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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 CacheInterfaceBackend ()
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 CacheInterface* net_instaweb::CacheStats::Backend ( ) [inline, virtual]

If this cache is merely a wrapper around a backend that actually does all the work, returns that backend cache object. Otherwise just returns 'this'. Used for testing.

Reimplemented from net_instaweb::CacheInterface.

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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