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MySqlLockManager Class Reference

MySQL version of DBLockManager that supports shared locks. More...

Inheritance diagram for MySqlLockManager:
Collaboration diagram for MySqlLockManager:

Public Member Functions

 __construct (array $config)
 Construct a new instance from configuration. More...
 
- Public Member Functions inherited from DBLockManager
 __destruct ()
 Make sure remaining locks get cleared for sanity. More...
 
- Public Member Functions inherited from LockManager
 lock (array $paths, $type=self::LOCK_EX, $timeout=0)
 Lock the resources at the given abstract paths. More...
 
 lockByType (array $pathsByType, $timeout=0)
 Lock the resources at the given abstract paths. More...
 
 unlock (array $paths, $type=self::LOCK_EX)
 Unlock the resources at the given abstract paths. More...
 
 unlockByType (array $pathsByType)
 Unlock the resources at the given abstract paths. More...
 

Protected Member Functions

 doGetLocksOnServer ( $lockSrv, array $paths, $type)
 Get a connection to a lock DB and acquire locks on $paths. More...
 
 initConnection ( $lockDb, IDatabase $db)
 Do additional initialization for new lock DB connection @stable to override. More...
 
 releaseAllLocks ()
 
- Protected Member Functions inherited from DBLockManager
 cacheCheckFailures ( $lockDb)
 Checks if the DB has not recently had connection/query errors. More...
 
 cacheRecordFailure ( $lockDb)
 Log a lock request failure to the cache. More...
 
 freeLocksOnServer ( $lockSrv, array $pathsByType)
 Get a connection to a lock server and release locks on $paths.Subclasses must effectively implement this or releaseAllLocks().
Parameters
string$lockSrv
array$pathsByTypeMap of LockManager::LOCK_* constants to lists of paths
Returns
StatusValue
Stable to override More...
 
 getConnection ( $lockDb)
 Get (or reuse) a connection to a lock DB. More...
 
 getLocksOnServer ( $lockSrv, array $pathsByType)
 
 getMissKey ( $lockDb)
 Get a cache key for recent query misses for a DB. More...
 
 isServerUp ( $lockSrv)
 
- Protected Member Functions inherited from QuorumLockManager
 collectPledgeQuorum ( $bucket, callable $callback)
 Attempt to acquire pledges with the peers for a bucket. More...
 
 doLock (array $paths, $type)
 Lock resources with the given keys and lock type. More...
 
 doLockByType (array $pathsByType)
 
 doLockingRequestBucket ( $bucket, array $pathsByType)
 Attempt to acquire locks with the peers for a bucket. More...
 
 doUnlock (array $paths, $type)
 Unlock resources with the given keys and lock type. More...
 
 doUnlockByType (array $pathsByType)
 Stable to override. More...
 
 doUnlockingRequestBucket ( $bucket, array $pathsByType)
 Attempt to release locks with the peers for a bucket. More...
 
 getBucketFromPath ( $path)
 Get the bucket for resource path. More...
 
 releasePledges ( $bucket, callable $callback)
 Attempt to release pledges with the peers for a bucket. More...
 
- Protected Member Functions inherited from LockManager
 normalizePathsByType (array $pathsByType)
 Normalize the $paths array by converting LOCK_UW locks into the appropriate type and removing any duplicated paths for each lock type. More...
 
 sha1Base16Absolute ( $path)
 Get the base 16 SHA-1 of a string, padded to 31 digits. More...
 
 sha1Base36Absolute ( $path)
 Get the base 36 SHA-1 of a string, padded to 31 digits. More...
 

Protected Attributes

array $lockTypeMap
 Mapping of lock types to the type actually used. More...
 
- Protected Attributes inherited from DBLockManager
IDatabase[] $conns = []
 Map Database connections (DB name => Database) More...
 
array[] IDatabase[] $dbServers
 Map of (DB names => server config or IDatabase) More...
 
 $lockExpiry
 
 $safeDelay
 
BagOStuff $statusCache
 
- Protected Attributes inherited from QuorumLockManager
array $degradedBuckets = []
 Map of degraded buckets. More...
 
array $srvsByBucket = []
 Map of bucket indexes to peer server lists. More...
 
- Protected Attributes inherited from LockManager
 $domain
 
array $locksHeld = []
 Map of (resource path => lock type => count) More...
 
 $lockTTL
 
array $lockTypeMap
 Mapping of lock types to the type actually used. More...
 
LoggerInterface $logger
 
string $session
 Random 32-char hex number. More...
 

Additional Inherited Members

- Public Attributes inherited from LockManager
const LOCK_EX = 3
 
const LOCK_SH = 1
 Lock types; stronger locks have higher values. More...
 
const LOCK_UW = 2
 

Detailed Description

MySQL version of DBLockManager that supports shared locks.

Do NOT use this on connection handles that are also being used for anything else as the transaction isolation will be wrong and all the other changes will get rolled back when the locks release!

All lock servers must have the innodb table defined in maintenance/locking/filelocks.sql. All locks are non-blocking, which avoids deadlocks.

Definition at line 18 of file MySqlLockManager.php.

Constructor & Destructor Documentation

◆ __construct()

MySqlLockManager::__construct ( array  $config)

Construct a new instance from configuration.

Stable to call

Parameters
array$configParameters include:
  • dbServers : Associative array of DB names to server configuration. Configuration is an associative array that includes:
    • host : DB server name
    • dbname : DB name
    • type : DB type (mysql,postgres,...)
    • user : DB user
    • password : DB user password
    • tablePrefix : DB table prefix
    • flags : DB flags; bitfield of IDatabase::DBO_* constants
  • dbsByBucket : Array of 1-16 consecutive integer keys, starting from 0, each having an odd-numbered list of DB names (peers) as values.
  • lockExpiry : Lock timeout (seconds) for dropped connections. [optional] This tells the DB server how long to wait before assuming connection failure and releasing all the locks for a session.
  • srvCache : A BagOStuff instance using APC or the like.

Reimplemented from DBLockManager.

Definition at line 26 of file MySqlLockManager.php.

Member Function Documentation

◆ doGetLocksOnServer()

MySqlLockManager::doGetLocksOnServer (   $lockSrv,
array  $paths,
  $type 
)
protected

Get a connection to a lock DB and acquire locks on $paths.

This does not use GET_LOCK() per https://bugs.mysql.com/bug.php?id=1118.

See also
DBLockManager::getLocksOnServer()
Parameters
string$lockSrv
array$paths
string$type
Returns
StatusValue

Reimplemented from DBLockManager.

Definition at line 49 of file MySqlLockManager.php.

References $keys, $path, LockManager\$session, $type, DBLockManager\getConnection(), StatusValue\newGood(), and LockManager\sha1Base36Absolute().

◆ initConnection()

MySqlLockManager::initConnection (   $lockDb,
IDatabase  $db 
)
protected

Do additional initialization for new lock DB connection @stable to override.

Parameters
string$lockDb
IDatabase$db
Exceptions
DBError

Reimplemented from DBLockManager.

Definition at line 32 of file MySqlLockManager.php.

References Wikimedia\Rdbms\IDatabase\query(), and Wikimedia\Rdbms\IDatabase\startAtomic().

◆ releaseAllLocks()

MySqlLockManager::releaseAllLocks ( )
protected
See also
QuorumLockManager::releaseAllLocks()
Returns
StatusValue

Reimplemented from QuorumLockManager.

Definition at line 126 of file MySqlLockManager.php.

References StatusValue\newGood().

Member Data Documentation

◆ $lockTypeMap

array MySqlLockManager::$lockTypeMap
protected
Initial value:
= [
self::LOCK_SH => self::LOCK_SH,
self::LOCK_UW => self::LOCK_SH,
self::LOCK_EX => self::LOCK_EX
]

Mapping of lock types to the type actually used.

Definition at line 20 of file MySqlLockManager.php.


The documentation for this class was generated from the following file:
LockManager\LOCK_SH
const LOCK_SH
Lock types; stronger locks have higher values.
Definition: LockManager.php:69
LockManager\LOCK_EX
const LOCK_EX
Definition: LockManager.php:71