforehand.
*
* @see ILoadBalancer::getConnection() for parameter information
*
*
* The handle's methods simply wrap those of a Database handle
*
- * Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)
+ * The CONN_TRX_AUTO flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
+ * (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
+ * can be used to check such flags beforehand.
*
* @see ILoadBalancer::getConnection() for parameter information
*
* The index must be an actual index into the array. If a connection to the server is
* already open and not considered an "in use" foreign connection, this simply returns it.
*
- * Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)
+ * Avoid using CONN_TRX_AUTO for databases with ATTR_DB_LEVEL_LOCKING (e.g. sqlite) in
+ * order to avoid deadlocks. ILoadBalancer::getServerAttributes() can be used to check
+ * such flags beforehand.
*
* If the caller uses $domain or sets CONN_TRX_AUTO in $flags, then it must also
* call ILoadBalancer::reuseConnection() on the handle when finished using it.
*/
public function getServerType( $i );
+ /**
+ * @param int $i Server index
+ * @return array (Database::ATTRIBUTE_* constant => value) for all such constants
+ * @since 1.31
+ */
+ public function getServerAttributes( $i );
+
/**
* Get the current master position for chronology control purposes
* @return DBMasterPos|bool Returns false if not applicable
$domain = false; // local connection requested
}
+ if ( ( $flags & self::CONN_TRX_AUTO ) === self::CONN_TRX_AUTO ) {
+ // Assuming all servers are of the same type (or similar), which is overwhelmingly
+ // the case, use the master server information to get the attributes. The information
+ // for $i cannot be used since it might be DB_REPLICA, which might require connection
+ // attempts in order to be resolved into a real server index.
+ $attributes = $this->getServerAttributes( $this->getWriterIndex() );
+ if ( $attributes[Database::ATTR_DB_LEVEL_LOCKING] ) {
+ // Callers sometimes want to (a) escape REPEATABLE-READ stateness without locking
+ // rows (e.g. FOR UPDATE) or (b) make small commits during a larger transactions
+ // to reduce lock contention. None of these apply for sqlite and using separate
+ // connections just causes self-deadlocks.
+ $flags &= ~self::CONN_TRX_AUTO;
+ $this->connLogger->info( __METHOD__ . ': ignoring CONN_TRX_AUTO to avoid deadlocks.' );
+ }
+ }
+
$groups = ( $groups === false || $groups === [] )
? [ false ] // check one "group": the generic pool
: (array)$groups;
return $conn;
}
+ public function getServerAttributes( $i ) {
+ return Database::attributesFromType(
+ $this->getServerType( $i ),
+ isset( $this->servers[$i]['driver'] ) ? $this->servers[$i]['driver'] : null
+ );
+ }
+
/**
* Test if the specified index represents an open connection
*
$this->assertContains( 'SQLite ', $toString );
}
+
+ /**
+ * @covers \Wikimedia\Rdbms\DatabaseSqlite::getAttributes()
+ */
+ public function testsAttributes() {
+ $attributes = Database::attributesFromType( 'sqlite' );
+ $this->assertTrue( $attributes[Database::ATTR_DB_LEVEL_LOCKING] );
+ }
}
<?php
-use Wikimedia\Rdbms\DBError;
-use Wikimedia\Rdbms\LoadBalancer;
-use Wikimedia\Rdbms\DatabaseDomain;
-use Wikimedia\Rdbms\Database;
-
/**
* Holds tests for LoadBalancer MediaWiki class.
*
*
* @covers \Wikimedia\Rdbms\LoadBalancer
*/
+
+use Wikimedia\Rdbms\DBError;
+use Wikimedia\Rdbms\DatabaseDomain;
+use Wikimedia\Rdbms\Database;
+use Wikimedia\Rdbms\LoadBalancer;
+use Wikimedia\Rdbms\LoadMonitorNull;
+
class LoadBalancerTest extends MediaWikiTestCase {
public function testWithoutReplica() {
global $wgDBserver, $wgDBname, $wgDBuser, $wgDBpassword, $wgDBtype, $wgSQLiteDataDir;
}
}
+ 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] );
+ }
}
dépôts / lhc / web / wiklou.git / commitdiff