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net_instaweb::CacheStats Class Reference

#include "cache_stats.h"

Inheritance diagram for net_instaweb::CacheStats:
net_instaweb::CacheInterface

List of all members.

Public Member Functions

 CacheStats (StringPiece prefix, CacheInterface *cache, Timer *timer, Statistics *statistics)
 Takes ownership of the cache.
virtual void Get (const GoogleString &key, Callback *callback)
virtual void MultiGet (MultiGetRequest *request)
virtual void Put (const GoogleString &key, SharedString *value)
virtual void Delete (const GoogleString &key)
virtual const char * Name () const
 The name of this CacheInterface -- used for logging and debugging.
virtual bool IsBlocking () const
virtual bool IsHealthy () const
virtual void ShutDown ()

Static Public Member Functions

static void InitStats (StringPiece prefix, Statistics *statistics)
 This must be called once for every unique cache prefix.

Friends

class StatsCallback

Detailed Description

Wrapper around a CacheInterface that adds statistics and histograms for hit-rate, latency, etc. As there can be multiple caches in a system (l1, l2, etc), the constructor takes a string prefix so they can be measured independently.


Member Function Documentation

virtual void net_instaweb::CacheStats::Get ( const GoogleString key,
Callback callback 
) [virtual]

Initiates a cache fetch, calling callback->ValidateCandidate() and then callback->Done(state) when done.

Note: implementations should normally invoke the callback via ValidateAndReportResult, which will combine ValidateCandidate() and Done() together properly.

Implements net_instaweb::CacheInterface.

virtual bool net_instaweb::CacheStats::IsBlocking ( ) const [inline, virtual]

Returns true if this cache is guaranteed to call its callbacks before returning from Get and MultiGet.

Implements net_instaweb::CacheInterface.

virtual bool net_instaweb::CacheStats::IsHealthy ( ) const [inline, virtual]

Returns true if the cache is in a healthy state. Memory and file-based caches can simply return 'true'. But for server-based caches, it is handy to be able to query to see whether it is in a good state. It should be safe to call this frequently -- the implementation shouldn't do much more than check a bool flag under mutex.

Implements net_instaweb::CacheInterface.

virtual void net_instaweb::CacheStats::MultiGet ( MultiGetRequest *  request) [virtual]

Gets multiple keys, calling multiple callbacks. Default implementation simply loops over all the keys and calls Get.

MultiGetRequest, declared above, is a vector of structs of keys and callbacks.

Ownership of the request is transferred to this function.

Reimplemented from net_instaweb::CacheInterface.

virtual void net_instaweb::CacheStats::Put ( const GoogleString key,
SharedString value 
) [virtual]

Puts a value into the cache. The value that is passed in is not modified, but the SharedString is passed by non-const pointer because its reference count is bumped.

Implements net_instaweb::CacheInterface.

virtual void net_instaweb::CacheStats::ShutDown ( ) [inline, virtual]

Stops all cache activity. Further Put/Delete calls will be dropped, and MultiGet/Get will call the callback with kNotFound immediately. Note there is no Enable(); once the cache is stopped it is stopped forever. This function is intended for use during process shutdown.

Implements net_instaweb::CacheInterface.


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