*
* This is meant for multi-wiki systems that may share files.
*
- * All lock requests for a resource, identified by a hash string, will map
- * to one bucket. Each bucket maps to one or several peer DBs, each on their
- * own server, all having the filelocks.sql tables (with row-level locking).
+ * All lock requests for a resource, identified by a hash string, will map to one bucket.
+ * Each bucket maps to one or several peer DBs, each on their own server.
* A majority of peer DBs must agree for a lock to be acquired.
*
* Caching is used to avoid hitting servers that are down.
* @param string $lockDb
* @return IDatabase
* @throws DBError
+ * @throws UnexpectedValueException
*/
protected function getConnection( $lockDb ) {
if ( !isset( $this->conns[$lockDb] ) ) {
- $db = null;
if ( $lockDb === 'localDBMaster' ) {
- $lb = wfGetLBFactory()->getMainLB( $this->domain );
+ $lb = $this->getLocalLB();
$db = $lb->getConnection( DB_MASTER, [], $this->domain );
+ # Do not mess with settings if the LoadBalancer is the main singleton
+ # to avoid clobbering the settings of handles from wfGetDB( DB_MASTER ).
+ $init = ( wfGetLB() !== $lb );
} elseif ( isset( $this->dbServers[$lockDb] ) ) {
$config = $this->dbServers[$lockDb];
$db = DatabaseBase::factory( $config['type'], $config );
+ $init = true;
+ } else {
+ throw new UnexpectedValueException( "No server called '$lockDb'." );
}
- if ( !$db ) {
- return null; // config error?
+
+ if ( $init ) {
+ $db->clearFlag( DBO_TRX );
+ # If the connection drops, try to avoid letting the DB rollback
+ # and release the locks before the file operations are finished.
+ # This won't handle the case of DB server restarts however.
+ $options = [];
+ if ( $this->lockExpiry > 0 ) {
+ $options['connTimeout'] = $this->lockExpiry;
+ }
+ $db->setSessionOptions( $options );
+ $this->initConnection( $lockDb, $db );
}
+
$this->conns[$lockDb] = $db;
- $this->conns[$lockDb]->clearFlag( DBO_TRX );
- # If the connection drops, try to avoid letting the DB rollback
- # and release the locks before the file operations are finished.
- # This won't handle the case of DB server restarts however.
- $options = [];
- if ( $this->lockExpiry > 0 ) {
- $options['connTimeout'] = $this->lockExpiry;
- }
- $this->conns[$lockDb]->setSessionOptions( $options );
- $this->initConnection( $lockDb, $this->conns[$lockDb] );
- }
- if ( !$this->conns[$lockDb]->trxLevel() ) {
- $this->conns[$lockDb]->begin( __METHOD__ ); // start transaction
}
return $this->conns[$lockDb];
}
+ /**
+ * @return LoadBalancer
+ */
+ protected function getLocalLB() {
+ return wfGetLBFactory()->getMainLB( $this->domain );
+ }
+
/**
* Do additional initialization for new lock DB connection
*
}
}
}
-
-/**
- * MySQL version of DBLockManager that supports shared locks.
- * All locks are non-blocking, which avoids deadlocks.
- *
- * @ingroup LockManager
- */
-class MySqlLockManager extends DBLockManager {
- /** @var array Mapping of lock types to the type actually used */
- protected $lockTypeMap = [
- self::LOCK_SH => self::LOCK_SH,
- self::LOCK_UW => self::LOCK_SH,
- self::LOCK_EX => self::LOCK_EX
- ];
-
- /**
- * @param string $lockDb
- * @param IDatabase $db
- */
- protected function initConnection( $lockDb, IDatabase $db ) {
- # Let this transaction see lock rows from other transactions
- $db->query( "SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;" );
- }
-
- /**
- * Get a connection to a lock DB and acquire locks on $paths.
- * This does not use GET_LOCK() per http://bugs.mysql.com/bug.php?id=1118.
- *
- * @see DBLockManager::getLocksOnServer()
- * @param string $lockSrv
- * @param array $paths
- * @param string $type
- * @return Status
- */
- protected function doGetLocksOnServer( $lockSrv, array $paths, $type ) {
- $status = Status::newGood();
-
- $db = $this->getConnection( $lockSrv ); // checked in isServerUp()
-
- $keys = []; // list of hash keys for the paths
- $data = []; // list of rows to insert
- $checkEXKeys = []; // list of hash keys that this has no EX lock on
- # Build up values for INSERT clause
- foreach ( $paths as $path ) {
- $key = $this->sha1Base36Absolute( $path );
- $keys[] = $key;
- $data[] = [ 'fls_key' => $key, 'fls_session' => $this->session ];
- if ( !isset( $this->locksHeld[$path][self::LOCK_EX] ) ) {
- $checkEXKeys[] = $key;
- }
- }
-
- # Block new writers (both EX and SH locks leave entries here)...
- $db->insert( 'filelocks_shared', $data, __METHOD__, [ 'IGNORE' ] );
- # Actually do the locking queries...
- if ( $type == self::LOCK_SH ) { // reader locks
- $blocked = false;
- # Bail if there are any existing writers...
- if ( count( $checkEXKeys ) ) {
- $blocked = $db->selectField( 'filelocks_exclusive', '1',
- [ 'fle_key' => $checkEXKeys ],
- __METHOD__
- );
- }
- # Other prospective writers that haven't yet updated filelocks_exclusive
- # will recheck filelocks_shared after doing so and bail due to this entry.
- } else { // writer locks
- $encSession = $db->addQuotes( $this->session );
- # Bail if there are any existing writers...
- # This may detect readers, but the safe check for them is below.
- # Note: if two writers come at the same time, both bail :)
- $blocked = $db->selectField( 'filelocks_shared', '1',
- [ 'fls_key' => $keys, "fls_session != $encSession" ],
- __METHOD__
- );
- if ( !$blocked ) {
- # Build up values for INSERT clause
- $data = [];
- foreach ( $keys as $key ) {
- $data[] = [ 'fle_key' => $key ];
- }
- # Block new readers/writers...
- $db->insert( 'filelocks_exclusive', $data, __METHOD__ );
- # Bail if there are any existing readers...
- $blocked = $db->selectField( 'filelocks_shared', '1',
- [ 'fls_key' => $keys, "fls_session != $encSession" ],
- __METHOD__
- );
- }
- }
-
- if ( $blocked ) {
- foreach ( $paths as $path ) {
- $status->fatal( 'lockmanager-fail-acquirelock', $path );
- }
- }
-
- return $status;
- }
-
- /**
- * @see QuorumLockManager::releaseAllLocks()
- * @return Status
- */
- protected function releaseAllLocks() {
- $status = Status::newGood();
-
- foreach ( $this->conns as $lockDb => $db ) {
- if ( $db->trxLevel() ) { // in transaction
- try {
- $db->rollback( __METHOD__ ); // finish transaction and kill any rows
- } catch ( DBError $e ) {
- $status->fatal( 'lockmanager-fail-db-release', $lockDb );
- }
- }
- }
-
- return $status;
- }
-}
-
-/**
- * PostgreSQL version of DBLockManager that supports shared locks.
- * All locks are non-blocking, which avoids deadlocks.
- *
- * @ingroup LockManager
- */
-class PostgreSqlLockManager extends DBLockManager {
- /** @var array Mapping of lock types to the type actually used */
- protected $lockTypeMap = [
- self::LOCK_SH => self::LOCK_SH,
- self::LOCK_UW => self::LOCK_SH,
- self::LOCK_EX => self::LOCK_EX
- ];
-
- protected function doGetLocksOnServer( $lockSrv, array $paths, $type ) {
- $status = Status::newGood();
- if ( !count( $paths ) ) {
- return $status; // nothing to lock
- }
-
- $db = $this->getConnection( $lockSrv ); // checked in isServerUp()
- $bigints = array_unique( array_map(
- function ( $key ) {
- return Wikimedia\base_convert( substr( $key, 0, 15 ), 16, 10 );
- },
- array_map( [ $this, 'sha1Base16Absolute' ], $paths )
- ) );
-
- // Try to acquire all the locks...
- $fields = [];
- foreach ( $bigints as $bigint ) {
- $fields[] = ( $type == self::LOCK_SH )
- ? "pg_try_advisory_lock_shared({$db->addQuotes( $bigint )}) AS K$bigint"
- : "pg_try_advisory_lock({$db->addQuotes( $bigint )}) AS K$bigint";
- }
- $res = $db->query( 'SELECT ' . implode( ', ', $fields ), __METHOD__ );
- $row = $res->fetchRow();
-
- if ( in_array( 'f', $row ) ) {
- // Release any acquired locks if some could not be acquired...
- $fields = [];
- foreach ( $row as $kbigint => $ok ) {
- if ( $ok === 't' ) { // locked
- $bigint = substr( $kbigint, 1 ); // strip off the "K"
- $fields[] = ( $type == self::LOCK_SH )
- ? "pg_advisory_unlock_shared({$db->addQuotes( $bigint )})"
- : "pg_advisory_unlock({$db->addQuotes( $bigint )})";
- }
- }
- if ( count( $fields ) ) {
- $db->query( 'SELECT ' . implode( ', ', $fields ), __METHOD__ );
- }
- foreach ( $paths as $path ) {
- $status->fatal( 'lockmanager-fail-acquirelock', $path );
- }
- }
-
- return $status;
- }
-
- /**
- * @see QuorumLockManager::releaseAllLocks()
- * @return Status
- */
- protected function releaseAllLocks() {
- $status = Status::newGood();
-
- foreach ( $this->conns as $lockDb => $db ) {
- try {
- $db->query( "SELECT pg_advisory_unlock_all()", __METHOD__ );
- } catch ( DBError $e ) {
- $status->fatal( 'lockmanager-fail-db-release', $lockDb );
- }
- }
-
- return $status;
- }
-}
dépôts / lhc / web / wiklou.git / blobdiff