Wikimedia\Rdbms\IDatabase Interface Reference

Basic database interface for live and lazy-loaded relation database handles. More...

Inheritance diagram for Wikimedia\Rdbms\IDatabase:

Collaboration diagram for Wikimedia\Rdbms\IDatabase:

Public Member Functions
	__toString ()
	Get a debugging string that mentions the database type, the ID of this instance, and the ID of any underlying connection resource or driver object if one is present.
	affectedRows ()
	Get the number of rows affected by the last write query.
	begin ( $fname=__METHOD__, $mode=self::TRANSACTION_EXPLICIT)
	Begin a transaction.
	cancelAtomic ( $fname=__METHOD__, AtomicSectionIdentifier $sectionId=null)
	Cancel an atomic section of SQL statements.
	clearFlag ( $flag, $remember=self::REMEMBER_NOTHING)
	Clear a flag for this connection.
	close ( $fname=__METHOD__)
	Close the database connection.
	commit ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
	Commits a transaction previously started using begin()
	databasesAreIndependent ()
	Returns true if DBs are assumed to be on potentially different servers.
	dbSchema ( $schema=null)
	Get/set the db schema.
	decodeBlob ( $b)
	Some DBMSs return a special placeholder object representing blob fields in result objects.
	delete ( $table, $conds, $fname=__METHOD__)
	Delete all rows in a table that match a condition.
	deleteJoin ( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname=__METHOD__)
	Delete all rows in a table that match a condition which includes a join.
	doAtomicSection ( $fname, callable $callback, $cancelable=self::ATOMIC_NOT_CANCELABLE)
	Perform an atomic section of reversible SQL statements from a callback.
	encodeBlob ( $b)
	Some DBMSs have a special format for inserting into blob fields, they don't allow simple quoted strings to be inserted.
	endAtomic ( $fname=__METHOD__)
	Ends an atomic section of SQL statements.
	estimateRowCount ( $tables, $var=' *', $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Estimate the number of rows in dataset.
	explicitTrxActive ()
	Check whether there is a transaction open at the specific request of a caller.
	flushSession ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
	Release important session-level state (named lock, table locks) as post-rollback cleanup.
	flushSnapshot ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
	Commit any transaction but error out if writes or callbacks are pending.
	getDBname ()
	Get the current database name; null if there isn't one.
	getDomainID ()
	Return the currently selected domain ID.
	getFlag ( $flag)
	Returns a boolean whether the flag $flag is set for this connection.
	getLag ()
	Get the amount of replication lag for this database server.
	getLBInfo ( $name=null)
	Get properties passed down from the server info array of the load balancer.
	getPrimaryPos ()
	Get the position of this primary DB.
	getReplicaPos ()
	Get the replication position of this replica DB.
	getScopedLockAndFlush ( $lockKey, $fname, $timeout)
	Acquire a named lock, flush any transaction, and return an RAII style unlocker object.
	getServer ()
	Get the hostname or IP address of the server.
	getServerInfo ()
	Get a human-readable string describing the current software version.
	getServerName ()
	Get the readable name for the server.
	getServerVersion ()
	A string describing the current software version, like from mysql_get_server_info()
	getSessionLagStatus ()
	Get the replica DB lag when the current transaction started or a general lag estimate if not transaction is active.
	getSoftwareLink ()
	Returns a wikitext style link to the DB's website (e.g.
	getTopologyBasedServerId ()
	Get a non-recycled ID that uniquely identifies this server within the replication topology.
	getTopologyRole ()
	Get the replication topology role of this server.
	getType ()
	Get the RDBMS type of the server (e.g.
	insert ( $table, $rows, $fname=__METHOD__, $options=[])
	Insert row(s) into a table, in the provided order.
	insertId ()
	Get the inserted value of an auto-increment row.
	insertSelect ( $destTable, $srcTable, $varMap, $conds, $fname=__METHOD__, $insertOptions=[], $selectOptions=[], $selectJoinConds=[])
	INSERT SELECT wrapper.
	isOpen ()
	isReadOnly ()
	lastDoneWrites ()
	Get the last time the connection may have been used for a write query.
	lastErrno ()
	Get the RDBMS-specific error code from the last query statement.
	lastError ()
	Get the RDBMS-specific error description from the last query statement.
	lastQuery ()
	Get the last query that sent on account of IDatabase::query()
	lock ( $lockName, $method, $timeout=5, $flags=0)
	Acquire a named lock.
	lockForUpdate ( $table, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Lock all rows meeting the given conditions/options FOR UPDATE.
	lockIsFree ( $lockName, $method)
	Check to see if a named lock is not locked by any thread (non-blocking)
	namedLocksEnqueue ()
	Check to see if a named lock used by lock() use blocking queues.
	newSelectQueryBuilder ()
	Create an empty SelectQueryBuilder which can be used to run queries against this connection.
	nextSequenceValue ( $seqName)
	Deprecated method, calls should be removed.
	onAtomicSectionCancel (callable $callback, $fname=__METHOD__)
	Run a callback when the atomic section is cancelled.
	onTransactionCommitOrIdle (callable $callback, $fname=__METHOD__)
	Run a callback when the current transaction commits or now if there is none.
	onTransactionPreCommitOrIdle (callable $callback, $fname=__METHOD__)
	Run a callback before the current transaction commits or now if there is none.
	onTransactionResolution (callable $callback, $fname=__METHOD__)
	Run a callback when the current transaction commits or rolls back.
	pendingWriteCallers ()
	Get the list of method names that did write queries for this transaction.
	pendingWriteQueryDuration ( $type=self::ESTIMATE_TOTAL)
	Get the time spend running write queries for this transaction.
	ping (&$rtt=null)
	Ping the server and try to reconnect if it there is no connection.
	primaryPosWait (DBPrimaryPos $pos, $timeout)
	Wait for the replica DB to catch up to a given primary DB position.
	query ( $sql, $fname=__METHOD__, $flags=0)
	Run an SQL query statement and return the result.
	queryMulti (array $sqls, string $fname=__METHOD__, int $flags=0, ?string $summarySql=null)
	Run a batch of SQL query statements and return the results.
	replace ( $table, $uniqueKeys, $rows, $fname=__METHOD__)
	Insert row(s) into a table, in the provided order, while deleting conflicting rows.
	restoreFlags ( $state=self::RESTORE_PRIOR)
	Restore the flags to their prior state before the last setFlag/clearFlag call.
	rollback ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
	Rollback a transaction previously started using begin()
	select ( $table, $vars, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Execute a SELECT query constructed using the various parameters provided.
	selectDB ( $db)
	Change the current database.
	selectDomain ( $domain)
	Set the current domain (database, schema, and table prefix)
	selectField ( $table, $var, $cond='', $fname=__METHOD__, $options=[], $join_conds=[])
	A SELECT wrapper which returns a single field from a single result row.
	selectFieldValues ( $table, $var, $cond='', $fname=__METHOD__, $options=[], $join_conds=[])
	A SELECT wrapper which returns a list of single field values from result rows.
	selectRow ( $table, $vars, $conds, $fname=__METHOD__, $options=[], $join_conds=[])
	Wrapper to IDatabase::select() that only fetches one row (via LIMIT)
	selectRowCount ( $tables, $var=' *', $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Get the number of rows in dataset.
	serverIsReadOnly ()
	setBigSelects ( $value=true)
	Allow or deny "big selects" for this session only.
	setFlag ( $flag, $remember=self::REMEMBER_NOTHING)
	Set a flag for this connection.
	setLBInfo ( $nameOrArray, $value=null)
	Set the entire array or a particular key of the managing load balancer info array.
	setSessionOptions (array $options)
	Override database's default behavior.
	setTransactionListener ( $name, callable $callback=null)
	Run a callback after each time any transaction commits or rolls back.
	startAtomic ( $fname=__METHOD__, $cancelable=self::ATOMIC_NOT_CANCELABLE)
	Begin an atomic section of SQL statements.
	tablePrefix ( $prefix=null)
	Get/set the table prefix.
	trxLevel ()
	Gets the current transaction level.
	trxTimestamp ()
	Get the UNIX timestamp of the time that the transaction was established.
	unlock ( $lockName, $method)
	Release a lock.
	update ( $table, $set, $conds, $fname=__METHOD__, $options=[])
	Update all rows in a table that match a given condition.
	upsert ( $table, array $rows, $uniqueKeys, array $set, $fname=__METHOD__)
	Upsert row(s) into a table, in the provided order, while updating conflicting rows.
	wasConnectionLoss ()
	Determines if the last query error was due to a dropped connection.
	wasDeadlock ()
	Determines if the last failure was due to a deadlock.
	wasErrorReissuable ()
	Determines if the last query error was due to something outside of the query itself.
	wasLockTimeout ()
	Determines if the last failure was due to a lock timeout.
	wasReadOnlyError ()
	Determines if the last failure was due to the database being read-only.
	writesOrCallbacksPending ()
	Whether there is a transaction open with either possible write queries or unresolved pre-commit/commit/resolution callbacks pending.
	writesPending ()
Public Member Functions inherited from Wikimedia\Rdbms\Platform\ISQLPlatform
	addIdentifierQuotes ( $s)
	Escape a SQL identifier (e.g.
	anyChar ()
	Returns a token for buildLike() that denotes a '_' to be used in a LIKE query.
	anyString ()
	Returns a token for buildLike() that denotes a '' to be used in a LIKE query.
	bitAnd ( $fieldLeft, $fieldRight)
	bitNot ( $field)
	bitOr ( $fieldLeft, $fieldRight)
	buildConcat ( $stringList)
	Build a concatenation list to feed into a SQL query.
	buildExcludedValue ( $column)
	Build a reference to a column value from the conflicting proposed upsert() row.
	buildGreatest ( $fields, $values)
	Build a GREATEST function statement comparing columns/values.
	buildGroupConcatField ( $delim, $table, $field, $conds='', $join_conds=[])
	Build a GROUP_CONCAT or equivalent statement for a query.
	buildIntegerCast ( $field)
	buildLeast ( $fields, $values)
	Build a LEAST function statement comparing columns/values.
	buildLike ( $param,... $params)
	LIKE statement wrapper.
	buildSelectSubquery ( $table, $vars, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Equivalent to IDatabase::selectSQLText() except wraps the result in Subquery.
	buildStringCast ( $field)
	buildSubString ( $input, $startPosition, $length=null)
	Build a SUBSTRING function.
	conditional ( $cond, $caseTrueExpression, $caseFalseExpression)
	Returns an SQL expression for a simple conditional.
	decodeExpiry ( $expiry, $format=TS_MW)
	Decode an expiry time into a DBMS independent format.
	encodeExpiry ( $expiry)
	Encode an expiry time into the DBMS dependent format.
	factorConds ( $condsArray)
	Given an array of condition arrays representing an OR list of AND lists, for example:
	getInfinity ()
	Find out when 'infinity' is.
	getTableAliases ()
	Return current table aliases.
	implicitOrderby ()
	Returns true if this database does an implicit order by when the column has an index For example: SELECT page_title FROM page LIMIT 1.
	limitResult ( $sql, $limit, $offset=false)
	Construct a LIMIT query with optional offset.
	makeList (array $a, $mode=self::LIST_COMMA)
	Makes an encoded list of strings from an array.
	makeWhereFrom2d ( $data, $baseKey, $subKey)
	Build a partial where clause from a 2-d array such as used for LinkBatch.
	selectSQLText ( $table, $vars, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Take the same arguments as IDatabase::select() and return the SQL it would use.
	setIndexAliases (array $aliases)
	Convert certain index names to alternative names before querying the DB.
	setSchemaVars ( $vars)
	Set schema variables to be used when streaming commands from SQL files or stdin.
	setTableAliases (array $aliases)
	Make certain table names use their own database, schema, and table prefix when passed into SQL queries pre-escaped and without a qualified database name.
	strreplace ( $orig, $old, $new)
	Returns a SQL expression for simple string replacement (e.g.
	tableName ( $name, $format='quoted')
	Format a table name ready for use in constructing an SQL query.
	tableNames (... $tables)
	Fetch a number of table names into an associative array.
	tableNamesN (... $tables)
	Fetch a number of table names into a zero-indexed numerical array.
	timestamp ( $ts=0)
	Convert a timestamp in one of the formats accepted by ConvertibleTimestamp to the format used for inserting into timestamp fields in this DBMS.
	timestampOrNull ( $ts=null)
	Convert a timestamp in one of the formats accepted by ConvertibleTimestamp to the format used for inserting into timestamp fields in this DBMS.
	unionConditionPermutations ( $table, $vars, array $permute_conds, $extra_conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Construct a UNION query for permutations of conditions.
	unionQueries ( $sqls, $all)
	Construct a UNION query.
	unionSupportsOrderAndLimit ()
	Determine if the RDBMS supports ORDER BY and LIMIT for separate subqueries within UNION.
Public Member Functions inherited from Wikimedia\Rdbms\Database\DbQuoter
	addQuotes ( $s)
	Escape and quote a raw value string for use in a SQL query.

Public Attributes
const	LOCK_TIMESTAMP = 1
	Flag to return the lock acquisition timestamp (null if not acquired)
Public Attributes inherited from Wikimedia\Rdbms\Platform\ISQLPlatform
const	QUERY_PSEUDO_PERMANENT = 2
	Track a TEMPORARY table CREATE as if it was for a permanent table (for testing)

Detailed Description

Basic database interface for live and lazy-loaded relation database handles.

Definition at line 39 of file IDatabase.php.

Member Function Documentation

__toString()

Wikimedia\Rdbms\IDatabase::__toString

(

)

Get a debugging string that mentions the database type, the ID of this instance, and the ID of any underlying connection resource or driver object if one is present.

Returns

string "<db type> object #<X>" or "<db type> object #<X> (resource/handle id #<Y>)"

Since

1.34

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

affectedRows()

Wikimedia\Rdbms\IDatabase::affectedRows

(

)

Get the number of rows affected by the last write query.

Similar to https://www.php.net/mysql_affected_rows but includes rows matched but not changed (ie. an UPDATE which sets all fields to the same value they already have). To get the old mysql_affected_rows behavior, include non-equality of the fields in WHERE.

Returns

int

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by User\addToDatabase(), MigrateComments\migrate(), MigrateActors\migrate(), MigrateActors\migrateLogSearch(), MigrateComments\migrateToTemp(), DeleteLocalPasswords\processUsers(), PopulateArchiveRevId\reassignArRevIds(), and User\saveSettings().

begin()

Wikimedia\Rdbms\IDatabase::begin	(		$fname = __METHOD__,
			$mode = self::TRANSACTION_EXPLICIT )

Begin a transaction.

Only call this from code with outer transaction scope. See https://www.mediawiki.org/wiki/Database_transactions for details. Nesting of transactions is not supported.

Note that when the DBO_TRX flag is set (which is usually the case for web requests, but not for maintenance scripts), any previous database query will have started a transaction automatically.

Nesting of transactions is not supported. Attempts to nest transactions will cause a warning, unless the current transaction was started automatically because of the DBO_TRX flag.

Parameters

string	$fname	Calling function name
string	$mode	A situationally valid IDatabase::TRANSACTION_* constant [optional]

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\DBConnRef, and Wikimedia\Rdbms\Database.

Referenced by Maintenance\beginTransaction().

cancelAtomic()

Wikimedia\Rdbms\IDatabase::cancelAtomic	(		$fname = __METHOD__,
		AtomicSectionIdentifier	$sectionId = null )

Cancel an atomic section of SQL statements.

This will roll back only the statements executed since the start of the most recent atomic section, and close that section. If a transaction was open before the corresponding startAtomic() call, any statements before that call are not rolled back and the transaction remains open. If the corresponding startAtomic() implicitly started a transaction, that transaction is rolled back.

Note

callers must use additional measures for situations involving two or more (peer) transactions (e.g. updating two database servers at once). The transaction and savepoint logic of startAtomic() are bound to specific IDatabase instances.

Note that a call to IDatabase::rollback() will also roll back any open atomic sections.

Note

As a micro-optimization to save a few DB calls, this method may only be called when startAtomic() was called with the ATOMIC_CANCELABLE flag.

Since

1.31

See also

IDatabase::startAtomic

Parameters

string	$fname
AtomicSectionIdentifier | null	$sectionId	Section ID from startAtomic(); passing this enables cancellation of unclosed nested sections [optional]

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

clearFlag()

Wikimedia\Rdbms\IDatabase::clearFlag	(		$flag,
			$remember = self::REMEMBER_NOTHING )

Clear a flag for this connection.

Parameters

int	$flag	One of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX)
string	$remember	IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

close()

Wikimedia\Rdbms\IDatabase::close

(

$fname = __METHOD__

)

Close the database connection.

This should only be called after any transactions have been resolved, aside from read-only automatic transactions (assuming no callbacks are registered). If a transaction is still open anyway, it will be rolled back.

Access: internal

Only for use by LoadBalancer

Parameters

string

$fname

Caller name

Returns

bool Success

Exceptions

DBError

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\LoadBalancer\closeConnection().

commit()

Wikimedia\Rdbms\IDatabase::commit	(		$fname = __METHOD__,
			$flush = self::FLUSHING_ONE )

Commits a transaction previously started using begin()

If no transaction is in progress, a warning is issued.

Only call this from code with outer transaction scope. See https://www.mediawiki.org/wiki/Database_transactions for details. Nesting of transactions is not supported.

Parameters

string	$fname
string	$flush	Flush flag, set to situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly committing implicit transactions, or calling commit when no transaction is in progress. This will trigger an exception if there is an ongoing explicit transaction. Only set the flush flag if you are sure that these warnings are not applicable, and no explicit transactions are open.

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Maintenance\commitTransaction().

databasesAreIndependent()

Wikimedia\Rdbms\IDatabase::databasesAreIndependent

(

)

Returns true if DBs are assumed to be on potentially different servers.

In systems like mysql/mariadb, different databases can easily be referenced on a single connection merely by name, even in a single query via JOIN. On the other hand, Postgres treats databases as logically separate, with different database users, requiring special mechanisms like postgres_fdw to "mount" foreign DBs. This is true even among DBs on the same server. Changing the selected database via selectDomain() requires a new connection.

Returns

bool

Since

1.29

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

dbSchema()

Wikimedia\Rdbms\IDatabase::dbSchema

(

$schema = null

)

Get/set the db schema.

Parameters

string | null

$schema

The database schema to set, or omitted to leave it unchanged

Returns

string The previous db schema

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

decodeBlob()

Wikimedia\Rdbms\IDatabase::decodeBlob

(

$b

)

Some DBMSs return a special placeholder object representing blob fields in result objects.

Pass the object through this function to return the original string.

Parameters

string | Blob

$b

Returns

string

Exceptions

DBError

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by ArchivedFile\loadMetadataFromDbFieldValue(), and LocalFile\loadMetadataFromDbFieldValue().

delete()

Wikimedia\Rdbms\IDatabase::delete	(		$table,
			$conds,
			$fname = __METHOD__ )

Delete all rows in a table that match a condition.

Parameters

string	$table	Table name
string | array	$conds	Array of conditions. See $conds in IDatabase::select() In order to prevent possible performance or replication issues or damaging a data accidentally, an empty condition for 'delete' queries isn't allowed. IDatabase::ALL_ROWS should be passed explicitly in order to delete all rows.
string	$fname	Name of the calling function

Returns

bool Return true if no exception was thrown (deprecated since 1.33)

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by PopulateArchiveRevId\checkMysqlAutoIncrementBug(), SqlBagOStuff\deleteAll(), MediaWiki\Deferred\LinksUpdate\LinksTable\doWrites(), LCStoreDB\finishWrite(), MigrateActors\migrateLogSearch(), MediaWiki\Block\DatabaseBlockStore\purgeExpiredBlocks(), Title\purgeExpiredRestrictions(), PopulateArchiveRevId\reassignArRevIds(), and QueryPage\recache().

deleteJoin()

Wikimedia\Rdbms\IDatabase::deleteJoin	(		$delTable,
			$joinTable,
			$delVar,
			$joinVar,
			$conds,
			$fname = __METHOD__ )

Delete all rows in a table that match a condition which includes a join.

For safety, an empty $conds will not delete everything. If you want to delete all rows where the join condition matches, set $conds=IDatabase::ALL_ROWS.

DO NOT put the join condition in $conds.

Parameters

string	$delTable	The table to delete from.
string	$joinTable	The other table.
string	$delVar	The variable to join on, in the first table.
string	$joinVar	The variable to join on, in the second table.
array | string	$conds	Condition array of field names mapped to variables, ANDed together in the WHERE clause
string	$fname	Calling function name (use METHOD) for logs/profiling

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

doAtomicSection()

Wikimedia\Rdbms\IDatabase::doAtomicSection	(		$fname,
		callable	$callback,
			$cancelable = self::ATOMIC_NOT_CANCELABLE )

Perform an atomic section of reversible SQL statements from a callback.

The $callback takes the following arguments:

• This database object
• The value of $fname

This will execute the callback inside a pair of startAtomic()/endAtomic() calls. If any exception occurs during execution of the callback, it will be handled as follows:

• If $cancelable is ATOMIC_CANCELABLE, cancelAtomic() will be called to back out any (and only) statements executed during the atomic section. If that succeeds, then the exception will be re-thrown; if it fails, then a different exception will be thrown and any further query attempts will fail until rollback() is called.
• If $cancelable is ATOMIC_NOT_CANCELABLE, cancelAtomic() will be called to mark the end of the section and the error will be re-thrown. Any further query attempts will fail until rollback() is called.

This method is convenient for letting calls to the caller of this method be wrapped in a try/catch blocks for exception types that imply that the caller failed but was able to properly discard the changes it made in the transaction. This method can be an alternative to explicit calls to startAtomic()/endAtomic()/cancelAtomic().

Example usage, "RecordStore::save" method:

$dbw->doAtomicSection( __METHOD__, function ( $dbw ) use ( $record ) {
    // Create new record metadata row
    $dbw->insert( 'records', $record->toArray(), __METHOD__ );
    // Figure out where to store the data based on the new row's ID
    $path = $this->recordDirectory . '/' . $dbw->insertId();
    // Write the record data to the storage system;
    // blob store throws StoreFailureException on failure
    $this->blobStore->create( $path, $record->getJSON() );
    // Try to cleanup files orphaned by transaction rollback
    $dbw->onTransactionResolution(
        function ( $type ) use ( $path ) {
            if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
                $this->blobStore->delete( $path );
            }
        },
        __METHOD__
     );
}, $dbw::ATOMIC_CANCELABLE );

Example usage, caller of the "RecordStore::save" method:

$dbw->startAtomic( __METHOD__ );
// ...various SQL writes happen...
try {
    $recordStore->save( $record );
} catch ( StoreFailureException $e ) {
    // ...various SQL writes happen...
}
// ...various SQL writes happen...
$dbw->endAtomic( __METHOD__ );

See also

Database::startAtomic

Database::endAtomic

Database::cancelAtomic

Parameters

string	$fname	Caller name (usually METHOD)
callable	$callback	Callback that issues DB updates
string	$cancelable	Pass self::ATOMIC_CANCELABLE to use a savepoint and enable self::cancelAtomic() for this section.

Returns

mixed Result of the callback (since 1.28)

Exceptions

DBError

If an error occurs, {

See also

query}

Exceptions

Exception

If an error occurs in the callback

Since

1.27; prior to 1.31 this did a rollback() instead of cancelAtomic(), and assumed no callers up the stack would ever try to catch the exception.

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by User\addToDatabase(), PopulateArchiveRevId\checkMysqlAutoIncrementBug(), MediaWiki\Revision\RevisionStore\insertRevisionOn(), and PopulateArchiveRevId\reassignArRevIds().

encodeBlob()

Wikimedia\Rdbms\IDatabase::encodeBlob

(

$b

)

Some DBMSs have a special format for inserting into blob fields, they don't allow simple quoted strings to be inserted.

To insert into such a field, pass the data through this function before passing it to IDatabase::insert().

Parameters

string

$b

Returns

string|Blob

Exceptions

DBError

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by ArchivedFile\getMetadataForDb(), LocalFile\getMetadataForDb(), and LCStoreDB\set().

endAtomic()

Wikimedia\Rdbms\IDatabase::endAtomic

(

$fname = __METHOD__

)

Ends an atomic section of SQL statements.

Ends the next section of atomic SQL statements and commits the transaction if necessary.

Since

1.23

See also

IDatabase::startAtomic

Parameters

string

$fname

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by JobQueueDB\doBatchPushInternal(), and LCStoreDB\finishWrite().

estimateRowCount()

Wikimedia\Rdbms\IDatabase::estimateRowCount	(		$tables,
			$var = ' *',
			$conds = '',
			$fname = __METHOD__,
			$options = [],
			$join_conds = [] )

Estimate the number of rows in dataset.

MySQL allows you to estimate the number of rows that would be returned by a SELECT query, using EXPLAIN SELECT. The estimate is provided using index cardinality statistics, and is notoriously inaccurate, especially when large numbers of rows have recently been added or deleted.

For DBMSs that don't support fast result size estimation, this function will actually perform the SELECT COUNT(*).

Takes the same arguments as IDatabase::select().

New callers should use newSelectQueryBuilder with SelectQueryBuilder::estimateRowCount instead, which is more readable and less error-prone.

Parameters

string | string[]	$tables	Table name(s)
string	$var	Column for which NULL values are not counted [default "*"]
array | string	$conds	Filters on the table
string	$fname	Function name for profiling
array	$options	Options for select
array | string	$join_conds	Join conditions

Returns

int Row count

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, and Wikimedia\Rdbms\DBConnRef.

explicitTrxActive()

Wikimedia\Rdbms\IDatabase::explicitTrxActive

(

)

Check whether there is a transaction open at the specific request of a caller.

Explicit transactions are spawned by begin(), startAtomic(), and doAtomicSection(). Note that explicit transactions should not be confused with explicit transaction rounds.

Returns

bool

Since

1.28

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

flushSession()

Wikimedia\Rdbms\IDatabase::flushSession	(		$fname = __METHOD__,
			$flush = self::FLUSHING_ONE )

Release important session-level state (named lock, table locks) as post-rollback cleanup.

This should only be called by a load balancer or if the handle is not attached to one. Also, there must be no chance that a future caller will still be expecting some of the lost session state.

Connection and query errors will be suppressed and logged

Parameters

string	$fname	Calling function name
string	$flush	Flush flag, set to a situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly rolling back implicit transactions. This will silently break any ongoing explicit transaction. Only set the flush flag if you are sure that it is safe to ignore these warnings in your context.

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.38

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

flushSnapshot()

Wikimedia\Rdbms\IDatabase::flushSnapshot	(		$fname = __METHOD__,
			$flush = self::FLUSHING_ONE )

Commit any transaction but error out if writes or callbacks are pending.

This is intended for clearing out REPEATABLE-READ snapshots so that callers can see a new point-in-time of the database. This is useful when one of many transaction rounds finished and significant time will pass in the script's lifetime. It is also useful to call on a replica DB after waiting on replication to catch up to the primary DB.

Parameters

string	$fname	Calling function name
string	$flush	Flush flag, set to situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly committing implicit transactions, or calling commit when no transaction is in progress. This will trigger an exception if there is an ongoing explicit transaction. Only set the flush flag if you are sure that these warnings are not applicable, and no explicit transactions are open.

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.28

1.34 Added $flush parameter

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getDBname()

Wikimedia\Rdbms\IDatabase::getDBname

(

)

Get the current database name; null if there isn't one.

Returns

string|null

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getDomainID()

Wikimedia\Rdbms\IDatabase::getDomainID

(

)

Return the currently selected domain ID.

Null components (database/schema) might change once a connection is established

Returns

string

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\LoadBalancer\closeConnection(), MediaWiki\Deferred\LinksUpdate\LinksTable\doWrites(), Wikimedia\Rdbms\LoadBalancer\getConnLogContext(), ActorMigrationBase\getInsertValues(), ActorMigrationBase\getInsertValuesWithTempTable(), ActorMigrationBase\getWhere(), Title\invalidateCache(), Wikimedia\Rdbms\LBFactorySingle\newFromConnection(), Wikimedia\Rdbms\LoadBalancerSingle\newFromConnection(), MediaWiki\ResourceLoader\WikiModule\preloadTitleInfo(), Wikimedia\Rdbms\LoadBalancer\reuseConnectionInternal(), and Wikimedia\Rdbms\TransactionManager\transactionWritingOut().

getFlag()

Wikimedia\Rdbms\IDatabase::getFlag

(

$flag

)

Returns a boolean whether the flag $flag is set for this connection.

Parameters

int

$flag

One of the class IDatabase::DBO_* constants

Returns

bool

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getLag()

Wikimedia\Rdbms\IDatabase::getLag

(

)

Get the amount of replication lag for this database server.

Callers should avoid using this method while a transaction is active

Returns

float|int|false Database replication lag in seconds or false on error

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getLBInfo()

Wikimedia\Rdbms\IDatabase::getLBInfo

(

$name = null

)

Get properties passed down from the server info array of the load balancer.

Parameters

string | null

$name

The entry of the info array to get, or null to get the whole array

Returns

array|mixed|null

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\LoadBalancer\closeConnection(), Wikimedia\Rdbms\LoadBalancer\reuseConnectionInternal(), and Wikimedia\Rdbms\LoadBalancer\waitForPrimaryPos().

getPrimaryPos()

Wikimedia\Rdbms\IDatabase::getPrimaryPos

(

)

Get the position of this primary DB.

Returns

DBPrimaryPos|false False if this is not a primary DB

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.37

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, and Wikimedia\Rdbms\DBConnRef.

getReplicaPos()

Wikimedia\Rdbms\IDatabase::getReplicaPos

(

)

Get the replication position of this replica DB.

Returns

DBPrimaryPos|false False if this is not a replica DB

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, and Wikimedia\Rdbms\DBConnRef.

getScopedLockAndFlush()

Wikimedia\Rdbms\IDatabase::getScopedLockAndFlush	(		$lockKey,
			$fname,
			$timeout )

Acquire a named lock, flush any transaction, and return an RAII style unlocker object.

Only call this from outer transaction scope and when only one DB will be affected. See https://www.mediawiki.org/wiki/Database_transactions for details.

This is suitable for transactions that need to be serialized using cooperative locks, where each transaction can see each others' changes. Any transaction is flushed to clear out stale REPEATABLE-READ snapshot data. Once the returned object falls out of PHP scope, the lock will be released unless a transaction is active. If one is active, then the lock will be released when it either commits or rolls back.

If the lock acquisition failed, then no transaction flush happens, and null is returned.

Parameters

string	$lockKey	Name of lock to release
string	$fname	Name of the calling method
int	$timeout	Acquisition timeout in seconds

Returns

ScopedCallback|null

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.27

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by MediaWiki\Deferred\LinksUpdate\LinksUpdate\acquirePageLock().

getServer()

Wikimedia\Rdbms\IDatabase::getServer

(

)

Get the hostname or IP address of the server.

Returns

string|null

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getServerInfo()

Wikimedia\Rdbms\IDatabase::getServerInfo

(

)

Get a human-readable string describing the current software version.

Use getServerVersion() to get machine-friendly information.

Returns

string Version information from the database server

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getServerName()

Wikimedia\Rdbms\IDatabase::getServerName

(

)

Get the readable name for the server.

Returns

string Readable server name, falling back to the hostname or IP address

Since

1.36

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\DBQueryError\__construct(), Wikimedia\Rdbms\LoadBalancer\getConnLogContext(), and Wikimedia\Rdbms\TransactionManager\transactionWritingOut().

getServerVersion()

Wikimedia\Rdbms\IDatabase::getServerVersion

(

)

A string describing the current software version, like from mysql_get_server_info()

Returns

string Version information from the database server.

Implemented in Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\Database\getServerInfo(), and DatabaseInstaller\meetsMinimumRequirement().

getSessionLagStatus()

Wikimedia\Rdbms\IDatabase::getSessionLagStatus

(

)

Get the replica DB lag when the current transaction started or a general lag estimate if not transaction is active.

This is useful when transactions might use snapshot isolation (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data is this lag plus transaction duration. If they don't, it is still safe to be pessimistic. In AUTOCOMMIT mode, this still gives an indication of the staleness of subsequent reads.

Returns

array ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.27

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getSoftwareLink()

Wikimedia\Rdbms\IDatabase::getSoftwareLink

(

)

Returns a wikitext style link to the DB's website (e.g.

"[https://www.mysql.com/ MySQL]")

Should at least contain plain text, if for some reason your database has no website.

Returns

string Wikitext of a link to the server software's web site

Implemented in Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by MysqlInstaller\meetsMinimumRequirement().

getTopologyBasedServerId()

Wikimedia\Rdbms\IDatabase::getTopologyBasedServerId

(

)

Get a non-recycled ID that uniquely identifies this server within the replication topology.

A replication topology defines which servers can originate changes to a given dataset and how those changes propagate among database servers. It is assumed that the server only participates in the replication of a single relevant dataset.

Returns

string|null 32, 64, or 128 bit integer ID; null if not applicable or unknown

Exceptions

DBQueryError

Since

1.37

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

getTopologyRole()

Wikimedia\Rdbms\IDatabase::getTopologyRole

(

)

Get the replication topology role of this server.

A replication topology defines which servers can originate changes to a given dataset and how those changes propagate among database servers. It is assumed that the server only participates in the replication of a single relevant dataset.

Returns

string One of the class ROLE_* constants

Exceptions

DBQueryError

Since

1.34

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

getType()

Wikimedia\Rdbms\IDatabase::getType

(

)

Get the RDBMS type of the server (e.g.

"mysql", "sqlite")

Returns

string

Implemented in Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by PopulateArchiveRevId\checkMysqlAutoIncrementBug(), Wikimedia\Rdbms\SelectQueryBuilder\connection(), SqlBagOStuff\createTables(), DatabaseUpdater\newForDB(), and DatabaseUpdater\patchPath().

insert()

Wikimedia\Rdbms\IDatabase::insert	(		$table,
			$rows,
			$fname = __METHOD__,
			$options = [] )

Insert row(s) into a table, in the provided order.

Parameters

string	$table	Table name
array | array[]	$rows	Row(s) to insert, as either: A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. An integer-keyed list of such string-keyed maps, defining a list of new rows. The keys in each map must be identical to each other and in the same order. The rows must not collide with each other.
string	$fname	Calling function name (use METHOD) for logs/profiling
string | array	$options	Combination map/list where each string-keyed entry maps a non-boolean option to the option parameters and each integer-keyed value is the name of a boolean option. Supported options are: IGNORE: Boolean: skip insertion of rows that would cause unique key conflicts. IDatabase::affectedRows() can be used to determine how many rows were inserted.

Returns

bool Return true if no exception was thrown (deprecated since 1.33)

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by User\addToDatabase(), PopulateArchiveRevId\checkMysqlAutoIncrementBug(), CommentStore\createComment(), JobQueueDB\doBatchPushInternal(), MediaWiki\Deferred\LinksUpdate\LinksTable\doWrites(), LCStoreDB\finishWrite(), MigrateActors\migrateLogSearch(), MigrateComments\migrateToTemp(), PopulateArchiveRevId\reassignArRevIds(), and QueryPage\recache().

insertId()

Wikimedia\Rdbms\IDatabase::insertId

(

)

Get the inserted value of an auto-increment row.

This should only be called after an insert that used an auto-incremented value. If no such insert was previously done in the current database session, the return value is undefined.

Returns

int

Implemented in Wikimedia\Rdbms\DatabaseMysqli, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by User\addToDatabase(), PopulateArchiveRevId\checkMysqlAutoIncrementBug(), and CommentStore\createComment().

insertSelect()

Wikimedia\Rdbms\IDatabase::insertSelect	(		$destTable,
			$srcTable,
			$varMap,
			$conds,
			$fname = __METHOD__,
			$insertOptions = [],
			$selectOptions = [],
			$selectJoinConds = [] )

INSERT SELECT wrapper.

Warning

If the insert will use an auto-increment or sequence to determine the value of a column, this may break replication on databases using statement-based replication if the SELECT is not deterministically ordered.

Parameters

string	$destTable	The table name to insert into
string | array	$srcTable	May be either a table name, or an array of table names to include in a join.
array	$varMap	Must be an associative array of the form [ 'dest1' => 'source1', ... ]. Source items may be literals rather than field names, but strings should be quoted with IDatabase::addQuotes()
array	$conds	Condition array. See $conds in IDatabase::select() for the details of the format of condition arrays. May be "*" to copy the whole table.
string	$fname	The function name of the caller, from METHOD
array	$insertOptions	Options for the INSERT part of the query, see IDatabase::insert() for details. Also, one additional option is available: pass 'NO_AUTO_COLUMNS' to hint that the query does not use an auto-increment or sequence to determine any column values.
array	$selectOptions	Options for the SELECT part of the query, see IDatabase::select() for details.
array	$selectJoinConds	Join conditions for the SELECT part of the query, see IDatabase::select() for details.

Returns

bool Return true if no exception was thrown (deprecated since 1.33)

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

isOpen()

Wikimedia\Rdbms\IDatabase::isOpen

(

)

Returns

bool Whether a connection to the database open

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

isReadOnly()

Wikimedia\Rdbms\IDatabase::isReadOnly

(

)

Returns

bool Whether this DB is read-only

Since

1.27

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by LCStoreDB\startWrite().

lastDoneWrites()

Wikimedia\Rdbms\IDatabase::lastDoneWrites

(

)

Get the last time the connection may have been used for a write query.

Returns

int|float|false UNIX timestamp or false

Since

1.24

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

lastErrno()

Wikimedia\Rdbms\IDatabase::lastErrno

(

)

Get the RDBMS-specific error code from the last query statement.

Returns

int|string Error code (integer or hexadecimal depending on RDBMS type)

Implemented in Wikimedia\Rdbms\DatabaseMysqli, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\DatabaseMysqlBase\wasDeadlock(), Wikimedia\Rdbms\DatabaseMysqlBase\wasLockTimeout(), and Wikimedia\Rdbms\DatabaseMysqlBase\wasReadOnlyError().

lastError()

Wikimedia\Rdbms\IDatabase::lastError

(

)

Get the RDBMS-specific error description from the last query statement.

Returns

string

Implemented in Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

lastQuery()

Wikimedia\Rdbms\IDatabase::lastQuery

(

)

Get the last query that sent on account of IDatabase::query()

Returns

string SQL text or empty string if there was no such query

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

lock()

Wikimedia\Rdbms\IDatabase::lock	(		$lockName,
			$method,
			$timeout = 5,
			$flags = 0 )

Acquire a named lock.

Named locks are not related to transactions

Parameters

string	$lockName	Name of lock to acquire
string	$method	Name of the calling method
int	$timeout	Acquisition timeout in seconds (0 means non-blocking)
int	$flags	Bit field of IDatabase::LOCK_* constants

Returns

bool|float|null Success (bool); acquisition time (float/null) if LOCK_TIMESTAMP

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by SqlBagOStuff\doLock().

lockForUpdate()

Wikimedia\Rdbms\IDatabase::lockForUpdate	(		$table,
			$conds = '',
			$fname = __METHOD__,
			$options = [],
			$join_conds = [] )

Lock all rows meeting the given conditions/options FOR UPDATE.

Parameters

string | string[]	$table	Table name(s)
array | string	$conds	Filters on the table
string	$fname	Function name for profiling
array	$options	Options for select ("FOR UPDATE" is added automatically)
array	$join_conds	Join conditions

Returns

int Number of matching rows found (and locked)

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.32

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by LocalFileMoveBatch\verifyDBUpdates().

lockIsFree()

Wikimedia\Rdbms\IDatabase::lockIsFree	(		$lockName,
			$method )

Check to see if a named lock is not locked by any thread (non-blocking)

Parameters

string	$lockName	Name of lock to poll
string	$method	Name of method calling us

Returns

bool

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.20

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

namedLocksEnqueue()

Wikimedia\Rdbms\IDatabase::namedLocksEnqueue

(

)

Check to see if a named lock used by lock() use blocking queues.

Returns

bool

Since

1.26

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, and Wikimedia\Rdbms\DBConnRef.

newSelectQueryBuilder()

Wikimedia\Rdbms\IDatabase::newSelectQueryBuilder

(

)

Create an empty SelectQueryBuilder which can be used to run queries against this connection.

Note

A new query builder must be created per query. Query builders should not be reused since this uses a fluent interface and the state of the builder changes during the query which may cause unexpected results.

Returns

SelectQueryBuilder

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by ChangeTags\getTagsWithData().

nextSequenceValue()

Wikimedia\Rdbms\IDatabase::nextSequenceValue

(

$seqName

)

Deprecated method, calls should be removed.

This was formerly used for PostgreSQL to handle self::insertId() auto-incrementing fields. It is no longer necessary since DatabasePostgres::insertId() has been reimplemented using lastval()

Implementations should return null if inserting NULL into an auto-incrementing field works, otherwise it should return an instance of NextSequenceValue and filter it on calls to relevant methods.

Deprecated

since 1.30, no longer needed

Parameters

string

$seqName

Returns

null|NextSequenceValue

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabasePostgres, and Wikimedia\Rdbms\DBConnRef.

onAtomicSectionCancel()

Wikimedia\Rdbms\IDatabase::onAtomicSectionCancel	(	callable	$callback,
			$fname = __METHOD__ )

Run a callback when the atomic section is cancelled.

The callback is run just after the current atomic section, any outer atomic section, or the whole transaction is rolled back.

An error is thrown if no atomic section is pending. The atomic section need not have been created with the ATOMIC_CANCELABLE flag.

Queries in the function may be running in the context of an outer transaction or may be running in AUTOCOMMIT mode. The callback should use atomic sections if necessary.

Note

do not assume that other IDatabase instances will be AUTOCOMMIT mode

The callback takes the following arguments:

• IDatabase::TRIGGER_CANCEL or IDatabase::TRIGGER_ROLLBACK
• This IDatabase instance

Parameters

callable	$callback
string	$fname	Caller name

Since

1.34

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

onTransactionCommitOrIdle()

Wikimedia\Rdbms\IDatabase::onTransactionCommitOrIdle	(	callable	$callback,
			$fname = __METHOD__ )

Run a callback when the current transaction commits or now if there is none.

If there is a transaction and it is rolled back, then the callback is cancelled.

When transaction round mode (DBO_TRX) is set, the callback will run at the end of the round, just after all peer transactions COMMIT. If the transaction round is rolled back, then the callback is cancelled.

This IDatabase instance will start off in auto-commit mode when the callback starts. The use of other IDatabase handles from the callback should be avoided unless they are known to be in auto-commit mode. Callbacks that create transactions via begin() or startAtomic() must have matching calls to commit()/endAtomic().

Use this method only for the following purposes:

• (a) RDBMS updates, prone to lock timeouts/deadlocks, that do not require atomicity with respect to the updates in the current transaction (if any)
• (b) Purges to lightweight cache services due to RDBMS updates
• (c) Updates to secondary DBs/stores that must only commit once the updates in the current transaction (if any) are committed (e.g. insert user account row to DB1, then, initialize corresponding LDAP account)

The callback takes the following arguments:

• How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_IDLE)
• This IDatabase instance (since 1.32)

Callbacks will execute in the order they were enqueued.

Parameters

callable	$callback
string	$fname	Caller name

Exceptions

DBError

If an error occurs, {

See also

query}

Exceptions

Exception

If the callback runs immediately and an error occurs in it

Since

1.32

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

onTransactionPreCommitOrIdle()

Wikimedia\Rdbms\IDatabase::onTransactionPreCommitOrIdle	(	callable	$callback,
			$fname = __METHOD__ )

Run a callback before the current transaction commits or now if there is none.

If there is a transaction and it is rolled back, then the callback is cancelled.

When transaction round mode (DBO_TRX) is set, the callback will run at the end of the round, just after all peer transactions COMMIT. If the transaction round is rolled back, then the callback is cancelled.

If there is no current transaction, one will be created to wrap the callback. Callbacks cannot use begin()/commit() to manage transactions. The use of other IDatabase handles from the callback should be avoided.

Use this method only for the following purposes:

• a) RDBMS updates, prone to lock timeouts/deadlocks, that require atomicity with respect to the updates in the current transaction (if any)
• b) Purges to lightweight cache services due to RDBMS updates

The callback takes the one argument:

• This IDatabase instance (since 1.32)

Callbacks will execute in the order they were enqueued.

Parameters

callable	$callback
string	$fname	Caller name

Exceptions

DBError

If an error occurs, {

See also

query}

Exceptions

Exception

If the callback runs immediately and an error occurs in it

Since

1.22

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

onTransactionResolution()

Wikimedia\Rdbms\IDatabase::onTransactionResolution	(	callable	$callback,
			$fname = __METHOD__ )

Run a callback when the current transaction commits or rolls back.

An error is thrown if no transaction is pending.

When transaction round mode (DBO_TRX) is set, the callback will run at the end of the round, just after all peer transactions COMMIT/ROLLBACK.

This IDatabase instance will start off in auto-commit mode when the callback starts. The use of other IDatabase handles from the callback should be avoided unless they are known to be in auto-commit mode. Callbacks that create transactions via begin() or startAtomic() must have matching calls to commit()/endAtomic().

Use this method only for the following purposes:

• (a) Release of cooperative locks on resources
• (b) Cancellation of in-process deferred tasks

The callback takes the following arguments:

• How the current atomic section (if any) or overall transaction (otherwise) ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK)
• This IDatabase instance (since 1.32)

Callbacks will execute in the order they were enqueued.

Note

Use onAtomicSectionCancel() to take action as soon as an atomic section is cancelled

Parameters

callable	$callback
string	$fname	Caller name

Exceptions

DBError

If an error occurs, {

See also

query}

Exceptions

Exception

If the callback runs immediately and an error occurs in it

Since

1.28

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by AtomicSectionUpdate\__construct(), and AutoCommitUpdate\__construct().

pendingWriteCallers()

Wikimedia\Rdbms\IDatabase::pendingWriteCallers

(

)

Get the list of method names that did write queries for this transaction.

Returns

array

Since

1.27

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

pendingWriteQueryDuration()

Wikimedia\Rdbms\IDatabase::pendingWriteQueryDuration

(

$type = self::ESTIMATE_TOTAL

)

Get the time spend running write queries for this transaction.

High values could be due to scanning, updates, locking, and such.

Parameters

string

$type

IDatabase::ESTIMATE_* constant [default: ESTIMATE_ALL]

Returns

float|false Returns false if not transaction is active

Since

1.26

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

ping()

Wikimedia\Rdbms\IDatabase::ping

(

&

$rtt = null

)

Ping the server and try to reconnect if it there is no connection.

Parameters

float | null

&$rtt

Value to store the estimated RTT [optional]

Returns

bool Success or failure

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\TransactionManager\pendingWriteQueryDuration().

primaryPosWait()

Wikimedia\Rdbms\IDatabase::primaryPosWait	(	DBPrimaryPos	$pos,
			$timeout )

Wait for the replica DB to catch up to a given primary DB position.

Note that this does not start any new transactions. If any existing transaction is flushed, and this is called, then queries will reflect the point the DB was synced up to (on success) without interference from REPEATABLE-READ snapshots.

Parameters

DBPrimaryPos	$pos
int	$timeout	The maximum number of seconds to wait for synchronisation

Returns

int|null Zero if the replica DB was past that position already, greater than zero if we waited for some period of time, less than zero if it timed out, and null on error

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.37

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\LoadBalancer\waitForPrimaryPos().

query()

Wikimedia\Rdbms\IDatabase::query	(		$sql,
			$fname = __METHOD__,
			$flags = 0 )

Run an SQL query statement and return the result.

If a connection loss is detected, then an attempt to reconnect will be made. For queries that involve no larger transactions or locks, they will be re-issued for convenience, provided the connection was re-established.

In new code, the query wrappers select(), insert(), update(), delete(), etc. should be used where possible, since they give much better DBMS independence and automatically quote or validate user input in a variety of contexts. This function is generally only useful for queries which are explicitly DBMS-dependent and are unsupported by the query wrappers, such as CREATE TABLE.

However, the query wrappers themselves should call this function.

Parameters

string	$sql	Single-statement SQL query
string	$fname	Caller name; used for profiling/SHOW PROCESSLIST comments
int	$flags	Bit field of IDatabase::QUERY_* constants.

Returns

bool|IResultWrapper True for a successful write query, IResultWrapper object for a successful read query, or false on failure if QUERY_SILENCE_ERRORS is set.

Exceptions

DBQueryError	If the query is issued, fails, and QUERY_SILENCE_ERRORS is not set.
DBExpectedError	If the query is not, and cannot, be issued yet (non-DBQueryError)
DBError	If the query is inherently not allowed (non-DBExpectedError)

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by SqlBagOStuff\createTables(), MySqlLockManager\initConnection(), and MwSql\sqlDoQuery().

queryMulti()

Wikimedia\Rdbms\IDatabase::queryMulti	(	array	$sqls,
		string	$fname = __METHOD__,
		int	$flags = 0,
		?string	$summarySql = null )

Run a batch of SQL query statements and return the results.

See also

IDatabase::query()

Parameters

string[]	$sqls	Map of (statement ID => SQL statement)
string	$fname	Name of the calling function
int	$flags	Bit field of IDatabase::QUERY_* constants
string | null	$summarySql	Virtual SQL for profiling (e.g. "UPSERT INTO TABLE 'x'")

Returns

array<string,QueryStatus> Ordered map of (statement ID => QueryStatus)

Since

1.39

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

replace()

Wikimedia\Rdbms\IDatabase::replace	(		$table,
			$uniqueKeys,
			$rows,
			$fname = __METHOD__ )

Insert row(s) into a table, in the provided order, while deleting conflicting rows.

Conflicts are determined by the provided unique indexes. Note that it is possible for the provided rows to conflict even among themselves; it is preferable for the caller to de-duplicate such input beforehand.

Note some important implications of the deletion semantics:

• If the table has an AUTOINCREMENT column and $rows omit that column, then any conflicting existing rows will be replaced with newer having higher values for that column, even if nothing else changed.
• There might be worse contention than upsert() due to the use of gap-locking. This does not apply to RDBMS types that use predicate locking nor those that just lock the whole table or databases anyway.

Parameters

string	$table	The table name
string | string[] | string[][]	$uniqueKeys	Column name or non-empty list of column name lists that define all applicable unique keys on the table. There must only be one such key. Each unique key on the table is "applicable" unless either: It involves an AUTOINCREMENT column for which no values are assigned in $rows It involves a UUID column for which newly generated UUIDs are assigned in $rows
array | array[]	$rows	Row(s) to insert, in the form of either: A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. Columns belonging to a key in $uniqueKeys must be defined here and non-null. An integer-keyed list of such string-keyed maps, defining a list of new rows. The keys in each map must be identical to each other and in the same order. The rows must not collide with each other.
string	$fname	Calling function name (use METHOD) for logs/profiling

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by WatchedItemStore\duplicateEntry().

restoreFlags()

Wikimedia\Rdbms\IDatabase::restoreFlags

(

$state = self::RESTORE_PRIOR

)

Restore the flags to their prior state before the last setFlag/clearFlag call.

Parameters

string

$state

IDatabase::RESTORE_* constant. [default: RESTORE_PRIOR]

Since

1.28

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

rollback()

Wikimedia\Rdbms\IDatabase::rollback	(		$fname = __METHOD__,
			$flush = self::FLUSHING_ONE )

Rollback a transaction previously started using begin()

Only call this from code with outer transaction scope. See https://www.mediawiki.org/wiki/Database_transactions for details. Nesting of transactions is not supported. If a serious unexpected error occurs, throwing an Exception is preferable, using a pre-installed error handler to trigger rollback (in any case, failure to issue COMMIT will cause rollback server-side).

Query, connection, and onTransaction* callback errors will be suppressed and logged.

Parameters

string	$fname	Calling function name
string	$flush	Flush flag, set to a situationally valid IDatabase::FLUSHING_* constant to disable warnings about explicitly rolling back implicit transactions. This will silently break any ongoing explicit transaction. Only set the flush flag if you are sure that it is safe to ignore these warnings in your context.

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.23 Added $flush parameter

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Maintenance\rollbackTransaction().

select()

Wikimedia\Rdbms\IDatabase::select	(		$table,
			$vars,
			$conds = '',
			$fname = __METHOD__,
			$options = [],
			$join_conds = [] )

Execute a SELECT query constructed using the various parameters provided.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchResultSet instead, which is more readable and less error-prone.

Parameters

string | array

$table

Table name(s)

May be either an array of table names, or a single string holding a table name. If an array is given, table aliases can be specified, for example:

[ 'a' => 'user' ]

This includes the user table in the query, with the alias "a" available for use in field names (e.g. a.user_name).

A derived table, defined by the result of selectSQLText(), requires an alias key and a Subquery instance value which wraps the SQL query, for example:

[ 'c' => new Subquery( 'SELECT ...' ) ]

Joins using parentheses for grouping (since MediaWiki 1.31) may be constructed using nested arrays. For example,

[ 'tableA', 'nestedB' => [ 'tableB', 'b2' => 'tableB2' ] ]

along with $join_conds like

[ 'b2' => [ 'JOIN', 'b_id = b2_id' ], 'nestedB' => [ 'LEFT JOIN', 'b_a = a_id' ] ]

will produce SQL something like

FROM tableA LEFT JOIN (tableB JOIN tableB2 AS b2 ON (b_id = b2_id)) ON (b_a = a_id)

All of the table names given here are automatically run through Database::tableName(), which causes the table prefix (if any) to be added, and various other table name mappings to be performed.

Do not use untrusted user input as a table name. Alias names should not have characters outside of the Basic multilingual plane.

Parameters

string | array

$vars

Field name(s)

May be either a field name or an array of field names. The field names can be complete fragments of SQL, for direct inclusion into the SELECT query. If an array is given, field aliases can be specified, for example:

[ 'maxrev' => 'MAX(rev_id)' ]

This includes an expression with the alias "maxrev" in the query.

If an expression is given, care must be taken to ensure that it is DBMS-independent.

Untrusted user input must not be passed to this parameter.

Parameters

string | array

$conds

May be either a string containing a single condition, or an array of conditions. If an array is given, the conditions constructed from each element are combined with AND.

Array elements may take one of two forms:

• Elements with a numeric key are interpreted as raw SQL fragments.
• Elements with a string key are interpreted as equality conditions, where the key is the field name.
  • If the value of such an array element is a scalar (such as a string), it will be treated as data and thus quoted appropriately. If it is null, an IS NULL clause will be added.
  • If the value is an array, an IN (...) clause will be constructed from its non-null elements, and an IS NULL clause will be added if null is present, such that the field may match any of the elements in the array. The non-null elements will be quoted.

Note that expressions are often DBMS-dependent in their syntax. DBMS-independent wrappers are provided for constructing several types of expression commonly used in condition queries. See:

• IDatabase::buildLike()
• IDatabase::conditional()

Untrusted user input is safe in the values of string keys, however untrusted input must not be used in the array key names or in the values of numeric keys. Escaping of untrusted input used in values of numeric keys should be done via IDatabase::addQuotes()

Use an empty array, string, or IDatabase::ALL_ROWS to select all rows.

You can put simple join conditions here, but this is strongly discouraged. Instead of

// $conds...
'rev_actor = actor_id',

use (see below for $join_conds):

// $join_conds...
'actor' => [ 'JOIN', 'rev_actor = actor_id' ],

Parameters

string	$fname	Caller function name
string | array	$options	Query options

Optional: Array of query options. Boolean options are specified by including them in the array as a string value with a numeric key, for example:

[ 'FOR UPDATE' ]

The supported options are:

• OFFSET: Skip this many rows at the start of the result set. OFFSET with LIMIT can theoretically be used for paging through a result set, but this is discouraged for performance reasons.
• LIMIT: Integer: return at most this many rows. The rows are sorted and then the first rows are taken until the limit is reached. LIMIT is applied to a result set after OFFSET.
• LOCK IN SHARE MODE: Boolean: lock the returned rows so that they can't be changed until the next COMMIT. Cannot be used with aggregate functions (COUNT, MAX, etc., but also DISTINCT).
• FOR UPDATE: Boolean: lock the returned rows so that they can't be changed nor read with LOCK IN SHARE MODE until the next COMMIT. Cannot be used with aggregate functions (COUNT, MAX, etc., but also DISTINCT).
• DISTINCT: Boolean: return only unique result rows.
• GROUP BY: May be either an SQL fragment string naming a field or expression to group by, or an array of such SQL fragments.
• HAVING: May be either an string containing a HAVING clause or an array of conditions building the HAVING clause. If an array is given, the conditions constructed from each element are combined with AND.
• ORDER BY: May be either an SQL fragment giving a field name or expression to order by, or an array of such SQL fragments.
• USE INDEX: This may be either a string giving the index name to use for the query, or an array. If it is an associative array, each key gives the table name (or alias), each value gives the index name to use for that table. All strings are SQL fragments and so should be validated by the caller.
• IGNORE INDEX: This may be either be a string giving an index name to ignore for the query, or an array. If it is an associative array, each key gives the table name (or alias), each value gives the index name to ignore for that table. All strings are SQL fragments and so should be validated by the caller.
• EXPLAIN: In MySQL, this causes an EXPLAIN SELECT query to be run, instead of SELECT.
• MAX_EXECUTION_TIME: (only in MySQL/MariaDB) maximum allowed time to run the query in milliseconds (if database supports it).

And also the following boolean MySQL extensions, see the MySQL manual for documentation:

• STRAIGHT_JOIN
• SQL_BIG_RESULT
• SQL_BUFFER_RESULT
• SQL_SMALL_RESULT
• SQL_CALC_FOUND_ROWS

Parameters

string | array

$join_conds

Join conditions

Optional associative array of table-specific join conditions. Simple conditions can also be specified in the regular $conds, but this is strongly discouraged in favor of the more explicit syntax here.

The key of the array contains the table name or alias. The value is an array with two elements, numbered 0 and 1. The first gives the type of join, the second is the same as the $conds parameter. Thus it can be an SQL fragment, or an array where the string keys are equality and the numeric keys are SQL fragments all AND'd together. For example:

[ 'page' => [ 'LEFT JOIN', 'page_latest=rev_id' ] ]

Returns

IResultWrapper Resulting rows

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by JobQueueDB\doBatchPushInternal(), RefreshImageMetadata\execute(), MediaWiki\ResourceLoader\WikiModule\fetchTitleInfo(), WANCacheReapUpdate\getTitleChangeEvents(), MigrateComments\migrate(), MigrateActors\migrate(), MigrateActors\migrateLogSearch(), MigrateComments\migrateToTemp(), and MediaWiki\Revision\RevisionStore\userWasLastToEdit().

selectDB()

Wikimedia\Rdbms\IDatabase::selectDB

(

$db

)

Change the current database.

This should only be called by a load balancer or if the handle is not attached to one

Parameters

string

$db

Returns

bool True unless an exception was thrown

Exceptions

DBConnectionError	If databasesAreIndependent() is true and connection change fails
DBError	On query error or if database changes are disallowed

Deprecated

Since 1.32 Use selectDomain() instead

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

selectDomain()

Wikimedia\Rdbms\IDatabase::selectDomain

(

$domain

)

Set the current domain (database, schema, and table prefix)

This will throw an error for some database types if the database is unspecified

This should only be called by a load balancer or if the handle is not attached to one

Parameters

string | DatabaseDomain

$domain

Exceptions

DBConnectionError	If databasesAreIndependent() is true and connection change fails
DBError	On query error, if domain changes are disallowed, or the domain is invalid

Since

1.32

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

selectField()

Wikimedia\Rdbms\IDatabase::selectField	(		$table,
			$var,
			$cond = '',
			$fname = __METHOD__,
			$options = [],
			$join_conds = [] )

A SELECT wrapper which returns a single field from a single result row.

If no result rows are returned from the query, false is returned.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchField instead, which is more readable and less error-prone.

Parameters

string | array

$table

Table name. {

See also

select} for details.

Parameters

string | array

$var

The field name to select. This must be a valid SQL fragment: do not use unvalidated user input. Can be an array, but must contain exactly 1 element then. {

See also

select} for details.

Parameters

string | array

$cond

The condition array. {

See also

select} for details.

Parameters

string	$fname	The function name of the caller.
string | array	$options	The query options. {

See also

select} for details.

Parameters

string | array

$join_conds

The query join conditions. {

See also

select} for details.

Returns

mixed|false The value from the field, or false if nothing was found

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by User\addToDatabase(), PopulateArchiveRevId\checkMysqlAutoIncrementBug(), CommentStore\createComment(), MediaWiki\Revision\RevisionStore\getTimestampFromId(), MigrateActors\migrateLogSearch(), and MediaWiki\Revision\RevisionStore\newNullRevision().

selectFieldValues()

Wikimedia\Rdbms\IDatabase::selectFieldValues	(		$table,
			$var,
			$cond = '',
			$fname = __METHOD__,
			$options = [],
			$join_conds = [] )

A SELECT wrapper which returns a list of single field values from result rows.

If no result rows are returned from the query, an empty array is returned.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchFieldValues instead, which is more readable and less error-prone.

Parameters

string | array

$table

Table name. {

See also

select} for details.

Parameters

string	$var	The field name to select. This must be a valid SQL fragment: do not use unvalidated user input.
string | array	$cond	The condition array. {

See also

select} for details.

Parameters

string	$fname	The function name of the caller.
string | array	$options	The query options. {

See also

select} for details.

Parameters

string | array

$join_conds

The query join conditions. {

See also

select} for details.

Returns

array The values from the field in the order they were returned from the DB

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.25

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by PurgeJobUtils\invalidatePages(), MediaWiki\Block\DatabaseBlockStore\purgeExpiredBlocks(), Title\purgeExpiredRestrictions(), and PopulateArchiveRevId\reassignArRevIds().

selectRow()

Wikimedia\Rdbms\IDatabase::selectRow	(		$table,
			$vars,
			$conds,
			$fname = __METHOD__,
			$options = [],
			$join_conds = [] )

Wrapper to IDatabase::select() that only fetches one row (via LIMIT)

If the query returns no rows, false is returned.

This method is convenient for fetching a row based on a unique key condition.

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchRow instead, which is more readable and less error-prone.

Parameters

string | array	$table	Table name
string | array	$vars	Field names
string | array	$conds	Conditions
string	$fname	Caller function name
string | array	$options	Query options
array | string	$join_conds	Join conditions

Returns

stdClass|bool

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by MediaWiki\Revision\RevisionStore\countRevisionsByPageId(), and DatabaseLogEntry\newFromId().

selectRowCount()

Wikimedia\Rdbms\IDatabase::selectRowCount	(		$tables,
			$var = ' *',
			$conds = '',
			$fname = __METHOD__,
			$options = [],
			$join_conds = [] )

Get the number of rows in dataset.

This is useful when trying to do COUNT(*) but with a LIMIT for performance.

Takes the same arguments as IDatabase::select().

New callers should use newSelectQueryBuilder with SelectQueryBuilder::fetchRowCount instead, which is more readable and less error-prone.

Since

1.27 Added $join_conds parameter

Parameters

string | string[]	$tables	Table name(s)
string	$var	Column for which NULL values are not counted [default "*"]
array | string	$conds	Filters on the table
string	$fname	Function name for profiling
array	$options	Options for select
array	$join_conds	Join conditions (since 1.27)

Returns

int Row count

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by PopulateArchiveRevId\isNewInstall().

serverIsReadOnly()

Wikimedia\Rdbms\IDatabase::serverIsReadOnly

(

)

Returns

bool Whether the DB is marked as read-only server-side

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.28

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

setBigSelects()

Wikimedia\Rdbms\IDatabase::setBigSelects

(

$value = true

)

Allow or deny "big selects" for this session only.

This is done by setting the sql_big_selects session variable.

This is a MySQL-specific feature.

Parameters

bool | string

$value

True for allow, false for deny, or "default" to restore the initial value

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, and Wikimedia\Rdbms\DBConnRef.

setFlag()

Wikimedia\Rdbms\IDatabase::setFlag	(		$flag,
			$remember = self::REMEMBER_NOTHING )

Set a flag for this connection.

Parameters

int	$flag	One of (IDatabase::DBO_DEBUG, IDatabase::DBO_TRX)
string	$remember	IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by DatabaseUpdater\__construct().

setLBInfo()

Wikimedia\Rdbms\IDatabase::setLBInfo	(		$nameOrArray,
			$value = null )

Set the entire array or a particular key of the managing load balancer info array.

Keys matching the IDatabase::LB_* constants are also used internally by subclasses

Parameters

array | string	$nameOrArray	The new array or the name of a key to set
array | mixed | null	$value	If $nameOrArray is a string, the new key value (null to unset)

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

setSessionOptions()

Wikimedia\Rdbms\IDatabase::setSessionOptions

(

array

$options

)

Override database's default behavior.

$options include: 'connTimeout' : Set the connection timeout value in seconds. May be useful for very long batch queries such as full-wiki dumps, where a single query reads out over hours or days.

Parameters

array

$options

Returns

void

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, and Wikimedia\Rdbms\DBConnRef.

Referenced by BackupDumper\backupDb().

setTransactionListener()

Wikimedia\Rdbms\IDatabase::setTransactionListener	(		$name,
		callable	$callback = null )

Run a callback after each time any transaction commits or rolls back.

The callback takes two arguments:

• IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK
• This IDatabase object Callbacks must commit any transactions that they begin.

Registering a callback here will not affect writesOrCallbacks() pending.

Since callbacks from this or onTransactionCommitOrIdle() can start and end transactions, a single call to IDatabase::commit might trigger multiple runs of the listener callbacks.

Parameters

string	$name	Callback name
callable | null	$callback	Use null to unset a listener

Since

1.28

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

startAtomic()

Wikimedia\Rdbms\IDatabase::startAtomic	(		$fname = __METHOD__,
			$cancelable = self::ATOMIC_NOT_CANCELABLE )

Begin an atomic section of SQL statements.

Start an implicit transaction if no transaction is already active, set a savepoint (if $cancelable is ATOMIC_CANCELABLE), and track the given section name to enforce that the transaction is not committed prematurely. The end of the section must be signified exactly once, either by endAtomic() or cancelAtomic(). Sections can have have layers of inner sections (sub-sections), but all sections must be ended in order of innermost to outermost. Transactions cannot be started or committed until all atomic sections are closed.

ATOMIC_CANCELABLE is useful when the caller needs to handle specific failure cases by discarding the section's writes. This should not be used for failures when:

• upsert() could easily be used instead
• insert() with IGNORE could easily be used instead
• select() with FOR UPDATE could be checked before issuing writes instead
• The failure is from code that runs after the first write but doesn't need to
• The failures are from contention solvable via onTransactionPreCommitOrIdle()
• The failures are deadlocks; the RDBMs usually discard the whole transaction

Note

callers must use additional measures for situations involving two or more (peer) transactions (e.g. updating two database servers at once). The transaction and savepoint logic of this method only applies to this specific IDatabase instance.

Example usage:

// Start a transaction if there isn't one already
$dbw->startAtomic( __METHOD__ );
// Serialize these thread table updates
$dbw->select( 'thread', '1', [ 'td_id' => $tid ], __METHOD__, 'FOR UPDATE' );
// Add a new comment for the thread
$dbw->insert( 'comment', $row, __METHOD__ );
$cid = $db->insertId();
// Update thread reference to last comment
$dbw->update( 'thread', [ 'td_latest' => $cid ], [ 'td_id' => $tid ], __METHOD__ );
// Demark the end of this conceptual unit of updates
$dbw->endAtomic( __METHOD__ );

Example usage (atomic changes that might have to be discarded):

// Start a transaction if there isn't one already
$sectionId = $dbw->startAtomic( __METHOD__, $dbw::ATOMIC_CANCELABLE );
// Create new record metadata row
$dbw->insert( 'records', $row, __METHOD__ );
// Figure out where to store the data based on the new row's ID
$path = $recordDirectory . '/' . $dbw->insertId();
// Write the record data to the storage system
$status = $fileBackend->create( [ 'dst' => $path, 'content' => $data ] );
if ( $status->isOK() ) {
    // Try to cleanup files orphaned by transaction rollback
    $dbw->onTransactionResolution(
        function ( $type ) use ( $fileBackend, $path ) {
            if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
                $fileBackend->delete( [ 'src' => $path ] );
            }
        },
        __METHOD__
    );
    // Demark the end of this conceptual unit of updates
    $dbw->endAtomic( __METHOD__ );
} else {
    // Discard these writes from the transaction (preserving prior writes)
    $dbw->cancelAtomic( __METHOD__, $sectionId );
}

Since

1.23

Parameters

string	$fname
string	$cancelable	Pass self::ATOMIC_CANCELABLE to use a savepoint and enable self::cancelAtomic() for this section.

Returns

AtomicSectionIdentifier section ID token

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\DBConnRef, and Wikimedia\Rdbms\Database.

Referenced by JobQueueDB\doBatchPushInternal(), LCStoreDB\finishWrite(), and MySqlLockManager\initConnection().

tablePrefix()

Wikimedia\Rdbms\IDatabase::tablePrefix

(

$prefix = null

)

Get/set the table prefix.

Parameters

string | null

$prefix

The table prefix to set, or omitted to leave it unchanged

Returns

string The previous table prefix

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by CloneDatabase\__construct().

trxLevel()

Wikimedia\Rdbms\IDatabase::trxLevel

(

)

Gets the current transaction level.

Historically, transactions were allowed to be "nested". This is no longer supported, so this function really only returns a boolean.

Returns

int The previous value

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

trxTimestamp()

Wikimedia\Rdbms\IDatabase::trxTimestamp

(

)

Get the UNIX timestamp of the time that the transaction was established.

This can be used to reason about the staleness of SELECT data in REPEATABLE-READ transaction isolation level. Callers can assume that if a view-snapshot isolation is used, then the data read by SQL queries is at least up to date to that point (possibly more up-to-date since the first SELECT defines the snapshot).

Returns

float|null Returns null if there is not active transaction

Since

1.25

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

unlock()

Wikimedia\Rdbms\IDatabase::unlock	(		$lockName,
			$method )

Release a lock.

Named locks are not related to transactions

Parameters

string	$lockName	Name of lock to release
string	$method	Name of the calling method

Returns

bool Success

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by SqlBagOStuff\doUnlock().

update()

Wikimedia\Rdbms\IDatabase::update	(		$table,
			$set,
			$conds,
			$fname = __METHOD__,
			$options = [] )

Update all rows in a table that match a given condition.

Parameters

string	$table	Table name
array	$set	Combination map/list where each string-keyed entry maps a column to a literal assigned value and each integer-keyed value is a SQL expression in the format of a column assignment within UPDATE...SET. The (column => value) entries are convenient due to automatic value quoting and conversion of null to NULL. The SQL assignment format is useful for updates like "column = column + X". All assignments have no defined execution order, so they should not depend on each other. Do not modify AUTOINCREMENT or UUID columns in assignments.
array | string	$conds	Condition in the format of IDatabase::select() conditions. In order to prevent possible performance or replication issues or damaging a data accidentally, an empty condition for 'update' queries isn't allowed. IDatabase::ALL_ROWS should be passed explicitly in order to update all rows.
string	$fname	Calling function name (use METHOD) for logs/profiling
string | array	$options	Combination map/list where each string-keyed entry maps a non-boolean option to the option parameters and each integer-keyed value is the name of a boolean option. Supported options are: IGNORE: Boolean: skip update of rows that would cause unique key conflicts. IDatabase::affectedRows() can be used to determine how many rows were updated.

Returns

bool Return true if no exception was thrown (deprecated since 1.33)

Exceptions

DBError

If an error occurs, {

See also

query}

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by SiteStatsUpdate\cacheUpdate(), LocalFileMoveBatch\doDBUpdates(), SiteStatsUpdate\doUpdate(), Title\invalidateCache(), PurgeJobUtils\invalidatePages(), MigrateComments\migrate(), MigrateActors\migrate(), MigrateComments\migrateToTemp(), DeleteLocalPasswords\processUsers(), PopulateArchiveRevId\reassignArRevIds(), and User\saveSettings().

upsert()

Wikimedia\Rdbms\IDatabase::upsert	(		$table,
		array	$rows,
			$uniqueKeys,
		array	$set,
			$fname = __METHOD__ )

Upsert row(s) into a table, in the provided order, while updating conflicting rows.

Conflicts are determined by the provided unique indexes. Note that it is possible for the provided rows to conflict even among themselves; it is preferable for the caller to de-duplicate such input beforehand.

See also

IDatabase::buildExcludedValue()

IDatabase::buildExcludedValue()

Parameters

string	$table	Table name
array | array[]	$rows	Row(s) to insert, in the form of either: A string-keyed map of (column name => value) defining a new row. Values are treated as literals and quoted appropriately; null is interpreted as NULL. Columns belonging to a key in $uniqueKeys must be defined here and non-null. An integer-keyed list of such string-keyed maps, defining a list of new rows. The keys in each map must be identical to each other and in the same order. The rows must not collide with each other.
string | string[] | string[][]	$uniqueKeys	Column name or non-empty list of column name lists that define all applicable unique keys on the table. There must only be one such key. Each unique key on the table is "applicable" unless either: It involves an AUTOINCREMENT column for which no values are assigned in $rows It involves a UUID column for which newly generated UUIDs are assigned in $rows
array	$set	Combination map/list where each string-keyed entry maps a column to a literal assigned value and each integer-keyed value is a SQL assignment expression of the form "<unquoted alphanumeric column> = <SQL expression>". The (column => value) entries are convenient due to automatic value quoting and conversion of null to NULL. The SQL assignment entries are useful for updates like "column = column + X". All of the assignments have no defined execution order, so callers should make sure that they not depend on each other. Do not modify AUTOINCREMENT or UUID columns in assignments, even if they are just "secondary" unique keys. For multi-row upserts, use buildExcludedValue() to reference the value of a column from the corresponding row in $rows that conflicts with the current row.
string	$fname	Calling function name (use METHOD) for logs/profiling

Returns

bool Return true if no exception was thrown (deprecated since 1.33)

Exceptions

DBError

If an error occurs, {

See also

query}

Since

1.22

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by SiteStatsUpdate\doUpdate(), ActorMigrationBase\getInsertValuesWithTempTable(), and QueryPage\recache().

wasConnectionLoss()

Wikimedia\Rdbms\IDatabase::wasConnectionLoss

(

)

Determines if the last query error was due to a dropped connection.

Note that during a connection loss, the prior transaction will have been lost

Returns

bool

Since

1.31

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

wasDeadlock()

Wikimedia\Rdbms\IDatabase::wasDeadlock

(

)

Determines if the last failure was due to a deadlock.

Note that during a deadlock, the prior transaction will have been lost

Returns

bool

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabasePostgres, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

wasErrorReissuable()

Wikimedia\Rdbms\IDatabase::wasErrorReissuable

(

)

Determines if the last query error was due to something outside of the query itself.

Note that the transaction may have been lost, discarding prior writes and results

Returns

bool

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

wasLockTimeout()

Wikimedia\Rdbms\IDatabase::wasLockTimeout

(

)

Determines if the last failure was due to a lock timeout.

Note that during a lock wait timeout, the prior transaction will have been lost

Returns

bool

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabasePostgres, and Wikimedia\Rdbms\DBConnRef.

wasReadOnlyError()

Wikimedia\Rdbms\IDatabase::wasReadOnlyError

(

)

Determines if the last failure was due to the database being read-only.

Returns

bool

Implemented in Wikimedia\Rdbms\Database, Wikimedia\Rdbms\DatabaseMysqlBase, Wikimedia\Rdbms\DatabaseSqlite, and Wikimedia\Rdbms\DBConnRef.

Referenced by LCStoreDB\finishWrite().

writesOrCallbacksPending()

Wikimedia\Rdbms\IDatabase::writesOrCallbacksPending

(

)

Whether there is a transaction open with either possible write queries or unresolved pre-commit/commit/resolution callbacks pending.

This does not count recurring callbacks, e.g. from setTransactionListener().

Returns

bool

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Referenced by Wikimedia\Rdbms\TransactionManager\trxCheckBeforeClose().

writesPending()

Wikimedia\Rdbms\IDatabase::writesPending

(

)

Returns

bool Whether there is a transaction open with possible write queries

Since

1.27

Implemented in Wikimedia\Rdbms\Database, and Wikimedia\Rdbms\DBConnRef.

Member Data Documentation

LOCK_TIMESTAMP

const Wikimedia\Rdbms\IDatabase::LOCK_TIMESTAMP = 1

Flag to return the lock acquisition timestamp (null if not acquired)

Definition at line 105 of file IDatabase.php.

---

The documentation for this interface was generated from the following file:

• includes/libs/rdbms/database/IDatabase.php