A cache class that replicates all writes to multiple child caches. More...

Inheritance diagram for MultiWriteBagOStuff:

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Collaboration diagram for MultiWriteBagOStuff:

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Public Member Functions
	__construct ( $params)
	Stable to call.

	add ( $key, $value, $exptime=0, $flags=0)
	Insert an item if it does not already exist.

	addBusyCallback (callable $workCallback)
	Let a callback be run to avoid wasting time on special blocking calls.

	changeTTL ( $key, $exptime=0, $flags=0)
	Change the expiration on a key if it exists.

	changeTTLMulti (array $keys, $exptime, $flags=0)
	Change the expiration of multiple keys that exist.

	clearLastError ()
	Clear the "last error" registry.

	decr ( $key, $value=1, $flags=0)
	Decrease stored value of $key by $value while preserving its TTL.

	delete ( $key, $flags=0)
	Delete an item.

	deleteMulti (array $data, $flags=0)
	Batch deletion.

	deleteObjectsExpiringBefore ( $timestamp, callable $progress=null, $limit=INF)
	Delete all objects expiring before a certain date.

	get ( $key, $flags=0)
	Get an item with the given key.

	getLastError ()
	Get the "last error" registered; clearLastError() should be called manually.

	getMulti (array $keys, $flags=0)
	Get an associative array containing the item for each of the keys that have items.

	incr ( $key, $value=1, $flags=0)
	Increase stored value of $key by $value while preserving its TTL.

	incrWithInit ( $key, $exptime, $value=1, $init=null, $flags=0)
	Increase the value of the given key (no TTL change) if it exists or create it otherwise.

	lock ( $key, $timeout=6, $expiry=6, $rclass='')
	Acquire an advisory lock on a key string.

	makeGlobalKey ( $class,... $components)
	Make a global cache key.

	makeKey ( $class,... $components)
	Make a cache key, scoped to this instance's keyspace.

	makeKeyInternal ( $keyspace, $args)
	Construct a cache key.

	merge ( $key, callable $callback, $exptime=0, $attempts=10, $flags=0)
	Merge changes into the existing cache value (possibly creating a new one)

	set ( $key, $value, $exptime=0, $flags=0)
	Set an item.

	setDebug ( $enabled)

	setMockTime (&$time)

	setMulti (array $data, $exptime=0, $flags=0)
	Batch insertion/replace.

	setNewPreparedValues (array $valueByKey)
	Prepare values for storage and get their serialized sizes, or, estimate those sizes.

	unlock ( $key)
	Release an advisory lock on a key string.

Public Member Functions inherited from BagOStuff
	__construct (array $params=[])
	Parameters include:

	getCurrentTime ()

	getLogger ()

	getQoS ( $flag)

	getScopedLock ( $key, $timeout=6, $expiry=30, $rclass='')
	Get a lightweight exclusive self-unlocking lock.

	getSegmentationSize ()

	getSegmentedValueMaxSize ()

	getWithSetCallback ( $key, $exptime, $callback, $flags=0)
	Get an item with the given key, regenerating and setting it if not found.

	setLogger (LoggerInterface $logger)

Protected Member Functions
	doWrite ( $indexes, $asyncWrites, $method, array $args)
	Apply a write method to the backing caches specified by $indexes (in order)

	usesAsyncWritesGivenFlags ( $flags)

Protected Member Functions inherited from BagOStuff
	fieldHasFlags ( $field, $flags)

	mergeFlagMaps (array $bags)
	Merge the flag maps of one or more BagOStuff objects into a "lowest common denominator" map.

Protected Attributes
bool	$asyncWrites = false
	Use async secondary writes.

int[]	$cacheIndexes = []
	List of all backing cache indexes.

BagOStuff[]	$caches

Protected Attributes inherited from BagOStuff
callable null	$asyncHandler

int[]	$attrMap = []
	Map of (ATTR_* class constant => QOS_* class constant)

bool	$debugMode = false

LoggerInterface	$logger

Static Private Attributes
static int	$UPGRADE_TTL = 3600
	TTL when a key is copied to a higher cache tier.

Additional Inherited Members
Public Attributes inherited from BagOStuff
const	READ_LATEST = 1
	Bitfield constants for get()/getMulti(); these are only advisory.

const	READ_VERIFIED = 2

const	WRITE_ALLOW_SEGMENTS = 16

const	WRITE_BACKGROUND = 64

const	WRITE_CACHE_ONLY = 8

const	WRITE_PRUNE_SEGMENTS = 32

const	WRITE_SYNC = 4
	Bitfield constants for set()/merge(); these are only advisory.

Detailed Description

A cache class that replicates all writes to multiple child caches.

Reads are implemented by reading from the caches in the order they are given in the configuration until a cache gives a positive result.

Note that cache key construction will use the first cache backend in the list, so make sure that the other backends can handle such keys (e.g. via encoding).

@newable

Definition at line 36 of file MultiWriteBagOStuff.php.

Constructor & Destructor Documentation

◆ __construct()

MultiWriteBagOStuff::__construct ( $params )

Stable to call.

Parameters

array

$params

caches: A numbered array of either ObjectFactory::getObjectFromSpec arrays yielding BagOStuff objects or direct BagOStuff objects. If using the former, the 'args' field must be set. The first cache is the primary one, being the first to be read in the fallback chain. Writes happen to all stores in the order they are defined. However, lock()/unlock() calls only use the primary store.
replication: Either 'sync' or 'async'. This controls whether writes to secondary stores are deferred when possible. To use 'async' writes requires the 'asyncHandler' option to be set as well. Async writes can increase the chance of some race conditions or cause keys to expire seconds later than expected. It is safe to use for modules when cached values: are immutable, invalidation uses logical TTLs, invalidation uses etag/timestamp validation against the DB, or merge() is used to handle races. -param array{caches:array<int,array|BagOStuff>,replication:string} $params

Exceptions

InvalidArgumentException

Definition at line 68 of file MultiWriteBagOStuff.php.

References BagOStuff\mergeFlagMaps().

Member Function Documentation

◆ add()

MultiWriteBagOStuff::add	(	$key,
		$value,
		$exptime = `0`,
		$flags = `0`
	)

Insert an item if it does not already exist.

Parameters

string	$key
mixed	$value
int	$exptime
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

Returns: bool Success

Reimplemented from BagOStuff.

Definition at line 164 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ addBusyCallback()

MultiWriteBagOStuff::addBusyCallback ( callable $workCallback )

Let a callback be run to avoid wasting time on special blocking calls.

The callbacks may or may not be called ever, in any particular order. They are likely to be invoked when something WRITE_SYNC is used used. They should follow a caching pattern as shown below, so that any code using the work will get it's result no matter what happens.

$result = null;
$workCallback = function () use ( &$result ) {
    if ( !$result ) {
        $result = ....
    }
    return $result;
}

Parameters

callable $workCallback

Since: 1.28

Reimplemented from BagOStuff.

Definition at line 367 of file MultiWriteBagOStuff.php.

◆ changeTTL()

MultiWriteBagOStuff::changeTTL	(	$key,
		$exptime = `0`,
		$flags = `0`
	)

Change the expiration on a key if it exists.

If an expiry in the past is given then the key will immediately be expired

For large values written using WRITE_ALLOW_SEGMENTS, this only changes the TTL of the main segment list key. While lowering the TTL of the segment list key has the effect of functionally lowering the TTL of the key, it might leave unused blobs in cache for longer. Raising the TTL of such keys is not effective, since the expiration of a single segment key effectively expires the entire value.

Parameters

string	$key
int	$exptime	TTL or UNIX timestamp
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

Returns: bool Success Returns false on failure or if the item does not exist

Since: 1.28

Reimplemented from BagOStuff.

Definition at line 197 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ changeTTLMulti()

MultiWriteBagOStuff::changeTTLMulti	(	array	$keys,
			$exptime,
			$flags = `0`
	)

Change the expiration of multiple keys that exist.

See also: BagOStuff::changeTTL()

Parameters

string[]	$keys	List of keys
int	$exptime	TTL or UNIX timestamp
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

Returns: bool Success

Since: 1.34

Reimplemented from BagOStuff.

Definition at line 262 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ clearLastError()

MultiWriteBagOStuff::clearLastError ( )

Clear the "last error" registry.

Since: 1.23

Reimplemented from BagOStuff.

Definition at line 302 of file MultiWriteBagOStuff.php.

◆ decr()

MultiWriteBagOStuff::decr	(	$key,
		$value = `1`,
		$flags = `0`
	)

Decrease stored value of $key by $value while preserving its TTL.

Parameters

string	$key
int	$value	Value to subtract from $key (default: 1) [optional]
int	$flags	Bit field of class WRITE_* constants [optional]

Returns: int|bool New value or false on failure

Reimplemented from BagOStuff.

Definition at line 280 of file MultiWriteBagOStuff.php.

References doWrite().

◆ delete()

MultiWriteBagOStuff::delete	(	$key,
		$flags = `0`
	)

Delete an item.

For large values written using WRITE_ALLOW_SEGMENTS, this only deletes the main segment list key unless WRITE_PRUNE_SEGMENTS is in the flags. While deleting the segment list key has the effect of functionally deleting the key, it leaves unused blobs in cache.

Parameters

string $key

Returns: bool True if the item was deleted or not found, false on failure

Parameters

int $flags Bitfield of BagOStuff::WRITE_* constants

Reimplemented from BagOStuff.

Definition at line 155 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ deleteMulti()

MultiWriteBagOStuff::deleteMulti	(	array	$keys,
			$flags = `0`
	)

Batch deletion.

This does not support WRITE_ALLOW_SEGMENTS to avoid excessive read I/O

WRITE_BACKGROUND can be used for bulk deletion where the response is not vital

Parameters

string[]	$keys	List of keys
int	$flags	Bitfield of BagOStuff::WRITE_* constants

Returns: bool Success

Since: 1.33

Reimplemented from BagOStuff.

Definition at line 253 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ deleteObjectsExpiringBefore()

MultiWriteBagOStuff::deleteObjectsExpiringBefore	(		$timestamp,
		callable	$progress = `null`,
			$limit = `INF`
	)

Delete all objects expiring before a certain date.

Parameters

string \| int	$timestamp	The reference date in MW or TS_UNIX format
callable \| null	$progress	Optional, a function which will be called regularly during long-running operations with the percentage progress as the first parameter. [optional]
int	$limit	Maximum number of keys to delete [default: INF]

Returns: bool Success; false if unimplemented

Reimplemented from BagOStuff.

Definition at line 216 of file MultiWriteBagOStuff.php.

References $cache.

◆ doWrite()

MultiWriteBagOStuff::doWrite	(		$indexes,
			$asyncWrites,
			$method,
		array	$args
	)

protected

Apply a write method to the backing caches specified by $indexes (in order)

Parameters

int[]	$indexes	List of backing cache indexes
bool	$asyncWrites
string	$method	Method name of backing caches
array	$args	Arguments to the method of backing caches

Returns: bool

Definition at line 315 of file MultiWriteBagOStuff.php.

References $args, BagOStuff\$asyncHandler, $asyncWrites, $cache, BagOStuff\$logger, serialize(), and unserialize().

Referenced by add(), changeTTL(), changeTTLMulti(), decr(), delete(), deleteMulti(), get(), incr(), incrWithInit(), merge(), set(), and setMulti().

◆ get()

MultiWriteBagOStuff::get	(	$key,
		$flags = `0`
	)

Get an item with the given key.

If the key includes a deterministic input hash (e.g. the key can only have the correct value) or complete staleness checks are handled by the caller (e.g. nothing relies on the TTL), then the READ_VERIFIED flag should be set. This lets tiered backends know they can safely upgrade a cached value to higher tiers using standard TTLs.

Parameters

string	$key
int	$flags	Bitfield of BagOStuff::READ_* constants [optional]

Returns: mixed Returns false on failure or if the item does not exist

Reimplemented from BagOStuff.

Definition at line 110 of file MultiWriteBagOStuff.php.

References $cache, doWrite(), and BagOStuff\fieldHasFlags().

◆ getLastError()

MultiWriteBagOStuff::getLastError ( )

Get the "last error" registered; clearLastError() should be called manually.

Returns: int ERR_* constant for the "last error" registry

Since: 1.23

Reimplemented from BagOStuff.

Definition at line 298 of file MultiWriteBagOStuff.php.

◆ getMulti()

MultiWriteBagOStuff::getMulti	(	array	$keys,
			$flags = `0`
	)

Get an associative array containing the item for each of the keys that have items.

Parameters

string[]	$keys	List of keys
int	$flags	Bitfield; supports READ_LATEST [optional]

Returns: mixed[] Map of (key => value) for existing keys

Reimplemented from BagOStuff.

Definition at line 231 of file MultiWriteBagOStuff.php.

References $keys, and $res.

◆ incr()

MultiWriteBagOStuff::incr	(	$key,
		$value = `1`,
		$flags = `0`
	)

Increase stored value of $key by $value while preserving its TTL.

Parameters

string	$key	Key to increase
int	$value	Value to add to $key (default: 1) [optional]
int	$flags	Bit field of class WRITE_* constants [optional]

Returns: int|bool New value or false on failure

Reimplemented from BagOStuff.

Definition at line 271 of file MultiWriteBagOStuff.php.

References doWrite().

◆ incrWithInit()

MultiWriteBagOStuff::incrWithInit	(	$key,
		$exptime,
		$value = `1`,
		$init = `null`,
		$flags = `0`
	)

Increase the value of the given key (no TTL change) if it exists or create it otherwise.

This will create the key with the value $init and TTL $exptime instead if not present. Callers should make sure that both ($init - $value) and $exptime are invariants for all operations to any given key. The value of $init should be at least that of $value.

Parameters

string	$key	Key built via makeKey() or makeGlobalKey()
int	$exptime	Time-to-live (in seconds) or a UNIX timestamp expiration
int	$value	Amount to increase the key value by [default: 1]
int \| null	$init	Value to initialize the key to if it does not exist [default: $value]
int	$flags	Bit field of class WRITE_* constants [optional]

Returns: int|bool New value or false on failure

Since: 1.24

Reimplemented from BagOStuff.

Definition at line 289 of file MultiWriteBagOStuff.php.

References doWrite().

◆ lock()

MultiWriteBagOStuff::lock	(	$key,
		$timeout = `6`,
		$expiry = `6`,
		$rclass = `''`
	)

Acquire an advisory lock on a key string.

Note that if reentry is enabled, duplicate calls ignore $expiry

Parameters

string	$key
int	$timeout	Lock wait timeout; 0 for non-blocking [optional]
int	$expiry	Lock expiry [optional]; 1 day maximum
string	$rclass	Allow reentry if set and the current lock used this value

Returns: bool Success

Reimplemented from BagOStuff.

Definition at line 206 of file MultiWriteBagOStuff.php.

◆ makeGlobalKey()

MultiWriteBagOStuff::makeGlobalKey	(	$class,
		$components
	)

Make a global cache key.

Since: 1.27

Parameters

string	$class	Key class
	string\|int	...$components Key components (starting with a key collection name)

Returns: string Colon-delimited list of $keyspace followed by escaped components

Reimplemented from BagOStuff.

Definition at line 363 of file MultiWriteBagOStuff.php.

◆ makeKey()

MultiWriteBagOStuff::makeKey	(	$class,
		$components
	)

Make a cache key, scoped to this instance's keyspace.

Since: 1.27

Parameters

string	$class	Key class
	string\|int	...$components Key components (starting with a key collection name)

Returns: string Colon-delimited list of $keyspace followed by escaped components

Reimplemented from BagOStuff.

Definition at line 359 of file MultiWriteBagOStuff.php.

◆ makeKeyInternal()

MultiWriteBagOStuff::makeKeyInternal	(	$keyspace,
		$args
	)

Construct a cache key.

Since: 1.27

Parameters

string	$keyspace
array	$args

Returns: string Colon-delimited list of $keyspace followed by escaped components of $args

Reimplemented from BagOStuff.

Definition at line 355 of file MultiWriteBagOStuff.php.

References $args.

◆ merge()

MultiWriteBagOStuff::merge	(		$key,
		callable	$callback,
			$exptime = `0`,
			$attempts = `10`,
			$flags = `0`
	)

Merge changes into the existing cache value (possibly creating a new one)

The callback function returns the new value given the current value (which will be false if not present), and takes the arguments: (this BagOStuff, cache key, current value, TTL). The TTL parameter is reference set to $exptime. It can be overriden in the callback. Nothing is stored nor deleted if the callback returns false.

Parameters

string	$key
callable	$callback	Callback method to be executed
int	$exptime	Either an interval in seconds or a unix timestamp for expiry
int	$attempts	The amount of times to attempt a merge in case of failure
int	$flags	Bitfield of BagOStuff::WRITE_* constants

Returns: bool Success

Exceptions

InvalidArgumentException

Reimplemented from BagOStuff.

Definition at line 188 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ set()

MultiWriteBagOStuff::set	(	$key,
		$value,
		$exptime = `0`,
		$flags = `0`
	)

Set an item.

Parameters

string	$key
mixed	$value
int	$exptime	Either an interval in seconds or a unix timestamp for expiry
int	$flags	Bitfield of BagOStuff::WRITE_* constants

Returns: bool Success

Reimplemented from BagOStuff.

Definition at line 146 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ setDebug()

MultiWriteBagOStuff::setDebug ( $enabled )

Parameters

bool $enabled

Reimplemented from BagOStuff.

Definition at line 103 of file MultiWriteBagOStuff.php.

References $cache.

◆ setMockTime()

MultiWriteBagOStuff::setMockTime ( & $time )

Reimplemented from BagOStuff.

Definition at line 375 of file MultiWriteBagOStuff.php.

References $cache.

◆ setMulti()

MultiWriteBagOStuff::setMulti	(	array	$data,
			$exptime = `0`,
			$flags = `0`
	)

Batch insertion/replace.

This does not support WRITE_ALLOW_SEGMENTS to avoid excessive read I/O

WRITE_BACKGROUND can be used for bulk insertion where the response is not vital

Parameters

mixed[]	$data	Map of (key => value)
int	$exptime	Either an interval in seconds or a unix timestamp for expiry
int	$flags	Bitfield of BagOStuff::WRITE_* constants (since 1.33)

Returns: bool Success

Since: 1.24

Reimplemented from BagOStuff.

Definition at line 244 of file MultiWriteBagOStuff.php.

References doWrite(), and usesAsyncWritesGivenFlags().

◆ setNewPreparedValues()

MultiWriteBagOStuff::setNewPreparedValues ( array $valueByKey )

Prepare values for storage and get their serialized sizes, or, estimate those sizes.

All previously prepared values will be cleared. Each of the new prepared values will be individually cleared as they get used by write operations for that key. This is done to avoid unchecked growth in PHP memory usage.

Example usage:

$valueByKey = [ $key1 => $value1, $key2 => $value2, $key3 => $value3 ];
$cache->setNewPreparedValues( $valueByKey );
$cache->set( $key1, $value1, $cache::TTL_HOUR );
$cache->setMulti( [ $key2 => $value2, $key3 => $value3 ], $cache::TTL_HOUR );

This is only useful if the caller needs an estimate of the serialized object sizes. The caller cannot know the serialization format and even if it did, it could be expensive to serialize complex values twice just to get the size information before writing them to cache. This method solves both problems by making the cache instance do the serialization and having it reuse the result when the cache write happens.

Parameters

array $valueByKey Map of (cache key => PHP variable value to serialize)

Returns: int[]|null[] Corresponding list of size estimates (null for invalid values)

Since: 1.35

Reimplemented from BagOStuff.

Definition at line 371 of file MultiWriteBagOStuff.php.

◆ unlock()

MultiWriteBagOStuff::unlock ( $key )

Release an advisory lock on a key string.

Parameters

string $key

Returns: bool Success

Reimplemented from BagOStuff.

Definition at line 211 of file MultiWriteBagOStuff.php.

◆ usesAsyncWritesGivenFlags()

MultiWriteBagOStuff::usesAsyncWritesGivenFlags ( $flags )

protected

Parameters

int $flags

Returns: bool

Definition at line 351 of file MultiWriteBagOStuff.php.

References $asyncWrites, and BagOStuff\fieldHasFlags().

Referenced by add(), changeTTL(), changeTTLMulti(), delete(), deleteMulti(), merge(), set(), and setMulti().

Member Data Documentation

◆ $asyncWrites

bool MultiWriteBagOStuff::$asyncWrites = false

protected

Use async secondary writes.

Definition at line 40 of file MultiWriteBagOStuff.php.

Referenced by doWrite(), and usesAsyncWritesGivenFlags().

◆ $cacheIndexes

int [] MultiWriteBagOStuff::$cacheIndexes = []

protected

List of all backing cache indexes.

Definition at line 42 of file MultiWriteBagOStuff.php.

◆ $caches

BagOStuff [] MultiWriteBagOStuff::$caches

protected

Definition at line 38 of file MultiWriteBagOStuff.php.

◆ $UPGRADE_TTL

int MultiWriteBagOStuff::$UPGRADE_TTL = 3600

staticprivate

TTL when a key is copied to a higher cache tier.

Definition at line 45 of file MultiWriteBagOStuff.php.

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

includes/libs/objectcache/MultiWriteBagOStuff.php

Public Member Functions

Protected Member Functions

Protected Attributes

Static Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

Member Function Documentation

◆ add()

◆ addBusyCallback()

◆ changeTTL()

◆ changeTTLMulti()

◆ clearLastError()

◆ decr()

◆ delete()

◆ deleteMulti()

◆ deleteObjectsExpiringBefore()

◆ doWrite()

◆ get()

◆ getLastError()

◆ getMulti()

◆ incr()

◆ incrWithInit()

◆ lock()

◆ makeGlobalKey()

◆ makeKey()

◆ makeKeyInternal()

◆ merge()

◆ set()

◆ setDebug()

◆ setMockTime()

◆ setMulti()

◆ setNewPreparedValues()

◆ unlock()

◆ usesAsyncWritesGivenFlags()

Member Data Documentation

◆ $asyncWrites

◆ $cacheIndexes

◆ $caches

◆ $UPGRADE_TTL