use HashBagOStuff;
use LogicException;
use InvalidArgumentException;
+use UnexpectedValueException;
use Exception;
use RuntimeException;
* @see Database::trxLevel
*/
private $trxAutomatic = false;
+ /**
+ * Counter for atomic savepoint identifiers. Reset when a new transaction begins.
+ *
+ * @var int
+ */
+ private $trxAtomicCounter = 0;
/**
* Array of levels of atomicity within transactions
*
$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() {
- $this->trxLevel = 0;
- $this->trxIdleCallbacks = []; // T67263; transaction already lost
- $this->trxPreCommitCallbacks = []; // T67263; transaction already lost
+ // 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();
+ }
- // Note: if callback suppression is set then some *Callbacks arrays are not cleared here
- $e = null;
+ /**
+ * 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
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 );
}
public function estimateRowCount(
- $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+ $table, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
) {
+ $conds = $this->normalizeConditions( $conds, $fname );
+ $column = $this->extractSingleFieldFromList( $var );
+ if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
+ $conds[] = "$column IS NOT NULL";
+ }
+
$res = $this->select(
$table, [ 'rowcount' => 'COUNT(*)' ], $conds, $fname, $options, $join_conds
);
}
public function selectRowCount(
- $tables, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+ $tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
) {
- $rows = 0;
- $sql = $this->selectSQLText( $tables, '1', $conds, $fname, $options, $join_conds );
- // The identifier quotes is primarily for MSSQL.
- $rowCountCol = $this->addIdentifierQuotes( "rowcount" );
- $tableName = $this->addIdentifierQuotes( "tmp_count" );
- $res = $this->query( "SELECT COUNT(*) AS $rowCountCol FROM ($sql) $tableName", $fname );
+ $conds = $this->normalizeConditions( $conds, $fname );
+ $column = $this->extractSingleFieldFromList( $var );
+ if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
+ $conds[] = "$column IS NOT NULL";
+ }
- if ( $res ) {
- $row = $this->fetchRow( $res );
- $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
+ $res = $this->select(
+ [
+ 'tmp_count' => $this->buildSelectSubquery(
+ $tables,
+ '1',
+ $conds,
+ $fname,
+ $options,
+ $join_conds
+ )
+ ],
+ [ 'rowcount' => 'COUNT(*)' ],
+ [],
+ $fname
+ );
+ $row = $res ? $this->fetchRow( $res ) : [];
+
+ return isset( $row['rowcount'] ) ? (int)$row['rowcount'] : 0;
+ }
+
+ /**
+ * @param array|string $conds
+ * @param string $fname
+ * @return array
+ */
+ final protected function normalizeConditions( $conds, $fname ) {
+ if ( $conds === null || $conds === false ) {
+ $this->queryLogger->warning(
+ __METHOD__
+ . ' called from '
+ . $fname
+ . ' with incorrect parameters: $conds must be a string or an array'
+ );
+ $conds = '';
+ }
+
+ if ( !is_array( $conds ) ) {
+ $conds = ( $conds === '' ) ? [] : [ $conds ];
}
- return $rows;
+ return $conds;
+ }
+
+ /**
+ * @param array|string $var Field parameter in the style of select()
+ * @return string|null Column name or null; ignores aliases
+ * @throws DBUnexpectedError Errors out if multiple columns are given
+ */
+ final protected function extractSingleFieldFromList( $var ) {
+ if ( is_array( $var ) ) {
+ if ( !$var ) {
+ $column = null;
+ } elseif ( count( $var ) == 1 ) {
+ $column = isset( $var[0] ) ? $var[0] : reset( $var );
+ } else {
+ throw new DBUnexpectedError( $this, __METHOD__ . ': got multiple columns.' );
+ }
+ } else {
+ $column = $var;
+ }
+
+ return $column;
}
/**
return 'CAST( ' . $field . ' AS INTEGER )';
}
+ public function buildSelectSubquery(
+ $table, $vars, $conds = '', $fname = __METHOD__,
+ $options = [], $join_conds = []
+ ) {
+ return new Subquery(
+ $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds )
+ );
+ }
+
public function databasesAreIndependent() {
return false;
}
}
public function tableName( $name, $format = 'quoted' ) {
+ if ( $name instanceof Subquery ) {
+ throw new DBUnexpectedError(
+ $this,
+ __METHOD__ . ': got Subquery instance when expecting a string.'
+ );
+ }
+
# Skip the entire process when we have a string quoted on both ends.
# Note that we check the end so that we will still quote any use of
# use of `database`.table. But won't break things if someone wants
# any remote case where a word like on may be inside of a table name
# surrounded by symbols which may be considered word breaks.
if ( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
+ $this->queryLogger->warning(
+ __METHOD__ . ": use of subqueries is not supported this way.",
+ [ 'trace' => ( new RuntimeException() )->getTraceAsString() ]
+ );
+
return $name;
}
/**
* Get an aliased table name
- * e.g. tableName AS newTableName
*
- * @param string $name Table name, see tableName()
- * @param string|bool $alias Alias (optional)
+ * This returns strings like "tableName AS newTableName" for aliased tables
+ * and "(SELECT * from tableA) newTablename" for subqueries (e.g. derived tables)
+ *
+ * @see Database::tableName()
+ * @param string|Subquery $table Table name or object with a 'sql' field
+ * @param string|bool $alias Table alias (optional)
* @return string SQL name for aliased table. Will not alias a table to its own name
*/
- protected function tableNameWithAlias( $name, $alias = false ) {
- if ( !$alias || $alias == $name ) {
- return $this->tableName( $name );
+ protected function tableNameWithAlias( $table, $alias = false ) {
+ if ( is_string( $table ) ) {
+ $quotedTable = $this->tableName( $table );
+ } elseif ( $table instanceof Subquery ) {
+ $quotedTable = (string)$table;
} else {
- return $this->tableName( $name ) . ' ' . $this->addIdentifierQuotes( $alias );
+ throw new InvalidArgumentException( "Table must be a string or Subquery." );
+ }
+
+ if ( !strlen( $alias ) || $alias === $table ) {
+ if ( $table instanceof Subquery ) {
+ throw new InvalidArgumentException( "Subquery table missing alias." );
+ }
+
+ return $quotedTable;
+ } else {
+ return $quotedTable . ' ' . $this->addIdentifierQuotes( $alias );
}
}
}
try {
- $this->startAtomic( $fname );
+ $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
$affectedRowCount = 0;
foreach ( $rows as $row ) {
// Delete rows which collide with this one
$this->endAtomic( $fname );
$this->affectedRowCount = $affectedRowCount;
} catch ( Exception $e ) {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
}
$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 );
$this->endAtomic( $fname );
$this->affectedRowCount = $affectedRowCount;
} catch ( Exception $e ) {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
try {
$affectedRowCount = 0;
- $this->startAtomic( $fname );
+ $this->startAtomic( $fname, self::ATOMIC_CANCELABLE );
$rows = [];
$ok = true;
foreach ( $res as $row ) {
$this->endAtomic( $fname );
$this->affectedRowCount = $affectedRowCount;
} else {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
}
return $ok;
} catch ( Exception $e ) {
- $this->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
}
}
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__ );
} catch ( Exception $e ) {
- $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( __METHOD__ );
throw $e;
}
}
}
}
- final public function startAtomic( $fname = __METHOD__ ) {
+ /**
+ * Create a savepoint
+ *
+ * This is used internally to implement atomic sections. It should not be
+ * used otherwise.
+ *
+ * @since 1.31
+ * @param string $identifier Identifier for the savepoint
+ * @param string $fname Calling function name
+ */
+ protected function doSavepoint( $identifier, $fname ) {
+ $this->query( 'SAVEPOINT ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
+ /**
+ * Release a savepoint
+ *
+ * This is used internally to implement atomic sections. It should not be
+ * used otherwise.
+ *
+ * @since 1.31
+ * @param string $identifier Identifier for the savepoint
+ * @param string $fname Calling function name
+ */
+ protected function doReleaseSavepoint( $identifier, $fname ) {
+ $this->query( 'RELEASE SAVEPOINT ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
+ /**
+ * Rollback to a savepoint
+ *
+ * This is used internally to implement atomic sections. It should not be
+ * used otherwise.
+ *
+ * @since 1.31
+ * @param string $identifier Identifier for the savepoint
+ * @param string $fname Calling function name
+ */
+ protected function doRollbackToSavepoint( $identifier, $fname ) {
+ $this->query( 'ROLLBACK TO SAVEPOINT ' . $this->addIdentifierQuotes( $identifier ), $fname );
+ }
+
+ 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;
}
+ } 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(
+ 'There have been an excessively large number of atomic sections in a transaction'
+ . " started by $this->trxFname, reusing IDs (at $fname)",
+ [ 'trace' => ( new RuntimeException() )->getTraceAsString() ]
+ );
+ $this->trxAtomicCounter = 0;
+ $savepointId = 'wikimedia_rdbms_atomic' . ++$this->trxAtomicCounter;
+ }
+ $this->doSavepoint( $savepointId, $fname );
}
- $this->trxAtomicLevels[] = $fname;
+ $this->trxAtomicLevels[] = [ $fname, $savepointId ];
}
final public function endAtomic( $fname = __METHOD__ ) {
if ( !$this->trxLevel ) {
throw new DBUnexpectedError( $this, "No atomic transaction is open (got $fname)." );
}
- if ( !$this->trxAtomicLevels ||
- array_pop( $this->trxAtomicLevels ) !== $fname
- ) {
+
+ list( $savedFname, $savepointId ) = $this->trxAtomicLevels
+ ? array_pop( $this->trxAtomicLevels ) : [ null, null ];
+ if ( $savedFname !== $fname ) {
throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
}
if ( !$this->trxAtomicLevels && $this->trxAutomaticAtomic ) {
$this->commit( $fname, self::FLUSHING_INTERNAL );
+ } elseif ( $savepointId && $savepointId !== 'n/a' ) {
+ $this->doReleaseSavepoint( $savepointId, $fname );
+ }
+ }
+
+ final public function cancelAtomic( $fname = __METHOD__ ) {
+ if ( !$this->trxLevel ) {
+ throw new DBUnexpectedError( $this, "No atomic transaction is open (got $fname)." );
+ }
+
+ list( $savedFname, $savepointId ) = $this->trxAtomicLevels
+ ? array_pop( $this->trxAtomicLevels ) : [ null, null ];
+ 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 );
+ } elseif ( $savepointId !== 'n/a' ) {
+ $this->doRollbackToSavepoint( $savepointId, $fname );
}
+
+ $this->affectedRowCount = 0; // for the sake of consistency
}
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->rollback( $fname, self::FLUSHING_INTERNAL );
+ $this->cancelAtomic( $fname );
throw $e;
}
$this->endAtomic( $fname );
// Protect against mismatched atomic section, transaction nesting, and snapshot loss
if ( $this->trxLevel ) {
if ( $this->trxAtomicLevels ) {
- $levels = implode( ', ', $this->trxAtomicLevels );
+ $levels = array_reduce( $this->trxAtomicLevels, function ( $accum, $v ) {
+ return $accum === null ? $v[0] : "$accum, " . $v[0];
+ } );
$msg = "$fname: Got explicit BEGIN while atomic section(s) $levels are open.";
throw new DBUnexpectedError( $this, $msg );
} elseif ( !$this->trxAutomatic ) {
$msg = "$fname: Explicit transaction already active (from {$this->trxFname}).";
throw new DBUnexpectedError( $this, $msg );
} else {
- // @TODO: make this an exception at some point
$msg = "$fname: Implicit transaction already active (from {$this->trxFname}).";
- $this->queryLogger->error( $msg );
- return; // join the main transaction set
+ throw new DBUnexpectedError( $this, $msg );
}
} elseif ( $this->getFlag( self::DBO_TRX ) && $mode !== self::TRANSACTION_INTERNAL ) {
- // @TODO: make this an exception at some point
$msg = "$fname: Implicit transaction expected (DBO_TRX set).";
- $this->queryLogger->error( $msg );
- return; // let any writes be in the main transaction
+ throw new DBUnexpectedError( $this, $msg );
}
// Avoid fatals if close() was called
$this->assertOpen();
$this->doBegin( $fname );
+ $this->trxAtomicCounter = 0;
$this->trxTimestamp = microtime( true );
$this->trxFname = $fname;
$this->trxDoneWrites = false;
$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).
final public function commit( $fname = __METHOD__, $flush = '' ) {
if ( $this->trxLevel && $this->trxAtomicLevels ) {
// There are still atomic sections open. This cannot be ignored
- $levels = implode( ', ', $this->trxAtomicLevels );
+ $levels = array_reduce( $this->trxAtomicLevels, function ( $accum, $v ) {
+ return $accum === null ? $v[0] : "$accum, " . $v[0];
+ } );
throw new DBUnexpectedError(
$this,
"$fname: Got COMMIT while atomic sections $levels are still open."
"$fname: No transaction to commit, something got out of sync." );
return; // nothing to do
} elseif ( $this->trxAutomatic ) {
- // @TODO: make this an exception at some point
- $msg = "$fname: Explicit commit of implicit transaction.";
- $this->queryLogger->error( $msg );
- return; // wait for the main transaction set commit round
+ throw new DBUnexpectedError(
+ $this,
+ "$fname: Expected mass commit of all peer transactions (DBO_TRX set)."
+ );
}
}
}
final public function rollback( $fname = __METHOD__, $flush = '' ) {
- if ( $flush === self::FLUSHING_INTERNAL || $flush === self::FLUSHING_ALL_PEERS ) {
- if ( !$this->trxLevel ) {
- return; // nothing to do
- }
- } else {
- if ( !$this->trxLevel ) {
- $this->queryLogger->error(
- "$fname: No transaction to rollback, something got out of sync." );
- return; // nothing to do
- } elseif ( $this->getFlag( self::DBO_TRX ) ) {
+ $trxActive = $this->trxLevel;
+
+ if ( $flush !== self::FLUSHING_INTERNAL && $flush !== self::FLUSHING_ALL_PEERS ) {
+ if ( $this->getFlag( self::DBO_TRX ) ) {
throw new DBUnexpectedError(
$this,
- "$fname: Expected mass rollback of all peer databases (DBO_TRX set)."
+ "$fname: Expected mass rollback of all peer transactions (DBO_TRX set)."
);
}
}
- // Avoid fatals if close() was called
- $this->assertOpen();
+ if ( $trxActive ) {
+ // Avoid fatals if close() was called
+ $this->assertOpen();
- $this->doRollback( $fname );
- $this->trxAtomicLevels = [];
- if ( $this->trxDoneWrites ) {
- $this->trxProfiler->transactionWritingOut(
- $this->server,
- $this->dbName,
- $this->trxShortId
- );
+ $this->doRollback( $fname );
+ $this->trxAtomicLevels = [];
+ if ( $this->trxDoneWrites ) {
+ $this->trxProfiler->transactionWritingOut(
+ $this->server,
+ $this->dbName,
+ $this->trxShortId
+ );
+ }
}
- $this->trxIdleCallbacks = []; // clear
- $this->trxPreCommitCallbacks = []; // clear
- try {
- $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
- } catch ( Exception $e ) {
- // already logged; finish and let LoadBalancer move on during mass-rollback
- }
- try {
- $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
- } catch ( Exception $e ) {
- // already logged; let LoadBalancer move on during mass-rollback
- }
+ // Clear any commit-dependant callbacks. They might even be present
+ // only due to transaction rounds, with no SQL transaction being active
+ $this->trxIdleCallbacks = [];
+ $this->trxPreCommitCallbacks = [];
- $this->affectedRowCount = 0; // for the sake of consistency
+ if ( $trxActive ) {
+ try {
+ $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
+ } catch ( Exception $e ) {
+ // already logged; finish and let LoadBalancer move on during mass-rollback
+ }
+ try {
+ $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
+ } catch ( Exception $e ) {
+ // already logged; let LoadBalancer move on during mass-rollback
+ }
+
+ $this->affectedRowCount = 0; // for the sake of consistency
+ }
}
/**
}
/**
- * 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