MediaWiki REL1_40
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A cache class that directs writes to one set of servers and reads to another. More...
Inherits BagOStuff.
Public Member Functions | |
__construct ( $params) | |
Constructor. | |
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 an item. | |
changeTTLMulti (array $keys, $exptime, $flags=0) | |
Change the expiration of multiple items. | |
delete ( $key, $flags=0) | |
Delete an item if it exists. | |
deleteMulti (array $keys, $flags=0) | |
Delete a batch of items. | |
deleteObjectsExpiringBefore ( $timestamp, callable $progress=null, $limit=INF, string $tag=null) | |
Delete all objects expiring before a certain date. | |
get ( $key, $flags=0) | |
Get an item. | |
getMulti (array $keys, $flags=0) | |
Get a batch of items. | |
incrWithInit ( $key, $exptime, $step=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, $exptime=6, $rclass='') | |
Acquire an advisory lock on a key string, exclusive to the caller. | |
makeGlobalKey ( $collection,... $components) | |
Make a cache key for the default keyspace and given components. | |
makeKey ( $collection,... $components) | |
Make a cache key for the global keyspace and given components. | |
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, $flags=0) | |
Set an item. | |
setMockTime (&$time) | |
setMulti (array $valueByKey, $exptime=0, $flags=0) | |
Set a batch of items. | |
unlock ( $key) | |
Release an advisory lock on a key string. | |
Public Member Functions inherited from BagOStuff | |
__construct (array $params=[]) | |
clearLastError () | |
Clear the "last error" registry. | |
getCurrentTime () | |
getLastError ( $watchPoint=0) | |
Get the "last error" registry. | |
getLogger () | |
getQoS ( $flag) | |
getScopedLock ( $key, $timeout=6, $exptime=30, $rclass='') | |
Get a lightweight exclusive self-unlocking lock. | |
getSegmentationSize () | |
getSegmentedValueMaxSize () | |
getWithSetCallback ( $key, $exptime, $callback, $flags=0) | |
Get an item, regenerating and setting it if not found. | |
isKeyGlobal ( $key) | |
Check whether a cache key is in the global keyspace. | |
registerWrapperInfoForStats (string $prefixComponent, string $statsGroup, callable $collectionCallback) | |
Register info about a caching layer class that uses BagOStuff as a backing store. | |
setLogger (LoggerInterface $logger) | |
setNewPreparedValues (array $valueByKey) | |
Stage a set of new key values for storage and estimate the amount of bytes needed. | |
watchErrors () | |
Get a "watch point" token that can be used to get the "last error" to occur after now. | |
Protected Member Functions | |
convertGenericKey ( $key) | |
Convert a "generic" reversible cache key into one for this cache. | |
makeKeyInternal ( $keyspace, $components) | |
Protected Member Functions inherited from BagOStuff | |
componentsFromGenericKey ( $key) | |
Extract the components from a "generic" reversible cache key. | |
determineKeyPrefixForStats ( $key) | |
fieldHasFlags ( $field, $flags) | |
genericKeyFromComponents (... $components) | |
At a minimum, there must be a keyspace and collection name component. | |
mergeFlagMaps (array $bags) | |
Merge the flag maps of one or more BagOStuff objects into a "lowest common denominator" map. | |
proxyCall (string $method, int $arg0Sig, int $resSig, array $genericArgs, BagOStuff $wrapper) | |
Call a method on behalf of wrapper BagOStuff instance that uses "generic" keys. | |
setLastError ( $error) | |
Set the "last error" registry due to a problem encountered during an attempted operation. | |
Additional Inherited Members | |
Public Attributes inherited from BagOStuff | |
const | MAX_CONFLICTS_ONE = 1 |
Abort after the first merge conflict. | |
const | READ_LATEST = 1 |
Bitfield constants for get()/getMulti(); these are only advisory. | |
const | READ_VERIFIED = 2 |
Promise that the caller handles detection of staleness. | |
const | WRITE_ALLOW_SEGMENTS = 16 |
Allow partitioning of the value if it is a large string. | |
const | WRITE_BACKGROUND = 64 |
If supported, do not block on write operation completion; instead, treat writes as succesful based on whether they could be buffered. | |
const | WRITE_CACHE_ONLY = 8 |
Bitfield constants for set()/merge(); these are only advisory. | |
const | WRITE_PRUNE_SEGMENTS = 32 |
Delete all the segments if the value is partitioned. | |
Public Attributes inherited from Wikimedia\LightweightObjectStore\StorageAwareness | |
const | ATTR_DURABILITY = 2 |
Durability of writes; see QOS_DURABILITY_* (higher means stronger) | |
const | ATTR_EMULATION = 1 |
Emulation/fallback mode; see QOS_EMULATION_*; higher is better. | |
const | ERR_NO_RESPONSE = 1 |
Storage medium failed to yield a complete response to an operation. | |
const | ERR_NONE = 0 |
No storage medium error. | |
const | ERR_UNEXPECTED = 3 |
Storage medium operation failed due to usage limitations or an I/O error. | |
const | ERR_UNREACHABLE = 2 |
Storage medium could not be reached to establish a connection. | |
const | QOS_DURABILITY_DISK = 4 |
Data is saved to disk and writes do not usually block on fsync() | |
const | QOS_DURABILITY_NONE = 1 |
Data is never saved to begin with (blackhole store) | |
const | QOS_DURABILITY_RDBMS = 5 |
Data is saved to disk and writes usually block on fsync(), like a standard RDBMS. | |
const | QOS_DURABILITY_SCRIPT = 2 |
Data is lost at the end of the current web request or CLI script. | |
const | QOS_DURABILITY_SERVICE = 3 |
Data is lost once the service storing the data restarts. | |
const | QOS_EMULATION_SQL = 1 |
Fallback disk-based SQL store. | |
const | QOS_UNKNOWN = INF |
Generic "unknown" value; useful for comparisons (always "good enough") | |
Protected Attributes inherited from BagOStuff | |
callable null | $asyncHandler |
int[] | $attrMap = [] |
Map of (BagOStuff:ATTR_* constant => BagOStuff:QOS_* constant) | |
string | $keyspace |
Default keyspace; used by makeKey() | |
int | $lastError = self::ERR_NONE |
BagOStuff:ERR_* constant of the last error that occurred. | |
int | $lastErrorId = 0 |
Error event sequence number of the last error that occurred. | |
LoggerInterface | $logger |
StatsdDataFactoryInterface | $stats |
array< string, array > | $wrapperInfoByPrefix = [] |
Cache key processing callbacks and info for metrics. | |
Static Protected Attributes inherited from BagOStuff | |
static int | $nextErrorMonitorId = 1 |
Next sequence number to use for watch/error events. | |
A cache class that directs writes to one set of servers and reads to another.
This assumes that the servers used for reads are setup to replica DB those that writes go to. This can easily be used with redis for example.
In the WAN scenario (e.g. multi-datacenter case), this is useful when writes are rare or they usually take place in the primary datacenter.
Definition at line 34 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::__construct | ( | $params | ) |
Constructor.
Parameters are:
array | $params |
InvalidArgumentException |
Definition at line 60 of file ReplicatedBagOStuff.php.
References BagOStuff\mergeFlagMaps().
ReplicatedBagOStuff::add | ( | $key, | |
$value, | |||
$exptime = 0, | |||
$flags = 0 ) |
Insert an item if it does not already exist.
string | $key | |
mixed | $value | |
int | $exptime | |
int | $flags | Bitfield of BagOStuff::WRITE_* constants (since 1.33) |
Reimplemented from BagOStuff.
Definition at line 124 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::addBusyCallback | ( | callable | $workCallback | ) |
Let a callback be run to avoid wasting time on special blocking calls.
This is hard-deprecated and non-functional since 1.39. The callback will not be called.
callable | $workCallback |
Reimplemented from BagOStuff.
Definition at line 279 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::changeTTL | ( | $key, | |
$exptime = 0, | |||
$flags = 0 ) |
Change the expiration on an item.
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.
string | $key | |
int | $exptime | TTL or UNIX timestamp |
int | $flags | Bitfield of BagOStuff::WRITE_* constants (since 1.33) |
Reimplemented from BagOStuff.
Definition at line 148 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::changeTTLMulti | ( | array | $keys, |
$exptime, | |||
$flags = 0 ) |
Change the expiration of multiple items.
string[] | $keys | List of keys |
int | $exptime | TTL or UNIX timestamp |
int | $flags | Bitfield of BagOStuff::WRITE_* constants (since 1.33) |
Reimplemented from BagOStuff.
Definition at line 238 of file ReplicatedBagOStuff.php.
References $keys.
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protected |
Convert a "generic" reversible cache key into one for this cache.
string | $key | Keyspace-prepended list of encoded components as a colon-separated value |
Reimplemented from BagOStuff.
Definition at line 274 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::delete | ( | $key, | |
$flags = 0 ) |
Delete an item if it exists.
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.
string | $key | |
int | $flags | Bitfield of BagOStuff::WRITE_* constants |
Reimplemented from BagOStuff.
Definition at line 112 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::deleteMulti | ( | array | $keys, |
$flags = 0 ) |
Delete a batch of items.
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
string[] | $keys | List of keys |
int | $flags | Bitfield of BagOStuff::WRITE_* constants |
Reimplemented from BagOStuff.
Definition at line 226 of file ReplicatedBagOStuff.php.
References $keys.
ReplicatedBagOStuff::deleteObjectsExpiringBefore | ( | $timestamp, | |
callable | $progress = null, | ||
$limit = INF, | |||
string | $tag = null ) |
Delete all objects expiring before a certain date.
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 | float | $limit | Maximum number of keys to delete [default: INF] |
string | null | $tag | Tag to purge a single shard only. This is only supported when server tags are used in configuration. |
Reimplemented from BagOStuff.
Definition at line 180 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::get | ( | $key, | |
$flags = 0 ) |
Get an item.
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.
string | $key | |
int | $flags | Bitfield of BagOStuff::READ_* constants [optional] |
Reimplemented from BagOStuff.
Definition at line 81 of file ReplicatedBagOStuff.php.
References BagOStuff\fieldHasFlags().
ReplicatedBagOStuff::getMulti | ( | array | $keys, |
$flags = 0 ) |
Get a batch of items.
string[] | $keys | List of keys |
int | $flags | Bitfield; supports READ_LATEST [optional] |
Reimplemented from BagOStuff.
Definition at line 195 of file ReplicatedBagOStuff.php.
References $keys, and BagOStuff\fieldHasFlags().
ReplicatedBagOStuff::incrWithInit | ( | $key, | |
$exptime, | |||
$step = 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 - $step) and $exptime are invariants for all operations to any given key. The value of $init should be at least that of $step.
The new value is returned, except if the WRITE_BACKGROUND flag is given, in which case the handler may choose to return true to indicate that the operation has been dispatched.
string | $key | Key built via makeKey() or makeGlobalKey() |
int | $exptime | Time-to-live (in seconds) or a UNIX timestamp expiration |
int | $step | Amount to increase the key value by [default: 1] |
int | null | $init | Value to initialize the key to if it does not exist [default: $step] |
int | $flags | Bit field of class WRITE_* constants [optional] |
Reimplemented from BagOStuff.
Definition at line 250 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::lock | ( | $key, | |
$timeout = 6, | |||
$exptime = 6, | |||
$rclass = '' ) |
Acquire an advisory lock on a key string, exclusive to the caller.
string | $key | |
int | $timeout | Lock wait timeout; 0 for non-blocking [optional] |
int | $exptime | Lock time-to-live in seconds; 1 day maximum [optional] |
string | $rclass | If this thread already holds the lock, and the lock was acquired using the same value for this parameter, then return true and use reference counting so that only the unlock() call from the outermost lock() caller actually releases the lock (note that only the outermost time-to-live is used) [optional] |
Reimplemented from BagOStuff.
Definition at line 160 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::makeGlobalKey | ( | $collection, | |
$components ) |
Make a cache key for the default keyspace and given components.
string | $collection | Key collection name component |
string|int | ...$components Additional, ordered, key components for entity IDs |
Reimplemented from BagOStuff.
Definition at line 270 of file ReplicatedBagOStuff.php.
References BagOStuff\genericKeyFromComponents().
ReplicatedBagOStuff::makeKey | ( | $collection, | |
$components ) |
Make a cache key for the global keyspace and given components.
string | $collection | Key collection name component |
string|int | ...$components Additional, ordered, key components for entity IDs |
Reimplemented from BagOStuff.
Definition at line 266 of file ReplicatedBagOStuff.php.
References BagOStuff\genericKeyFromComponents().
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protected |
Definition at line 262 of file ReplicatedBagOStuff.php.
References BagOStuff\$keyspace, and BagOStuff\genericKeyFromComponents().
ReplicatedBagOStuff::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 overridden in the callback. Nothing is stored nor deleted if the callback returns false.
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 |
InvalidArgumentException |
Reimplemented from BagOStuff.
Definition at line 136 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::set | ( | $key, | |
$value, | |||
$exptime = 0, | |||
$flags = 0 ) |
Set an item.
string | $key | |
mixed | $value | |
int | $exptime | Either an interval in seconds or a unix timestamp for expiry |
int | $flags | Bitfield of BagOStuff::WRITE_* constants |
Reimplemented from BagOStuff.
Definition at line 100 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::setMockTime | ( | & | $time | ) |
float | null | &$time | Mock UNIX timestamp |
Reimplemented from BagOStuff.
Definition at line 283 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::setMulti | ( | array | $valueByKey, |
$exptime = 0, | |||
$flags = 0 ) |
Set a batch of items.
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
mixed[] | $valueByKey | 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) |
Reimplemented from BagOStuff.
Definition at line 214 of file ReplicatedBagOStuff.php.
ReplicatedBagOStuff::unlock | ( | $key | ) |
Release an advisory lock on a key string.
string | $key |
Reimplemented from BagOStuff.
Definition at line 170 of file ReplicatedBagOStuff.php.