use HashBagOStuff;
use LogicException;
use InvalidArgumentException;
+use UnexpectedValueException;
use Exception;
use RuntimeException;
$this->flags |= self::DBO_TRX;
}
}
+ // Disregard deprecated DBO_IGNORE flag (T189999)
+ $this->flags &= ~self::DBO_IGNORE;
$this->sessionVars = $params['variables'];
return $res;
}
- /**
- * Turns on (false) or off (true) the automatic generation and sending
- * of a "we're sorry, but there has been a database error" page on
- * database errors. Default is on (false). When turned off, the
- * code should use lastErrno() and lastError() to handle the
- * situation as appropriate.
- *
- * Do not use this function outside of the Database classes.
- *
- * @param null|bool $ignoreErrors
- * @return bool The previous value of the flag.
- */
- protected function ignoreErrors( $ignoreErrors = null ) {
- $res = $this->getFlag( self::DBO_IGNORE );
- if ( $ignoreErrors !== null ) {
- // setFlag()/clearFlag() do not allow DBO_IGNORE changes for sanity
- if ( $ignoreErrors ) {
- $this->flags |= self::DBO_IGNORE;
- } else {
- $this->flags &= ~self::DBO_IGNORE;
- }
- }
-
- return $res;
- }
-
public function trxLevel() {
return $this->trxLevel;
}
);
}
+ /**
+ * @return string|null
+ */
+ final protected function getTransactionRoundId() {
+ // If transaction round participation is enabled, see if one is active
+ if ( $this->getFlag( self::DBO_TRX ) ) {
+ $id = $this->getLBInfo( 'trxRoundId' );
+
+ return is_string( $id ) ? $id : null;
+ }
+
+ return null;
+ }
+
public function pendingWriteQueryDuration( $type = self::ESTIMATE_TOTAL ) {
if ( !$this->trxLevel ) {
return false;
public function setFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
if ( ( $flag & self::DBO_IGNORE ) ) {
- throw new \UnexpectedValueException( "Modifying DBO_IGNORE is not allowed." );
+ throw new UnexpectedValueException( "Modifying DBO_IGNORE is not allowed." );
}
if ( $remember === self::REMEMBER_PRIOR ) {
public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
if ( ( $flag & self::DBO_IGNORE ) ) {
- throw new \UnexpectedValueException( "Modifying DBO_IGNORE is not allowed." );
+ throw new UnexpectedValueException( "Modifying DBO_IGNORE is not allowed." );
}
if ( $remember === self::REMEMBER_PRIOR ) {
*/
abstract protected function closeConnection();
+ /**
+ * @param string $error Fallback error message, used if none is given by DB
+ * @throws DBConnectionError
+ */
public function reportConnectionError( $error = 'Unknown error' ) {
$myError = $this->lastError();
if ( $myError ) {
# Avoid fatals if close() was called
$this->assertOpen();
- # Send the query to the server
+ # Send the query to the server and fetch any corresponding errors
$ret = $this->doProfiledQuery( $sql, $commentedSql, $isNonTempWrite, $fname );
+ $lastError = $this->lastError();
+ $lastErrno = $this->lastErrno();
# Try reconnecting if the connection was lost
- if ( false === $ret && $this->wasConnectionLoss() ) {
+ if ( $ret === false && $this->wasConnectionLoss() ) {
+ # Check if any meaningful session state was lost
$recoverable = $this->canRecoverFromDisconnect( $sql, $priorWritesPending );
- # Stash the last error values before anything might clear them
- $lastError = $this->lastError();
- $lastErrno = $this->lastErrno();
- # Update state tracking to reflect transaction loss due to disconnection
- $this->handleSessionLoss();
- if ( $this->reconnect() ) {
- $msg = __METHOD__ . ': lost connection to {dbserver}; reconnected';
- $params = [ 'dbserver' => $this->getServer() ];
- $this->connLogger->warning( $msg, $params );
- $this->queryLogger->warning( $msg, $params +
- [ 'trace' => ( new RuntimeException() )->getTraceAsString() ] );
-
- if ( $recoverable ) {
- # Should be safe to silently retry the query
- $ret = $this->doProfiledQuery( $sql, $commentedSql, $isNonTempWrite, $fname );
- } else {
- # Callers may catch the exception and continue to use the DB
- $this->reportQueryError( $lastError, $lastErrno, $sql, $fname );
+ # Update session state tracking and try to restore the connection
+ $reconnected = $this->replaceLostConnection( __METHOD__ );
+ # Silently resend the query to the server if it is safe and possible
+ if ( $reconnected && $recoverable ) {
+ $ret = $this->doProfiledQuery( $sql, $commentedSql, $isNonTempWrite, $fname );
+ $lastError = $this->lastError();
+ $lastErrno = $this->lastErrno();
+
+ if ( $ret === false && $this->wasConnectionLoss() ) {
+ # Query probably causes disconnects; reconnect and do not re-run it
+ $this->replaceLostConnection( __METHOD__ );
}
- } else {
- $msg = __METHOD__ . ': lost connection to {dbserver} permanently';
- $this->connLogger->error( $msg, [ 'dbserver' => $this->getServer() ] );
}
}
- if ( false === $ret ) {
+ if ( $ret === false ) {
# Deadlocks cause the entire transaction to abort, not just the statement.
# https://dev.mysql.com/doc/refman/5.7/en/innodb-error-handling.html
# https://www.postgresql.org/docs/9.1/static/explicit-locking.html
if ( $this->explicitTrxActive() || $priorWritesPending ) {
$tempIgnore = false; // not recoverable
}
+ # Usually the transaction is rolled back to BEGIN, leaving an empty transaction.
+ # Destroy any such transaction so the rollback callbacks run in AUTO-COMMIT mode
+ # as normal. Also, if DBO_TRX is set and an explicit transaction rolled back here,
+ # further queries should be back in AUTO-COMMIT mode, not stuck in a transaction.
+ $this->doRollback( __METHOD__ );
# Update state tracking to reflect transaction loss
- $this->handleSessionLoss();
+ $this->handleTransactionLoss();
}
- $this->reportQueryError(
- $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
+ $this->reportQueryError( $lastError, $lastErrno, $sql, $fname, $tempIgnore );
}
- $res = $this->resultObject( $ret );
-
- return $res;
+ return $this->resultObject( $ret );
}
/**
# didn't matter anyway (aside from DBO_TRX snapshot loss).
if ( $this->namedLocksHeld ) {
return false; // possible critical section violation
+ } elseif ( $this->sessionTempTables ) {
+ return false; // tables might be queried latter
} elseif ( $sql === 'COMMIT' ) {
return !$priorWritesPending; // nothing written anyway? (T127428)
} elseif ( $sql === 'ROLLBACK' ) {
}
/**
- * Clean things up after transaction loss due to disconnection
- *
- * @return null|Exception
+ * Clean things up after session (and thus transaction) loss
*/
private function handleSessionLoss() {
+ // Clean up tracking of session-level things...
+ // https://dev.mysql.com/doc/refman/5.7/en/implicit-commit.html
+ // https://www.postgresql.org/docs/9.1/static/sql-createtable.html (ignoring ON COMMIT)
+ $this->sessionTempTables = [];
+ // https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock
+ // https://www.postgresql.org/docs/9.4/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
+ $this->namedLocksHeld = [];
+ // Session loss implies transaction loss
+ $this->handleTransactionLoss();
+ }
+
+ /**
+ * Clean things up after transaction loss
+ */
+ private function handleTransactionLoss() {
$this->trxLevel = 0;
$this->trxAtomicCounter = 0;
$this->trxIdleCallbacks = []; // T67263; transaction already lost
$this->trxPreCommitCallbacks = []; // T67263; transaction already lost
- $this->sessionTempTables = [];
- $this->namedLocksHeld = [];
-
- // Note: if callback suppression is set then some *Callbacks arrays are not cleared here
- $e = null;
try {
- // Handle callbacks in trxEndCallbacks
+ // Handle callbacks in trxEndCallbacks, e.g. onTransactionResolution().
+ // If callback suppression is set then the array will remain unhandled.
$this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
} catch ( Exception $ex ) {
// Already logged; move on...
- $e = $e ?: $ex;
}
try {
- // Handle callbacks in trxRecurringCallbacks
+ // Handle callbacks in trxRecurringCallbacks, e.g. setTransactionListener()
$this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
} catch ( Exception $ex ) {
// Already logged; move on...
- $e = $e ?: $ex;
}
-
- return $e;
}
/**
return false;
}
+ /**
+ * Report a query error. Log the error, and if neither the object ignore
+ * flag nor the $tempIgnore flag is set, throw a DBQueryError.
+ *
+ * @param string $error
+ * @param int $errno
+ * @param string $sql
+ * @param string $fname
+ * @param bool $tempIgnore
+ * @throws DBQueryError
+ */
public function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
- if ( $this->ignoreErrors() || $tempIgnore ) {
+ if ( $tempIgnore ) {
$this->queryLogger->debug( "SQL ERROR (ignored): $error\n" );
} else {
$sql1line = mb_substr( str_replace( "\n", "\\n", $sql ), 0, 5 * 1024 );
}
try {
- $this->startAtomic( $fname );
+ $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
$affectedRowCount = 0;
foreach ( $rows as $row ) {
// Delete rows which collide with this one
$affectedRowCount = 0;
try {
- $this->startAtomic( $fname );
+ $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
# Update any existing conflicting row(s)
if ( $where !== false ) {
$ok = $this->update( $table, $set, $where, $fname );
try {
$affectedRowCount = 0;
- $this->startAtomic( $fname );
+ $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
$rows = [];
$ok = true;
foreach ( $res as $row ) {
}
final public function onTransactionIdle( callable $callback, $fname = __METHOD__ ) {
+ if ( !$this->trxLevel && $this->getTransactionRoundId() ) {
+ // Start an implicit transaction similar to how query() does
+ $this->begin( __METHOD__, self::TRANSACTION_INTERNAL );
+ $this->trxAutomatic = true;
+ }
+
$this->trxIdleCallbacks[] = [ $callback, $fname ];
if ( !$this->trxLevel ) {
$this->runOnTransactionIdleCallbacks( self::TRIGGER_IDLE );
}
final public function onTransactionPreCommitOrIdle( callable $callback, $fname = __METHOD__ ) {
- if ( $this->trxLevel || $this->getFlag( self::DBO_TRX ) ) {
- // As long as DBO_TRX is set, writes will accumulate until the load balancer issues
- // an implicit commit of all peer databases. This is true even if a transaction has
- // not yet been triggered by writes; make sure $callback runs *after* any such writes.
+ if ( !$this->trxLevel && $this->getTransactionRoundId() ) {
+ // Start an implicit transaction similar to how query() does
+ $this->begin( __METHOD__, self::TRANSACTION_INTERNAL );
+ $this->trxAutomatic = true;
+ }
+
+ if ( $this->trxLevel ) {
$this->trxPreCommitCallbacks[] = [ $callback, $fname ];
} else {
// No transaction is active nor will start implicitly, so make one for this callback
- $this->startAtomic( __METHOD__ );
+ $this->startAtomic( __METHOD__, self::ATOMIC_CANCELABLE );
try {
call_user_func( $callback );
$this->endAtomic( __METHOD__ );
$this->query( 'ROLLBACK TO SAVEPOINT ' . $this->addIdentifierQuotes( $identifier ), $fname );
}
- final public function startAtomic( $fname = __METHOD__ ) {
+ final public function startAtomic(
+ $fname = __METHOD__, $cancelable = self::ATOMIC_NOT_CANCELABLE
+ ) {
+ $savepointId = $cancelable === self::ATOMIC_CANCELABLE ? 'n/a' : null;
if ( !$this->trxLevel ) {
$this->begin( $fname, self::TRANSACTION_INTERNAL );
// If DBO_TRX is set, a series of startAtomic/endAtomic pairs will result
if ( !$this->getFlag( self::DBO_TRX ) ) {
$this->trxAutomaticAtomic = true;
}
- $savepointId = null;
- } else {
+ } elseif ( $cancelable === self::ATOMIC_CANCELABLE ) {
$savepointId = 'wikimedia_rdbms_atomic' . ++$this->trxAtomicCounter;
if ( strlen( $savepointId ) > 30 ) { // 30 == Oracle's identifier length limit (pre 12c)
$this->queryLogger->warning(
throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
}
- if ( !$savepointId ) {
+ if ( !$this->trxAtomicLevels && $this->trxAutomaticAtomic ) {
$this->commit( $fname, self::FLUSHING_INTERNAL );
- } else {
+ } elseif ( $savepointId && $savepointId !== 'n/a' ) {
$this->doReleaseSavepoint( $savepointId, $fname );
}
}
if ( $savedFname !== $fname ) {
throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
}
-
if ( !$savepointId ) {
+ throw new DBUnexpectedError( $this, "Uncancelable atomic section canceled (got $fname)." );
+ }
+
+ if ( !$this->trxAtomicLevels && $this->trxAutomaticAtomic ) {
$this->rollback( $fname, self::FLUSHING_INTERNAL );
- } else {
+ } elseif ( $savepointId !== 'n/a' ) {
$this->doRollbackToSavepoint( $savepointId, $fname );
}
}
final public function doAtomicSection( $fname, callable $callback ) {
- $this->startAtomic( $fname );
+ $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
try {
$res = call_user_func_array( $callback, [ $this, $fname ] );
} catch ( Exception $e ) {
$this->trxWriteAdjQueryCount = 0;
$this->trxWriteCallers = [];
// First SELECT after BEGIN will establish the snapshot in REPEATABLE-READ.
- // Get an estimate of the replica DB lag before then, treating estimate staleness
- // as lag itself just to be safe
- $status = $this->getApproximateLagStatus();
- $this->trxReplicaLag = $status['lag'] + ( microtime( true ) - $status['since'] );
+ // Get an estimate of the replication lag before any such queries.
+ $this->trxReplicaLag = $this->getApproximateLagStatus()['lag'];
// T147697: make explicitTrxActive() return true until begin() finishes. This way, no
// caller will think its OK to muck around with the transaction just because startAtomic()
// has not yet completed (e.g. setting trxAtomicLevels).
}
/**
- * Close existing database connection and open a new connection
+ * Close any existing (dead) database connection and open a new connection
*
+ * @param string $fname
* @return bool True if new connection is opened successfully, false if error
*/
- protected function reconnect() {
+ protected function replaceLostConnection( $fname ) {
$this->closeConnection();
$this->opened = false;
$this->conn = false;
$this->open( $this->server, $this->user, $this->password, $this->dbName );
$this->lastPing = microtime( true );
$ok = true;
+
+ $this->connLogger->warning(
+ $fname . ': lost connection to {dbserver}; reconnected',
+ [
+ 'dbserver' => $this->getServer(),
+ 'trace' => ( new RuntimeException() )->getTraceAsString()
+ ]
+ );
} catch ( DBConnectionError $e ) {
$ok = false;
+
+ $this->connLogger->error(
+ $fname . ': lost connection to {dbserver} permanently',
+ [ 'dbserver' => $this->getServer() ]
+ );
}
+ $this->handleSessionLoss();
+
return $ok;
}
* @return array|null ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
* @since 1.27
*/
- protected function getTransactionLagStatus() {
+ final protected function getTransactionLagStatus() {
return $this->trxLevel
? [ 'lag' => $this->trxReplicaLag, 'since' => $this->trxTimestamp() ]
: null;
dépôts / lhc / web / wiklou.git / blobdiff