greenplumn CMDCache 代码
文件路径：/src/backend/gporca/libgpopt/include/gpopt/mdcache/CMDCache.h
/---------------------------------------------------------------------------
/ Greenplum Database
/ Copyright (C) 2011 EMC Corp.
/
/ @filename:
/ CMDCache.h
/
/ @doc:
/ Metadata cache.
/---------------------------------------------------------------------------
#ifndef GPOPT_CMDCache_H
#define GPOPT_CMDCache_H
#include "gpos/base.h"
#include "gpos/memory/CCache.h"
#include "gpos/memory/CCacheFactory.h"
#include "gpopt/mdcache/CMDAccessor.h"
#include "gpopt/mdcache/CMDKey.h"
namespace gpopt
{
using namespace gpos;
using namespace gpmd;
/---------------------------------------------------------------------------
/ @class:
/ CMDCache
/
/ @doc:
/ A wrapper for a generic cache to hide the details of metadata cache
/ creation and encapsulate a singleton cache object
/
/---------------------------------------------------------------------------
class CMDCache
{
private:
/ pointer to the underlying cache
static CMDAccessor::MDCache *m_pcache;
/ the maximum size of the cache
static ULLONG m_ullCacheQuota;
/ private ctor
CMDCache() = default;
/ private dtor
~CMDCache() = default;
public:
CMDCache(const CMDCache &) = delete;
/ initialize underlying cache
static void Init();
/ has cache been initialized?
static BOOL
FInitialized()
{
return (nullptr != m_pcache);
}
/ destroy global instance
static void Shutdown();
/ set the maximum size of the cache
static void SetCacheQuota(ULLONG ullCacheQuota);
/ get the maximum size of the cache
static ULLONG ULLGetCacheQuota();
/ get the number of times we evicted entries from this cache
static ULLONG ULLGetCacheEvictionCounter();
/ reset global instance
static void Reset();
/ global accessor
static CMDAccessor::MDCache *
Pcache()
{
return m_pcache;
}
}; / class CMDCache
} / namespace gpopt
#endif / !GPOPT_CMDCache_H
/ EOF