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Wikimedia\Rdbms\LBFactoryMulti Class Reference

A multi-database, multi-master factory for Wikimedia and similar installations. More...

Inheritance diagram for Wikimedia\Rdbms\LBFactoryMulti:
Collaboration diagram for Wikimedia\Rdbms\LBFactoryMulti:

Public Member Functions

 __construct (array $conf)
 Template override precedence (highest => lowest): More...
 
 forEachLB ( $callback, array $params=[])
 Execute a function for each currently tracked (instantiated) load balancer. More...
 
 getAllExternalLBs ()
 Get cached (tracked) load balancers for all external database clusters. More...
 
 getAllMainLBs ()
 Get cached (tracked) load balancers for all main database clusters. More...
 
 getExternalLB ( $cluster)
 Get a cached (tracked) load balancer for external storage. More...
 
 getMainLB ( $domain=false)
 Get a cached (tracked) load balancer object. More...
 
 newExternalLB ( $cluster, $owner=null)
 Create a new load balancer for external storage. More...
 
 newMainLB ( $domain=false, $owner=null)
 Create a new load balancer object. More...
 
- Public Member Functions inherited from Wikimedia\Rdbms\LBFactory
 __construct (array $conf)
 Construct a manager of ILoadBalancer objects. More...
 
 __destruct ()
 
 appendShutdownCPIndexAsQuery ( $url, $index)
 Append ?cpPosIndex parameter to a URL for ChronologyProtector purposes if needed. More...
 
 beginMasterChanges ( $fname=__METHOD__)
 Flush any master transaction snapshots and set DBO_TRX (if DBO_DEFAULT is set) More...
 
 closeAll ()
 Close all open database connections on all open load balancers. More...
 
 commitAll ( $fname=__METHOD__, array $options=[])
 Commit open transactions on all connections. More...
 
 commitAndWaitForReplication ( $fname, $ticket, array $opts=[])
 Convenience method for safely running commitMasterChanges()/waitForReplication() More...
 
 commitMasterChanges ( $fname=__METHOD__, array $options=[])
 Commit changes and clear view snapshots on all master connections. More...
 
 destroy ()
 Disables all load balancers. More...
 
 disableChronologyProtection ()
 Disable the ChronologyProtector for all load balancers. More...
 
 flushReplicaSnapshots ( $fname=__METHOD__)
 Commit all replica DB transactions so as to flush any REPEATABLE-READ or SSI snapshot. More...
 
 getChronologyProtectorClientId ()
 Get the client ID of the ChronologyProtector instance. More...
 
 getChronologyProtectorTouched ( $dbName)
 
 getEmptyTransactionTicket ( $fname)
 Get a token asserting that no transaction writes are active. More...
 
 getLocalDomainID ()
 Get the local (and default) database domain ID of connection handles. More...
 
 hasMasterChanges ()
 Determine if any master connection has pending changes. More...
 
 hasOrMadeRecentMasterChanges ( $age=null)
 Determine if any master connection has pending/written changes from this request. More...
 
 hasTransactionRound ()
 Check if an explicit transaction round is active. More...
 
 isReadyForRoundOperations ()
 Check if transaction rounds can be started, committed, or rolled back right now. More...
 
 laggedReplicaUsed ()
 Detemine if any lagged replica DB connection was used. More...
 
 redefineLocalDomain ( $domain)
 Close all connection and redefine the local domain for testing or schema creation. More...
 
 resolveDomainID ( $domain)
 
 rollbackMasterChanges ( $fname=__METHOD__)
 Rollback changes on all master connections. More...
 
 setAgentName ( $agent)
 
 setIndexAliases (array $aliases)
 Convert certain index names to alternative names before querying the DB. More...
 
 setLocalDomainPrefix ( $prefix)
 Set a new table prefix for the existing local domain ID for testing. More...
 
 setRequestInfo (array $info)
 
 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. More...
 
 setWaitForReplicationListener ( $name, callable $callback=null)
 Add a callback to be run in every call to waitForReplication() before waiting. More...
 
 shutdown ( $mode=self::SHUTDOWN_CHRONPROT_SYNC, callable $workCallback=null, &$cpIndex=null, &$cpClientId=null)
 Prepare all currently tracked (instantiated) load balancers for shutdown. More...
 
 waitForReplication (array $opts=[])
 Waits for the replica DBs to catch up to the current master position. More...
 

Private Member Functions

 getDomainDatabase ( $domain=false)
 
 getSectionForDomain ( $domain=false)
 
 makeServerArray (array $serverTemplate, array $groupLoads)
 Make a server array as expected by LoadBalancer::__construct() More...
 
 newLoadBalancer ( $serverTemplate, $groupLoads, $readOnlyReason, $owner)
 Make a new load balancer object based on template and load array. More...
 
 reindexGroupLoads (array $groupLoads)
 Take a group load array indexed by group then server, and reindex it by server then group. More...
 

Private Attributes

LoadBalancer [] $externalLBs = []
 
int [][] $externalLoads = []
 Map of (cluster => host => load ratio) More...
 
array $externalTemplateOverrides = []
 Server config map overriding "serverTemplate" for external storage. More...
 
int [][][] $groupLoadsByDB = []
 Map of (database => group => host => load ratio) More...
 
int [][][] $groupLoadsBySection = []
 Map of (section => group => host => load ratio) More...
 
string [] $hostsByName = []
 Map of (hostname => IP address) More...
 
string $lastDomain
 
string $lastSection
 
string $loadMonitorClass
 An ILoadMonitor class. More...
 
LoadBalancer [] $mainLBs = []
 
array $masterTemplateOverrides = []
 Server config override map for all main and external master servers. More...
 
string [] bool [] $readOnlyBySection = []
 A map of section name to read-only message. More...
 
string [] $sectionsByDB = []
 Map of (database name => section name) More...
 
array $serverTemplate = []
 Server config map ("host", "hostName", "load", and "groupLoads" are ignored) More...
 
array [] $templateOverridesByCluster = []
 Map of (cluster => server config map overrides) for external storage. More...
 
array [] $templateOverridesBySection = []
 Map of (section => server config map overrides) More...
 
array [] $templateOverridesByServer = []
 Map of (host => server config map overrides) for main and external servers. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from Wikimedia\Rdbms\LBFactory
static getCPInfoFromCookieValue ( $value, $minTimestamp)
 
static makeCookieValueFromCPIndex ( $index, $time, $clientId)
 
- Public Attributes inherited from Wikimedia\Rdbms\LBFactory
const ROUND_BEGINNING = 'within-begin'
 
const ROUND_COMMIT_CALLBACKS = 'within-commit-callbacks'
 
const ROUND_COMMITTING = 'within-commit'
 
const ROUND_CURSORY = 'cursory'
 
const ROUND_ROLLBACK_CALLBACKS = 'within-rollback-callbacks'
 
const ROUND_ROLLING_BACK = 'within-rollback'
 
- Protected Member Functions inherited from Wikimedia\Rdbms\LBFactory
 baseLoadBalancerParams ( $owner)
 Get parameters to ILoadBalancer::__construct() More...
 
 forEachLBCallMethod ( $methodName, array $args=[])
 Call a method of each tracked load balancer. More...
 
 getChronologyProtector ()
 
 getOwnershipId ()
 
 initLoadBalancer (ILoadBalancer $lb)
 
 shutdownChronologyProtector (ChronologyProtector $cp, $workCallback, $mode, &$cpIndex=null)
 Get and record all of the staged DB positions into persistent memory storage. More...
 
- Protected Attributes inherited from Wikimedia\Rdbms\LBFactory
DatabaseDomain $localDomain
 Local domain. More...
 
int null $maxLag
 
BagOStuff $memStash
 
string bool $readOnlyReason = false
 Reason all LBs are read-only or false if not. More...
 
BagOStuff $srvCache
 
WANObjectCache $wanCache
 

Detailed Description

A multi-database, multi-master factory for Wikimedia and similar installations.

Ignores the old configuration globals.

Definition at line 35 of file LBFactoryMulti.php.

Constructor & Destructor Documentation

◆ __construct()

Wikimedia\Rdbms\LBFactoryMulti::__construct ( array  $conf)

Template override precedence (highest => lowest):

  • templateOverridesByServer
  • masterTemplateOverrides
  • templateOverridesBySection/templateOverridesByCluster
  • externalTemplateOverrides
  • serverTemplate Overrides only work on top level keys (so nested values will not be merged).

Server config maps should be of the format Database::factory() requires. Additionally, a 'max lag' key should also be set on server maps, indicating how stale the data can be before the load balancer tries to avoid using it. The map can have 'is static' set to disable blocking replication sync checks (intended for archive servers with unchanging data).

See also
LBFactory::__construct()
Parameters
array$confAdditional parameters include:
  • hostsByName Optional (hostname => IP address) map.
  • sectionsByDB Optional map of (database => section name). For example: [ 'DEFAULT' => 'section1', 'database1' => 'section2' ]
  • sectionLoads Optional map of (section => host => load ratio); the first host in each section is the master server for that section. For example: [ 'dbmaser' => 0, 'dbreplica1' => 100, 'dbreplica2' => 100 ]
  • groupLoadsBySection Optional map of (section => group => host => load ratio); any ILoadBalancer::GROUP_GENERIC group will be ignored. For example: [ 'section1' => [ 'group1' => [ 'dbreplica3 => 100, 'dbreplica4' => 100 ] ] ]
  • groupLoadsByDB Optional (database => group => host => load ratio) map.
  • externalLoads Optional (cluster => host => load ratio) map.
  • serverTemplate server config map for Database::factory(). Note that "host", "hostName" and "load" entries will be overridden by "groupLoadsBySection" and "hostsByName".
  • externalTemplateOverrides Optional server config map overrides for external stores; respects the override precedence described above.
  • templateOverridesBySection Optional (section => server config map overrides) map; respects the override precedence described above.
  • templateOverridesByCluster Optional (external cluster => server config map overrides) map; respects the override precedence described above.
  • masterTemplateOverrides Optional server config map overrides for masters; respects the override precedence described above.
  • templateOverridesByServer Optional (host => server config map overrides) map; respects the override precedence described above and applies to both core and external storage.
  • loadMonitorClass Name of the LoadMonitor class to always use. [optional]
  • readOnlyBySection Optional map of (section name => message text or false). String values make sections read only, whereas anything else does not restrict read/write mode.

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 138 of file LBFactoryMulti.php.

Member Function Documentation

◆ forEachLB()

Wikimedia\Rdbms\LBFactoryMulti::forEachLB (   $callback,
array  $params = [] 
)

Execute a function for each currently tracked (instantiated) load balancer.

The callback is called with the load balancer as the first parameter, and $params passed as the subsequent parameters.

Parameters
callable$callback
array$params

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 239 of file LBFactoryMulti.php.

◆ getAllExternalLBs()

Wikimedia\Rdbms\LBFactoryMulti::getAllExternalLBs ( )

Get cached (tracked) load balancers for all external database clusters.

Returns
ILoadBalancer[] Map of (cluster name => ILoadBalancer)
Since
1.29

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 230 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactoryMulti\getExternalLB().

◆ getAllMainLBs()

Wikimedia\Rdbms\LBFactoryMulti::getAllMainLBs ( )

Get cached (tracked) load balancers for all main database clusters.

The default cluster name is ILoadBalancer::CLUSTER_MAIN_DEFAULT

Returns
ILoadBalancer[] Map of (cluster name => ILoadBalancer)
Since
1.29

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 219 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactoryMulti\getMainLB().

◆ getDomainDatabase()

Wikimedia\Rdbms\LBFactoryMulti::getDomainDatabase (   $domain = false)
private
Parameters
DatabaseDomain | string | bool$domainDomain ID, or false for the current domain
Returns
string

Definition at line 346 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\DatabaseDomain\newFromId().

Referenced by Wikimedia\Rdbms\LBFactoryMulti\getSectionForDomain(), and Wikimedia\Rdbms\LBFactoryMulti\newMainLB().

◆ getExternalLB()

Wikimedia\Rdbms\LBFactoryMulti::getExternalLB (   $cluster)

Get a cached (tracked) load balancer for external storage.

Parameters
string$clusterExternal storage cluster name
Returns
ILoadBalancer

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 210 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactory\getOwnershipId(), and Wikimedia\Rdbms\LBFactoryMulti\newExternalLB().

Referenced by Wikimedia\Rdbms\LBFactoryMulti\getAllExternalLBs().

◆ getMainLB()

Wikimedia\Rdbms\LBFactoryMulti::getMainLB (   $domain = false)

Get a cached (tracked) load balancer object.

Parameters
bool | string$domainDomain ID, or false for the current domain
Returns
ILoadBalancer

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 183 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactory\getOwnershipId(), Wikimedia\Rdbms\LBFactoryMulti\getSectionForDomain(), and Wikimedia\Rdbms\LBFactoryMulti\newMainLB().

Referenced by Wikimedia\Rdbms\LBFactoryMulti\getAllMainLBs().

◆ getSectionForDomain()

Wikimedia\Rdbms\LBFactoryMulti::getSectionForDomain (   $domain = false)
private

◆ makeServerArray()

Wikimedia\Rdbms\LBFactoryMulti::makeServerArray ( array  $serverTemplate,
array  $groupLoads 
)
private

Make a server array as expected by LoadBalancer::__construct()

Parameters
array$serverTemplateServer config map
int[][]$groupLoads Map of (group => host => load)
Returns
array[] List of server config maps

Definition at line 295 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactoryMulti\reindexGroupLoads().

Referenced by Wikimedia\Rdbms\LBFactoryMulti\newLoadBalancer().

◆ newExternalLB()

Wikimedia\Rdbms\LBFactoryMulti::newExternalLB (   $cluster,
  $owner = null 
)

Create a new load balancer for external storage.

The resulting object will be untracked, not chronology-protected, and the caller is responsible for cleaning it up.

This method is for only advanced usage and callers should almost always use getExternalLB() instead. This method can be useful when a table is used as a key/value store. In that cases, one might want to query it in autocommit mode (DBO_TRX off) but still use DBO_TRX transaction rounds on other tables.

Parameters
string$clusterExternal storage cluster name
int | null$ownerOwner ID of the new instance (e.g. this LBFactory ID)
Returns
ILoadBalancer

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 193 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactoryMulti\newLoadBalancer().

Referenced by Wikimedia\Rdbms\LBFactoryMulti\getExternalLB().

◆ newLoadBalancer()

Wikimedia\Rdbms\LBFactoryMulti::newLoadBalancer (   $serverTemplate,
  $groupLoads,
  $readOnlyReason,
  $owner 
)
private

Make a new load balancer object based on template and load array.

Parameters
array$serverTemplateServer config map
int[][]$groupLoads Map of (group => host => load)
string | bool$readOnlyReason
int | null$owner
Returns
LoadBalancer

Definition at line 274 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactory\$readOnlyReason, Wikimedia\Rdbms\LBFactory\baseLoadBalancerParams(), Wikimedia\Rdbms\LBFactory\initLoadBalancer(), and Wikimedia\Rdbms\LBFactoryMulti\makeServerArray().

Referenced by Wikimedia\Rdbms\LBFactoryMulti\newExternalLB(), and Wikimedia\Rdbms\LBFactoryMulti\newMainLB().

◆ newMainLB()

Wikimedia\Rdbms\LBFactoryMulti::newMainLB (   $domain = false,
  $owner = null 
)

Create a new load balancer object.

The resulting object will be untracked, not chronology-protected, and the caller is responsible for cleaning it up.

This method is for only advanced usage and callers should almost always use getMainLB() instead. This method can be useful when a table is used as a key/value store. In that cases, one might want to query it in autocommit mode (DBO_TRX off) but still use DBO_TRX transaction rounds on other tables.

Parameters
bool | string$domainDomain ID, or false for the current domain
int | null$ownerOwner ID of the new instance (e.g. this LBFactory ID)
Returns
ILoadBalancer

Implements Wikimedia\Rdbms\ILBFactory.

Definition at line 160 of file LBFactoryMulti.php.

References Wikimedia\Rdbms\LBFactoryMulti\getDomainDatabase(), Wikimedia\Rdbms\LBFactoryMulti\getSectionForDomain(), and Wikimedia\Rdbms\LBFactoryMulti\newLoadBalancer().

Referenced by Wikimedia\Rdbms\LBFactoryMulti\getMainLB().

◆ reindexGroupLoads()

Wikimedia\Rdbms\LBFactoryMulti::reindexGroupLoads ( array  $groupLoads)
private

Take a group load array indexed by group then server, and reindex it by server then group.

Parameters
int[][]$groupLoads Map of (group => host => load)
Returns
int[][] Map of (host => group => load)

Definition at line 330 of file LBFactoryMulti.php.

Referenced by Wikimedia\Rdbms\LBFactoryMulti\makeServerArray().

Member Data Documentation

◆ $externalLBs

LoadBalancer [] Wikimedia\Rdbms\LBFactoryMulti::$externalLBs = []
private

Definition at line 39 of file LBFactoryMulti.php.

◆ $externalLoads

int [][] Wikimedia\Rdbms\LBFactoryMulti::$externalLoads = []
private

Map of (cluster => host => load ratio)

Definition at line 50 of file LBFactoryMulti.php.

◆ $externalTemplateOverrides

array Wikimedia\Rdbms\LBFactoryMulti::$externalTemplateOverrides = []
private

Server config map overriding "serverTemplate" for external storage.

Definition at line 54 of file LBFactoryMulti.php.

◆ $groupLoadsByDB

int [][][] Wikimedia\Rdbms\LBFactoryMulti::$groupLoadsByDB = []
private

Map of (database => group => host => load ratio)

Definition at line 48 of file LBFactoryMulti.php.

◆ $groupLoadsBySection

int [][][] Wikimedia\Rdbms\LBFactoryMulti::$groupLoadsBySection = []
private

Map of (section => group => host => load ratio)

Definition at line 46 of file LBFactoryMulti.php.

◆ $hostsByName

string [] Wikimedia\Rdbms\LBFactoryMulti::$hostsByName = []
private

Map of (hostname => IP address)

Definition at line 42 of file LBFactoryMulti.php.

◆ $lastDomain

string Wikimedia\Rdbms\LBFactoryMulti::$lastDomain
private

Definition at line 70 of file LBFactoryMulti.php.

◆ $lastSection

string Wikimedia\Rdbms\LBFactoryMulti::$lastSection
private

◆ $loadMonitorClass

string Wikimedia\Rdbms\LBFactoryMulti::$loadMonitorClass
private

An ILoadMonitor class.

Definition at line 67 of file LBFactoryMulti.php.

◆ $mainLBs

LoadBalancer [] Wikimedia\Rdbms\LBFactoryMulti::$mainLBs = []
private

Definition at line 37 of file LBFactoryMulti.php.

◆ $masterTemplateOverrides

array Wikimedia\Rdbms\LBFactoryMulti::$masterTemplateOverrides = []
private

Server config override map for all main and external master servers.

Definition at line 60 of file LBFactoryMulti.php.

◆ $readOnlyBySection

string [] bool [] Wikimedia\Rdbms\LBFactoryMulti::$readOnlyBySection = []
private

A map of section name to read-only message.

Definition at line 64 of file LBFactoryMulti.php.

◆ $sectionsByDB

string [] Wikimedia\Rdbms\LBFactoryMulti::$sectionsByDB = []
private

Map of (database name => section name)

Definition at line 44 of file LBFactoryMulti.php.

◆ $serverTemplate

array Wikimedia\Rdbms\LBFactoryMulti::$serverTemplate = []
private

Server config map ("host", "hostName", "load", and "groupLoads" are ignored)

Definition at line 52 of file LBFactoryMulti.php.

◆ $templateOverridesByCluster

array [] Wikimedia\Rdbms\LBFactoryMulti::$templateOverridesByCluster = []
private

Map of (cluster => server config map overrides) for external storage.

Definition at line 58 of file LBFactoryMulti.php.

◆ $templateOverridesBySection

array [] Wikimedia\Rdbms\LBFactoryMulti::$templateOverridesBySection = []
private

Map of (section => server config map overrides)

Definition at line 56 of file LBFactoryMulti.php.

◆ $templateOverridesByServer

array [] Wikimedia\Rdbms\LBFactoryMulti::$templateOverridesByServer = []
private

Map of (host => server config map overrides) for main and external servers.

Definition at line 62 of file LBFactoryMulti.php.


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