75 lines
3.2 KiB
Markdown
75 lines
3.2 KiB
Markdown
# wikimedia/objectcache
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## Statistics
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Sent to StatsD under MediaWiki's namespace.
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### WANObjectCache
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The default WANObjectCache provided by MediaWikiServices disables these
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statistics in entry points where MW_ENTRY_POINT is 'cli'.
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#### `wanobjectcache.{kClass}.{cache_action_and_result}`
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Upon cache access via `WANObjectCache::getWithSetCallback()`, this measures the total time spent
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in this method from start to end for all cases, except process-cache hits.
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See also `wanobjectcache.{kClass}.regen_walltime`, which, during misses/renews, measures just the
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portion of time spent in the callback to regenerate the value.
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* Type: Measure (in milliseconds).
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* Variable `kClass`: The first part of your cache key.
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* Variable `result`: One of:
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* `"hit.good"`: A non-expired value was returned (and call did not get chosen
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for pre-emptive refresh).
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* `"hit.refresh"`: A non-expired value was returned (and call was chosen for
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a pre-emptive refresh, and an async refresh was scheduled).
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* `"hit.volatile"`: A value was found that was generated and stored less than 0.1s ago,
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and returned as-is despite appearing to also be expired already. This amount of time is
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considered negligible in terms of clock accuracy, and by random chance we usually decide
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to treat these as a cache hit (see `RECENT_SET_HIGH_MS`).
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* `"hit.stale"`: An expired value was found, but we are within the allowed stale period
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specified by a `lockTSE` option, and the current request did not get the regeneration lock.
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The stale value is returned as-is.
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* `"miss.compute"`: A new value was computed by the callback and returned.
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No non-expired value was found, and if this key needed a regeneration lock, we got the lock.
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* `"miss.busy"`: A busy value was produced by a `busyValue` callback and returned.
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No non-expired value was found, and we tried to use a regeneration lock (per the `busyValue`
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option), but the current request did not get the lock.
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* `"renew.compute"`: Artificial demand from an async refresh, led to a new value being
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computed by the callback. These are like `"miss.compute"`, but in response to `"hit.refresh"`.
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* `"renew.busy"`: Artificial demand from an async refresh failed to produce a value.
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The key used the `busyValue` option, and could not get a regeneration lock.
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#### `wanobjectcache.{kClass}.regen_walltime`
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Upon cache update due to a cache miss or async refresh, this measures the time spent in
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the regeneration callback when computing a new value.
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* Type: Measure (in milliseconds).
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* Variable `kClass`: The first part of your cache key.
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#### `wanobjectcache.{kClass}.ck_touch.{result}`
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Call counter from `WANObjectCache::touchCheckKey()`.
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* Type: Counter.
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* Variable `kClass`: The first part of your cache key.
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* Variable `result`: One of `"ok"` or `"error"`.
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#### `wanobjectcache.{kClass}.ck_reset.{result}`
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Call counter from `WANObjectCache::resetCheckKey()`.
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* Type: Counter.
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* Variable `kClass`: The first part of your cache key.
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* Variable `result`: One of `"ok"` or `"error"`.
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#### `wanobjectcache.{kClass}.delete.{result}`
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Call counter from `WANObjectCache::delete()`.
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* Type: Counter.
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* Variable `kClass`: The first part of your cache key.
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* Variable `result`: One of `"ok"` or `"error"`.
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