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PopularityRefreshingWANObjectCache Class Reference
Inheritance diagram for PopularityRefreshingWANObjectCache:
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Protected Member Functions

 worthRefreshPopular ( $asOf, $ageNew, $timeTillRefresh, $now)
 Check if a key is due for randomized regeneration due to its popularity.
 
- Protected Member Functions inherited from WANObjectCache
 determineKeyClass ( $key)
 
 doGetWithSetCallback ( $key, $ttl, $callback, array $opts, &$asOf=null)
 Do the actual I/O for getWithSetCallback() when needed.
 
 getCurrentTime ()
 
 getInterimValue ( $key, $versioned, $minTime, &$asOf)
 
 getProcessCache ( $group)
 
 isAliveOrInGracePeriod ( $curTTL, $graceTTL)
 Check if a key is fresh or in the grace window and thus due for randomized reuse.
 
 isValid ( $value, $versioned, $asOf, $minTime)
 Check whether $value is appropriately versioned and not older than $minTime (if set)
 
 makePurgeValue ( $timestamp, $holdoff)
 
 parsePurgeValue ( $value)
 
 relayDelete ( $key)
 Do the actual async bus delete of a key.
 
 relayPurge ( $key, $ttl, $holdoff)
 Do the actual async bus purge of a key.
 
 setInterimValue ( $key, $wrapped, $tempTTL)
 
 unwrap ( $wrapped, $now)
 Do not use this method outside WANObjectCache.
 
 worthRefreshExpiring ( $curTTL, $lowTTL)
 Check if a key is nearing expiration and thus due for randomized regeneration.
 
 wrap ( $value, $ttl, $now)
 Do not use this method outside WANObjectCache.
 

Additional Inherited Members

- Public Member Functions inherited from WANObjectCache
 __construct (array $params)
 
 adaptiveTTL ( $mtime, $maxTTL, $minTTL=30, $factor=0.2)
 Get a TTL that is higher for objects that have not changed recently.
 
 clearLastError ()
 Clear the "last error" registry.
 
 clearProcessCache ()
 Clear the in-process caches; useful for testing.
 
 delete ( $key, $ttl=self::HOLDOFF_TTL)
 Purge a key from all datacenters.
 
 get ( $key, &$curTTL=null, array $checkKeys=[], &$asOf=null)
 Fetch the value of a key from cache.
 
 getCheckKeyTime ( $key)
 Fetch the value of a timestamp "check" key.
 
 getLastError ()
 Get the "last error" registered; clearLastError() should be called manually.
 
 getMulti (array $keys, &$curTTLs=[], array $checkKeys=[], array &$asOfs=[])
 Fetch the value of several keys from cache.
 
 getMultiCheckKeyTime (array $keys)
 Fetch the values of each timestamp "check" key.
 
 getMultiWithSetCallback (ArrayIterator $keyedIds, $ttl, callable $callback, array $opts=[])
 Method to fetch multiple cache keys at once with regeneration.
 
 getMultiWithUnionSetCallback (ArrayIterator $keyedIds, $ttl, callable $callback, array $opts=[])
 Method to fetch/regenerate multiple cache keys at once.
 
 getQoS ( $flag)
 
 getWarmupKeyMisses ()
 
 getWithSetCallback ( $key, $ttl, $callback, array $opts=[])
 Method to fetch/regenerate cache keys.
 
 makeGlobalKey ( $class, $component=null)
 
 makeKey ( $class, $component=null)
 
 makeMultiKeys (array $entities, callable $keyFunc)
 
 reap ( $key, $purgeTimestamp, &$isStale=false)
 Set a key to soon expire in the local cluster if it pre-dates $purgeTimestamp.
 
 reapCheckKey ( $key, $purgeTimestamp, &$isStale=false)
 Set a "check" key to soon expire in the local cluster if it pre-dates $purgeTimestamp.
 
 resetCheckKey ( $key)
 Delete a "check" key from all datacenters, invalidating keys that use it.
 
 set ( $key, $value, $ttl=0, array $opts=[])
 Set the value of a key in cache.
 
 setLogger (LoggerInterface $logger)
 
 setMockTime (&$time)
 
 touchCheckKey ( $key, $holdoff=self::HOLDOFF_TTL)
 Purge a "check" key from all datacenters, invalidating keys that use it.
 
 useInterimHoldOffCaching ( $enabled)
 Enable or disable the use of brief caching for tombstoned keys.
 
- Static Public Member Functions inherited from WANObjectCache
static newEmpty ()
 Get an instance that wraps EmptyBagOStuff.
 
- Public Attributes inherited from WANObjectCache
const AGE_NEW = 60
 Never consider performing "popularity" refreshes until a key reaches this age.
 
const CHECK_KEY_TTL = self::TTL_YEAR
 Seconds to keep dependency purge keys around.
 
const DEFAULT_PURGE_CHANNEL = 'wancache-purge'
 
const ERR_NO_RESPONSE = 1
 
const ERR_NONE = 0
 
const ERR_RELAY = 4
 
const ERR_UNEXPECTED = 3
 
const ERR_UNREACHABLE = 2
 
const FLD_FLAGS = 4
 
const FLD_HOLDOFF = 5
 
const FLD_TIME = 3
 
const FLD_TTL = 2
 
const FLD_VALUE = 1
 
const FLD_VERSION = 0
 
const GRACE_TTL_NONE = 0
 Idiom for set()/getWithSetCallback() for "no post-expired grace period".
 
const HIT_RATE_HIGH = 1
 Hits/second for a refresh to be expected within the "popularity" window.
 
const HOLDOFF_NONE = 0
 Idiom for delete() for "no hold-off".
 
const HOLDOFF_TTL = 11
 Seconds to tombstone keys on delete()
 
const HOT_TTR = 900
 The time length of the "popularity" refresh window for hot keys.
 
const INTERIM_KEY_PREFIX = 'WANCache:i:'
 
const INTERIM_KEY_TTL = 1
 Seconds to keep interim value keys for tombstoned keys around.
 
const LOCK_TTL = 10
 Seconds to keep lock keys around.
 
const LOW_TTL = 30
 Default remaining TTL at which to consider pre-emptive regeneration.
 
const MAX_COMMIT_DELAY = 3
 Max time expected to pass between delete() and DB commit finishing.
 
const MAX_READ_LAG = 7
 Max replication+snapshot lag before applying TTL_LAGGED or disallowing set()
 
const MIN_TIMESTAMP_NONE = 0.0
 Idiom for getWithSetCallback() for "no minimum required as-of timestamp".
 
const MUTEX_KEY_PREFIX = 'WANCache:m:'
 
const PC_PRIMARY = 'primary:1000'
 
const PURGE_VAL_PREFIX = 'PURGED:'
 
const RAMPUP_TTL = 30
 Seconds to ramp up to the "popularity" refresh chance after a key is no longer new.
 
const STALE_TTL_NONE = 0
 Idiom for set()/getWithSetCallback() for "do not augment the storage medium TTL".
 
const TIME_KEY_PREFIX = 'WANCache:t:'
 
const TINY_NEGATIVE = -0.000001
 Tiny negative float to use when CTL comes up >= 0 due to clock skew.
 
const TSE_NONE = -1
 Idiom for getWithSetCallback() callbacks to 'lockTSE' logic.
 
const TTL_LAGGED = 30
 Max TTL to store keys when a data sourced is lagged.
 
const TTL_UNCACHEABLE = -1
 Idiom for getWithSetCallback() callbacks to avoid calling set()
 
const VALUE_KEY_PREFIX = 'WANCache:v:'
 
const VERSION = 1
 Cache format version number.
 
const VFLD_DATA = 'WOC:d'
 
const VFLD_VERSION = 'WOC:v'
 
- Public Attributes inherited from IExpiringStore
const ATTR_EMULATION = 1
 
const ATTR_SYNCWRITES = 2
 
const QOS_EMULATION_SQL = 1
 
const QOS_SYNCWRITES_BE = 2
 
const QOS_SYNCWRITES_NONE = 1
 
const QOS_SYNCWRITES_QC = 3
 
const QOS_SYNCWRITES_SS = 4
 
const QOS_UNKNOWN = INF
 
const TTL_DAY = 86400
 
const TTL_HOUR = 3600
 
const TTL_INDEFINITE = 0
 
const TTL_MINUTE = 60
 
const TTL_MONTH = 2592000
 
const TTL_PROC_LONG = 30
 
const TTL_PROC_SHORT = 3
 
const TTL_SECOND = 1
 
const TTL_WEEK = 604800
 
const TTL_YEAR = 31536000
 
- Static Protected Member Functions inherited from WANObjectCache
static prefixCacheKeys (array $keys, $prefix)
 
- Protected Attributes inherited from WANObjectCache
callable null $asyncHandler
 Function that takes a WAN cache callback and runs it later.
 
BagOStuff $cache
 The local datacenter cache.
 
string $cluster
 Cache cluster name for mcrouter use.
 
int $lastRelayError = self::ERR_NONE
 ERR_* constant for the "last error" registry.
 
LoggerInterface $logger
 
 $mcrouterAware
 @bar bool Whether to use mcrouter key prefixing for routing
 
HashBagOStuff[] $processCaches = []
 Map of group PHP instance caches.
 
string $purgeChannel
 Purge channel name.
 
EventRelayer $purgeRelayer
 Bus that handles purge broadcasts.
 
string $region
 Physical region for mcrouter use.
 
StatsdDataFactoryInterface $stats
 
bool $useInterimHoldOffCaching = true
 Whether to use "interim" caching while keys are tombstoned.
 

Detailed Description

Definition at line 1707 of file WANObjectCacheTest.php.

Member Function Documentation

◆ worthRefreshPopular()

PopularityRefreshingWANObjectCache::worthRefreshPopular (   $asOf,
  $ageNew,
  $timeTillRefresh,
  $now 
)
protected

Check if a key is due for randomized regeneration due to its popularity.

This is used so that popular keys can preemptively refresh themselves for higher consistency (especially in the case of purge loss/delay). Unpopular keys can remain in cache with their high nominal TTL. This means popular keys keep good consistency, whether the data changes frequently or not, and long-tail keys get to stay in cache and get hits too. Similar to worthRefreshExpiring(), randomization is used.

Parameters
float$asOfUNIX timestamp of the value
int$ageNewAge of key when this might recommend refreshing (seconds)
int$timeTillRefreshAge of key when it should be refreshed if popular (seconds)
float$nowThe current UNIX timestamp
Returns
bool

Reimplemented from WANObjectCache.

Definition at line 1708 of file WANObjectCacheTest.php.

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