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

Inherits Wikimedia\Rdbms\IReadableDatabase.

Inherited by Wikimedia\Rdbms\IDatabaseForOwner, and Wikimedia\Rdbms\IMaintainableDatabase.

Collaboration diagram for Wikimedia\Rdbms\IDatabase:

[legend]

Public Member Functions
	affectedRows ()
	Get the number of rows affected by the last query method call.

	begin ( $fname=__METHOD__, $mode=self::TRANSACTION_EXPLICIT)
	Begin a transaction.

	cancelAtomic ( $fname=__METHOD__, AtomicSectionIdentifier $sectionId=null)
	Cancel an atomic section of SQL statements.

	commit ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
	Commits a transaction previously started using begin()

	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.

	endAtomic ( $fname=__METHOD__)
	Ends an atomic section of SQL statements.

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

	flushSnapshot ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
	Commit any transaction but error out if writes or callbacks are pending.

	getLBInfo ( $name=null)
	Get properties passed down from the server info array of the load balancer.

	getScopedLockAndFlush ( $lockKey, $fname, $timeout)
	Acquire a named lock, flush any transaction, and return an RAII style unlocker object.

	insert ( $table, $rows, $fname=__METHOD__, $options=[])
	Insert row(s) into a table, in the provided order.

	insertId ()
	Get the sequence-based ID assigned by the last query method call.

	insertSelect ( $destTable, $srcTable, $varMap, $conds, $fname=__METHOD__, $insertOptions=[], $selectOptions=[], $selectJoinConds=[])
	INSERT SELECT wrapper.

	isReadOnly ()
	Check if this DB server is marked as read-only according to load balancer info.

	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)

	newDeleteQueryBuilder ()
	Get an DeleteQueryBuilder bound to this connection.

	newInsertQueryBuilder ()
	Get an InsertQueryBuilder bound to this connection.

	newReplaceQueryBuilder ()
	Get an ReplaceQueryBuilder bound to this connection.

	newUpdateQueryBuilder ()
	Get an UpdateQueryBuilder bound to this connection.

	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.

	query ( $sql, $fname=__METHOD__, $flags=0)
	Run an SQL query statement and return the result.

	replace ( $table, $uniqueKeys, $rows, $fname=__METHOD__)
	Insert row(s) into a table, in the provided order, while deleting conflicting rows.

	rollback ( $fname=__METHOD__, $flush=self::FLUSHING_ONE)
	Rollback a transaction previously started using begin()

	setSessionOptions (array $options)
	Override database's default behavior.

	startAtomic ( $fname=__METHOD__, $cancelable=self::ATOMIC_NOT_CANCELABLE)
	Begin an atomic section of SQL statements.

	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.

Public Member Functions inherited from Wikimedia\Rdbms\IReadableDatabase
	__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.

	andExpr (array $conds)
	See Expression::__construct()

	close ( $fname=__METHOD__)
	Close the database connection.

	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.

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

	estimateRowCount ( $tables, $var=' *', $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Estimate the number of rows in dataset.

	expr (string $field, string $op, $value)
	See Expression::__construct()

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

	getDomainID ()
	Return the currently selected domain ID.

	getLag ()
	Get the seconds of replication lag on this database server.

	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.

	getSessionLagStatus ()
	Get a cached estimate of the seconds of replication lag on this database server, using the estimate obtained at the start of the current transaction if one is active.

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

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

	isOpen ()

	lastErrno ()
	Get the RDBMS-specific error code from the last attempted query statement.

	lastError ()
	Get the RDBMS-specific error description from the last attempted query statement.

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

	newUnionQueryBuilder ()
	Create an empty UnionQueryBuilder which can be used to run queries against this connection.

	orExpr (array $conds)
	See Expression::__construct()

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

	select ( $tables, $vars, $conds='', $fname=__METHOD__, $options=[], $join_conds=[])
	Execute a SELECT query constructed using the various parameters provided.

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

	selectField ( $tables, $var, $cond='', $fname=__METHOD__, $options=[], $join_conds=[])
	A SELECT wrapper which returns a single field from a single result row.

	selectFieldValues ( $tables, $var, $cond='', $fname=__METHOD__, $options=[], $join_conds=[])
	A SELECT wrapper which returns a list of single field values from result rows.

	selectRow ( $tables, $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.

	tablePrefix ( $prefix=null)
	Get/set the table prefix.

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)

	buildComparison (string $op, array $conds)
	Build a condition comparing multiple values, for use with indexes that cover multiple fields, common when e.g.

	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, $tables, $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 ( $tables, $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 "OR" condition with pairs from a two-dimensional array.

	selectSQLText ( $tables, $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 (string $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.

	unionQueries ( $sqls, $all, $options=[])
	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 Member Functions inherited from Wikimedia\Rdbms\Database\IDatabaseFlags
	clearFlag ( $flag, $remember=self::REMEMBER_NOTHING)
	Clear a flag for this connection.

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

	restoreFlags ( $state=self::RESTORE_PRIOR)
	Restore the flags to their prior state before the last setFlag/clearFlag call.

	setFlag ( $flag, $remember=self::REMEMBER_NOTHING)
	Set a flag for this connection.

Public Attributes
const	ATOMIC_CANCELABLE = 'cancelable'
	Atomic section is cancelable.

const	ATOMIC_NOT_CANCELABLE = ''
	Atomic section is not cancelable.

const	ESTIMATE_DB_APPLY = 'apply'
	Estimate time to apply (scanning, applying)

const	ESTIMATE_TOTAL = 'total'
	Estimate total time (RTT, scanning, waiting on locks, applying)

const	FLUSHING_ALL_PEERS = 'flush'
	Commit/rollback is from the connection manager for the IDatabase handle.

const	FLUSHING_INTERNAL = 'flush-internal'
	Commit/rollback is from the IDatabase handle internally.

const	FLUSHING_ONE = ''
	Commit/rollback is from outside the IDatabase handle and connection manager.

const	LB_READ_ONLY_REASON = 'readOnlyReason'
	Field for getLBInfo()/setLBInfo()

const	LB_TRX_ROUND_ID = 'trxRoundId'
	Field for getLBInfo()/setLBInfo()

const	LOCK_TIMESTAMP = 1
	Flag to return the lock acquisition timestamp (null if not acquired)

const	ROLE_STATIC_CLONE = 'static-clone'
	Replica server within a static dataset.

const	ROLE_STREAMING_MASTER = 'streaming-master'
	Primary server than can stream writes to replica servers.

const	ROLE_STREAMING_REPLICA = 'streaming-replica'
	Replica server that receives writes from a primary server.

const	ROLE_UNKNOWN = 'unknown'
	Server with unknown topology role.

const	TRANSACTION_EXPLICIT = ''
	Transaction is requested by regular caller outside of the DB layer.

const	TRANSACTION_INTERNAL = 'implicit'
	Transaction is requested internally via DBO_TRX/startAtomic()

const	TRIGGER_CANCEL = 4
	Callback triggered by atomic section cancel (ROLLBACK TO SAVEPOINT)

const	TRIGGER_COMMIT = 2
	Callback triggered by COMMIT.

const	TRIGGER_IDLE = 1
	Callback triggered immediately due to no active transaction.

const	TRIGGER_ROLLBACK = 3
	Callback triggered by ROLLBACK.

Public Attributes inherited from Wikimedia\Rdbms\IReadableDatabase
const	UNION_ALL = true
	Parameter to unionQueries() for UNION ALL.

const	UNION_DISTINCT = false
	Parameter to unionQueries() for UNION DISTINCT.

Public Attributes inherited from Wikimedia\Rdbms\Platform\ISQLPlatform
const	ALL_ROWS = '*'
	Unconditional update/delete of whole table.

const	CALLER_SUBQUERY = 'subquery'
	Special value for ->caller() / $fname parameter used when providing a caller is not expected, because we're formatting a subquery that won't be executed directly.

const	CALLER_UNKNOWN = 'unknown'
	Special value for ->caller() / $fname parameter used when a caller is not provided.

const	LIST_AND = 1
	Combine list with AND clauses.

const	LIST_COMMA = 0
	Combine list with comma delimiters.

const	LIST_NAMES = 3
	Treat as field name and do not apply value escaping.

const	LIST_OR = 4
	Combine list with OR clauses.

const	LIST_SET = 2
	Convert map into a SET clause.

const	QUERY_CHANGE_LOCKS = 512
	Query is a command for advisory locks.

const	QUERY_CHANGE_NONE = 32
	Query is a read-only Data Query Language query.

const	QUERY_CHANGE_ROWS = 128
	Query is a Data Manipulation Language command (INSERT, DELETE, LOCK, ...)

const	QUERY_CHANGE_SCHEMA = 256
	Query is a Data Definition Language command.

const	QUERY_CHANGE_TRX = 64
	Query is a Transaction Control Language command (BEGIN, USE, SET, ...)

const	QUERY_IGNORE_DBO_TRX = 8
	Ignore the current presence of any DBO_TRX flag.

const	QUERY_NO_RETRY = 16
	Do not try to retry the query if the connection was lost.

const	QUERY_NORMAL = 0
	Idiom for "no special flags".

const	QUERY_PSEUDO_PERMANENT = 2
	Track a TEMPORARY table CREATE as if it was for a permanent table (for testing)

const	QUERY_REPLICA_ROLE = 4
	Enforce that a query does not make effective writes.

const	QUERY_SILENCE_ERRORS = 1
	Ignore query errors and return false when they happen.

Public Attributes inherited from Wikimedia\Rdbms\Database\IDatabaseFlags
const	DBO_COMPRESS = 512
	Enable compression in connection protocol.

const	DBO_DDLMODE = 128
	Schema file mode; was used by Oracle.

const	DBO_DEBUG = 1
	Enable debug logging of all SQL queries.

const	DBO_DEFAULT = 16
	Join load balancer transaction rounds (which control DBO_TRX) in non-CLI mode.

const	DBO_GAUGE = 1024
	Optimize connection for guaging server state (e.g.

const	DBO_IGNORE = 4
	Unused since 1.31.

const	DBO_NOBUFFER = 2
	Unused since 1.34.

const	DBO_PERSISTENT = 32
	Use DB persistent connections if possible.

const	DBO_SSL = 256
	Enable SSL/TLS in connection protocol.

const	DBO_SYSDBA = 64
	DBA session mode; was used by Oracle.

const	DBO_TRX = 8
	Automatically start a transaction before running a query if none is active.

const	REMEMBER_NOTHING = ''
	Do not remember the prior flags.

const	REMEMBER_PRIOR = 'remember'
	Remember the prior flags.

const	RESTORE_INITIAL = 'initial'
	Restore to the initial flag state.

const	RESTORE_PRIOR = 'prior'
	Restore to the prior flag state.

Detailed Description

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

Definition at line 39 of file IDatabase.php.

Member Function Documentation

◆ affectedRows()

Wikimedia\Rdbms\IDatabase::affectedRows ( )

Get the number of rows affected by the last query method call.

This method should only be called when all the following hold true:

(a) A method call was made to insert(), upsert(), replace(), update(), delete(), insertSelect(), query() with a non-SELECT statement, or queryMulti() with a non-SELECT terminal statement
(b) The method call succeeded
(c) No subsequent method calls were made, with the exception of affectedRows(), lastErrno(), lastError(), and getType()

In all other cases, the return value is unspecified.

UPDATE queries consider rows affected even when all their new column values match the previous values. Such rows can be excluded from the count by changing the WHERE clause to filter them out.

If the last query method call was to query() or queryMulti(), then the results are based on the (last) statement provided to that call and are driver-specific.

Returns: int

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

Referenced by MediaWiki\User\User\addToDatabase(), DeleteLocalPasswords\processUsers(), and MediaWiki\User\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 an optimization to save rountrips, 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.

◆ 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 Wikimedia\Rdbms\LoadBalancer\commitPrimaryChanges(), and Maintenance\commitTransaction().

◆ delete()

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

Delete all rows in a table that match a condition.

This operation will be seen by affectedRows()/insertId() as one query statement, regardless of how many statements are actually sent by the class implementation.

Access: internal: callers outside of rdbms library should use DeleteQueryBuilder instead.

Parameters

string	$table	Unqualified name of table
	string\|IExpression\|array<string,?scalar\|non-empty-array<int,?scalar>\|RawSQLValue>\|array<int,string\|IExpression>	$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.

◆ 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.

This operation will be seen by affectedRows()/insertId() as one query statement, regardless of how many statements are actually sent by the class implementation.

Parameters

string	$delTable	Unqualified name of table to delete rows from.
string	$joinTable	Unqualified name of reference table to join on.
string	$delVar	The variable to join on, in the first table.
string	$joinVar	The variable to join on, in the second table.
	string\|IExpression\|array<string,?scalar\|non-empty-array<int,?scalar>\|RawSQLValue>\|array<int,string\|IExpression>	$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 write queries
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 MediaWiki\Revision\RevisionStore\insertRevisionOn().

◆ 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().

◆ 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.

◆ 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 server after waiting on replication to catch up to the primary server.

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.

◆ getLBInfo()

Wikimedia\Rdbms\IDatabase::getLBInfo ( $name = null )

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

Access: internal: should not be called outside of rdbms library.

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\waitForPrimaryPos().

◆ 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 server 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().

◆ insert()

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

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

This operation will be seen by affectedRows()/insertId() as one query statement, regardless of how many statements are actually sent by the class implementation.

Access: internal: callers outside of rdbms library should use InsertQueryBuilder instead.

Parameters

string	$table	Unqualified name of table
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.

◆ insertId()

Wikimedia\Rdbms\IDatabase::insertId ( )

Get the sequence-based ID assigned by the last query method call.

This method should only be called when all the following hold true:

(a) A method call was made to insert(), upsert(), replace(), or insertSelect()
(b) The method call attempts to insert exactly one row
(c) The method call omits the value of exactly one auto-increment column
(d) The method call succeeded
(e) No subsequent method calls were made, with the exception of affectedRows(), lastErrno(), lastError(), and getType()

In all other cases, the return value is unspecified.

When the query method is either insert() with "IGNORE", upsert(), or insertSelect(), callers should first check affectedRows() before calling this method, making sure that the query method actually created a row. Otherwise, an ID from a previous insert might be incorrectly assumed to belong to last insert.

Returns: int

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

Referenced by MediaWiki\User\User\addToDatabase(), and MediaWiki\CommentStore\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.

This operation will be seen by affectedRows()/insertId() as one query statement, regardless of how many statements are actually sent by the class implementation.

Parameters

string	$destTable	Unqualified name of destination table
string \| array	$srcTable	Unqualified name of source table(s) (use an array for 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()
	string\|IExpression\|array<string,?scalar\|non-empty-array<int,?scalar>\|RawSQLValue>\|array<int,string\|IExpression>	$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.

◆ isReadOnly()

Wikimedia\Rdbms\IDatabase::isReadOnly ( )

Check if this DB server is marked as read-only according to load balancer info.

Note: LoadBalancer checks serverIsReadOnly() when setting the load balancer info array

Returns: bool

Since: 1.27

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

Referenced by LCStoreDB\finishWrite(), and LCStoreDB\startWrite().

◆ 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\deleteObjectsExpiringBefore(), and 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	Unqualified name of table(s) (use an array for a join)
	string\|IExpression\|array<string,?scalar\|non-empty-array<int,?scalar>\|RawSQLValue>\|array<int,string\|IExpression>	$conds Condition in the format of IDatabase::select() conditions
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

Deprecated: since 1.43; Use SelectQueryBuilder::acquireRowLocks

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

◆ 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.

◆ newDeleteQueryBuilder()

Wikimedia\Rdbms\IDatabase::newDeleteQueryBuilder ( )

Get an DeleteQueryBuilder bound to this connection.

This is overridden by DBConnRef.

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: DeleteQueryBuilder

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

Referenced by SqlBagOStuff\deleteAll(), MediaWiki\Deferred\LinksUpdate\LinksTable\doWrites(), LCStoreDB\finishWrite(), MediaWiki\Title\Title\purgeExpiredRestrictions(), and MediaWiki\SpecialPage\QueryPage\recache().

◆ newInsertQueryBuilder()

Wikimedia\Rdbms\IDatabase::newInsertQueryBuilder ( )

Get an InsertQueryBuilder bound to this connection.

This is overridden by DBConnRef.

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: InsertQueryBuilder

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

Referenced by MediaWiki\User\User\addToDatabase(), MediaWiki\CommentStore\CommentStore\createComment(), JobQueueDB\doBatchPushInternal(), MediaWiki\Deferred\SiteStatsUpdate\doUpdate(), MediaWiki\Deferred\LinksUpdate\LinksTable\doWrites(), LCStoreDB\finishWrite(), and MediaWiki\SpecialPage\QueryPage\recache().

◆ newReplaceQueryBuilder()

Wikimedia\Rdbms\IDatabase::newReplaceQueryBuilder ( )

Get an ReplaceQueryBuilder bound to this connection.

This is overridden by DBConnRef.

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: ReplaceQueryBuilder

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

◆ newUpdateQueryBuilder()

Wikimedia\Rdbms\IDatabase::newUpdateQueryBuilder ( )

Get an UpdateQueryBuilder bound to this connection.

This is overridden by DBConnRef.

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: UpdateQueryBuilder

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

Referenced by MediaWiki\Deferred\SiteStatsUpdate\cacheUpdate(), LocalFileMoveBatch\doDBUpdates(), MediaWiki\Deferred\SiteStatsUpdate\doUpdate(), MediaWiki\Title\Title\invalidateCache(), PurgeJobUtils\invalidatePages(), DeleteLocalPasswords\processUsers(), and MediaWiki\User\User\saveSettings().

◆ 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 MediaWiki\Deferred\AtomicSectionUpdate\__construct(), and MediaWiki\Deferred\AutoCommitUpdate\__construct().

◆ 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.

Callers should avoid the use of statements like BEGIN, COMMIT, and ROLLBACK. Methods like startAtomic(), endAtomic(), and cancelAtomic() can be used instead.

Parameters

string \| Query	$sql	Single-statement SQL query
string	$fname	Caller name; used for profiling/SHOW PROCESSLIST comments
int	$flags	Bit field of ISQLPlatform::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(), Wikimedia\Rdbms\Replication\MysqlReplicationReporter\fetchSecondsSinceHeartbeat(), Wikimedia\Rdbms\Replication\MysqlReplicationReporter\getLagFromSlaveStatus(), Wikimedia\Rdbms\Replication\MysqlReplicationReporter\getServerGTIDs(), Wikimedia\Rdbms\Replication\MysqlReplicationReporter\getServerId(), Wikimedia\Rdbms\Replication\MysqlReplicationReporter\getServerRoleStatus(), Wikimedia\Rdbms\Replication\MysqlReplicationReporter\getServerUUID(), Wikimedia\Rdbms\Replication\MysqlReplicationReporter\primaryPosWait(), and MwSql\sqlDoQuery().

◆ 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.

This operation will be seen by affectedRows()/insertId() as one query statement, regardless of how many statements are actually sent by the class implementation.

Access: internal: callers outside of rdbms library should use ReplaceQueryBuilder instead.

Parameters

string	$table	Unqualified name of table
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, Wikimedia\Rdbms\DatabaseMySQL, Wikimedia\Rdbms\DatabaseSqlite, 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 Wikimedia\Rdbms\LoadBalancer\rollbackPrimaryChanges(), and Maintenance\rollbackTransaction().

◆ setSessionOptions()

Wikimedia\Rdbms\IDatabase::setSessionOptions ( array $options )

Override database's default behavior.

Not all options are supported on all database backends; unsupported options are silently ignored.

$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. Only supported on MySQL and MariaDB.
'groupConcatMaxLen': Maximum length of a GROUP_CONCAT() result. Only supported on MySQL and MariaDB.

Parameters

array $options

Returns: void

Exceptions

DBError If an error occurs, {

See also: query}

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

Referenced by BackupDumper\backupDb().

◆ 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(), and LCStoreDB\finishWrite().

◆ 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.

Referenced by Wikimedia\Rdbms\Replication\ReplicationReporter\getRecordedTransactionLagStatus().

◆ 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\deleteObjectsExpiringBefore(), and SqlBagOStuff\doUnlock().

◆ update()

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

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

This operation will be seen by affectedRows()/insertId() as one query statement, regardless of how many statements are actually sent by the class implementation.

Access: internal: callers outside of rdbms library should use UpdateQueryBuilder instead.

Parameters

string	$table	Unqualified name of table
	array<string,?scalar\|RawSQLValue>\|array<int,string>	$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.
	string\|IExpression\|array<string,?scalar\|non-empty-array<int,?scalar>\|RawSQLValue>\|array<int,string\|IExpression>	$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() includes all matching rows, that includes also rows not updated due to key conflict.

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.

◆ 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.

This operation will be seen by affectedRows()/insertId() as one query statement, regardless of how many statements are actually sent by the class implementation.

Access: internal: callers outside of rdbms library should use InsertQueryBuilder instead.

Parameters

string	$table	Unqualified name of table
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<string,?scalar\|RawSQLValue>\|array<int,string>	$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

Exceptions

DBError If an error occurs, {

See also: query}

Since: 1.22

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

Member Data Documentation

◆ ATOMIC_CANCELABLE

const Wikimedia\Rdbms\IDatabase::ATOMIC_CANCELABLE = 'cancelable'

Atomic section is cancelable.

Definition at line 57 of file IDatabase.php.

◆ ATOMIC_NOT_CANCELABLE

const Wikimedia\Rdbms\IDatabase::ATOMIC_NOT_CANCELABLE = ''

Atomic section is not cancelable.

Definition at line 55 of file IDatabase.php.

◆ ESTIMATE_DB_APPLY

const Wikimedia\Rdbms\IDatabase::ESTIMATE_DB_APPLY = 'apply'

Estimate time to apply (scanning, applying)

Definition at line 69 of file IDatabase.php.

◆ ESTIMATE_TOTAL

const Wikimedia\Rdbms\IDatabase::ESTIMATE_TOTAL = 'total'

Estimate total time (RTT, scanning, waiting on locks, applying)

Definition at line 67 of file IDatabase.php.

◆ FLUSHING_ALL_PEERS

const Wikimedia\Rdbms\IDatabase::FLUSHING_ALL_PEERS = 'flush'

Commit/rollback is from the connection manager for the IDatabase handle.

Definition at line 62 of file IDatabase.php.

◆ FLUSHING_INTERNAL

const Wikimedia\Rdbms\IDatabase::FLUSHING_INTERNAL = 'flush-internal'

Commit/rollback is from the IDatabase handle internally.

Definition at line 64 of file IDatabase.php.

◆ FLUSHING_ONE

const Wikimedia\Rdbms\IDatabase::FLUSHING_ONE = ''

Commit/rollback is from outside the IDatabase handle and connection manager.

Definition at line 60 of file IDatabase.php.

◆ LB_READ_ONLY_REASON

const Wikimedia\Rdbms\IDatabase::LB_READ_ONLY_REASON = 'readOnlyReason'

Field for getLBInfo()/setLBInfo()

Definition at line 77 of file IDatabase.php.

◆ LB_TRX_ROUND_ID

const Wikimedia\Rdbms\IDatabase::LB_TRX_ROUND_ID = 'trxRoundId'

Field for getLBInfo()/setLBInfo()

Definition at line 75 of file IDatabase.php.

◆ LOCK_TIMESTAMP

const Wikimedia\Rdbms\IDatabase::LOCK_TIMESTAMP = 1

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

Definition at line 72 of file IDatabase.php.

◆ ROLE_STATIC_CLONE

const Wikimedia\Rdbms\IDatabase::ROLE_STATIC_CLONE = 'static-clone'

Replica server within a static dataset.

Definition at line 84 of file IDatabase.php.

Referenced by Wikimedia\Rdbms\Replication\ReplicationReporter\getLag(), Wikimedia\Rdbms\Replication\ReplicationReporter\getTopologyBasedReadOnlyReason(), and Wikimedia\Rdbms\Replication\MysqlReplicationReporter\primaryPosWait().

◆ ROLE_STREAMING_MASTER

const Wikimedia\Rdbms\IDatabase::ROLE_STREAMING_MASTER = 'streaming-master'

Primary server than can stream writes to replica servers.

Definition at line 80 of file IDatabase.php.

Referenced by Wikimedia\Rdbms\Replication\ReplicationReporter\getLag().

◆ ROLE_STREAMING_REPLICA

const Wikimedia\Rdbms\IDatabase::ROLE_STREAMING_REPLICA = 'streaming-replica'

Replica server that receives writes from a primary server.

Definition at line 82 of file IDatabase.php.

Referenced by Wikimedia\Rdbms\Replication\ReplicationReporter\getApproximateLagStatus(), and Wikimedia\Rdbms\Replication\ReplicationReporter\getTopologyBasedReadOnlyReason().

◆ ROLE_UNKNOWN

const Wikimedia\Rdbms\IDatabase::ROLE_UNKNOWN = 'unknown'

Server with unknown topology role.

Definition at line 86 of file IDatabase.php.

◆ TRANSACTION_EXPLICIT

const Wikimedia\Rdbms\IDatabase::TRANSACTION_EXPLICIT = ''

Transaction is requested by regular caller outside of the DB layer.

Definition at line 50 of file IDatabase.php.

◆ TRANSACTION_INTERNAL

const Wikimedia\Rdbms\IDatabase::TRANSACTION_INTERNAL = 'implicit'

Transaction is requested internally via DBO_TRX/startAtomic()

Definition at line 52 of file IDatabase.php.

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

◆ TRIGGER_CANCEL

const Wikimedia\Rdbms\IDatabase::TRIGGER_CANCEL = 4

Callback triggered by atomic section cancel (ROLLBACK TO SAVEPOINT)

Definition at line 47 of file IDatabase.php.

◆ TRIGGER_COMMIT

const Wikimedia\Rdbms\IDatabase::TRIGGER_COMMIT = 2

Callback triggered by COMMIT.

Definition at line 43 of file IDatabase.php.

◆ TRIGGER_IDLE

const Wikimedia\Rdbms\IDatabase::TRIGGER_IDLE = 1

Callback triggered immediately due to no active transaction.

Definition at line 41 of file IDatabase.php.

◆ TRIGGER_ROLLBACK

const Wikimedia\Rdbms\IDatabase::TRIGGER_ROLLBACK = 3

Callback triggered by ROLLBACK.

Definition at line 45 of file IDatabase.php.

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

includes/libs/rdbms/database/IDatabase.php

Public Member Functions

Public Attributes

Detailed Description

Member Function Documentation

◆ affectedRows()

◆ begin()

◆ cancelAtomic()

◆ commit()

◆ delete()

◆ deleteJoin()

◆ doAtomicSection()

◆ endAtomic()

◆ explicitTrxActive()

◆ flushSnapshot()

◆ getLBInfo()

◆ getScopedLockAndFlush()

◆ insert()

◆ insertId()

◆ insertSelect()

◆ isReadOnly()

◆ lock()

◆ lockForUpdate()

◆ lockIsFree()

◆ newDeleteQueryBuilder()

◆ newInsertQueryBuilder()

◆ newReplaceQueryBuilder()

◆ newUpdateQueryBuilder()

◆ onAtomicSectionCancel()

◆ onTransactionCommitOrIdle()

◆ onTransactionPreCommitOrIdle()

◆ onTransactionResolution()

◆ query()

◆ replace()

◆ rollback()

◆ setSessionOptions()

◆ startAtomic()

◆ trxLevel()

◆ trxTimestamp()

◆ unlock()

◆ update()

◆ upsert()

Member Data Documentation

◆ ATOMIC_CANCELABLE

◆ ATOMIC_NOT_CANCELABLE

◆ ESTIMATE_DB_APPLY

◆ ESTIMATE_TOTAL

◆ FLUSHING_ALL_PEERS

◆ FLUSHING_INTERNAL

◆ FLUSHING_ONE

◆ LB_READ_ONLY_REASON

◆ LB_TRX_ROUND_ID

◆ LOCK_TIMESTAMP

◆ ROLE_STATIC_CLONE

◆ ROLE_STREAMING_MASTER

◆ ROLE_STREAMING_REPLICA

◆ ROLE_UNKNOWN

◆ TRANSACTION_EXPLICIT

◆ TRANSACTION_INTERNAL

◆ TRIGGER_CANCEL

◆ TRIGGER_COMMIT

◆ TRIGGER_IDLE

◆ TRIGGER_ROLLBACK