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firebird-mirror/src/jrd/GarbageCollector.h
hvlad f7e248ca63 Improvement CORE-4935 : Increase performance of backout of dead record version (or undo of just created primary record version) when backversions chain is too long
Improvement CORE-4936 : Reduce internal contention in background garbage collector
Other small improvements: 
- garbage collector\sweep now skip record header if transaction is below OIT - it allows to reduce number of page fetches
- missed points to gather RECORD_FRAGMENT_READS and RECORD_BACKVERSION_READS statistics
2015-09-16 21:16:13 +00:00

127 lines
2.9 KiB
C++

/*
* The contents of this file are subject to the Initial
* Developer's Public License Version 1.0 (the "License");
* you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
* http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
*
* Software distributed under the License is distributed AS IS,
* WITHOUT WARRANTY OF ANY KIND, either express or implied.
* See the License for the specific language governing rights
* and limitations under the License.
*
* The Original Code was created by Vlad Khorsun
* for the Firebird Open Source RDBMS project.
*
* Copyright (c) 2011 Vlad Khorsun <hvlad@users.sourceforge.net>
* and all contributors signed below.
*
* All Rights Reserved.
* Contributor(s): ______________________________________.
*/
#ifndef JRD_GARBAGE_COLLECTOR_H
#define JRD_GARBAGE_COLLECTOR_H
#include "firebird.h"
#include "../common/classes/array.h"
#include "../common/classes/GenericMap.h"
#include "../common/classes/SyncObject.h"
#include "../jrd/sbm.h"
namespace Jrd {
class Database;
class Savepoint;
class GarbageCollector
{
public:
GarbageCollector(MemoryPool& p, Database* dbb)
: m_pool(p), m_relations(m_pool), m_nextRelID(0)
{}
~GarbageCollector();
TraNumber addPage(const USHORT relID, const ULONG pageno, const TraNumber tranid);
PageBitmap* getPages(const TraNumber oldest_snapshot, USHORT &relID);
void removeRelation(const USHORT relID);
void sweptRelation(const TraNumber oldest_snapshot, const USHORT relID);
private:
struct PageTran
{
PageTran() :
pageno(0),
tranid(0)
{}
PageTran(const ULONG _pageno, const TraNumber _tranid) :
pageno(_pageno),
tranid(_tranid)
{}
ULONG pageno;
TraNumber tranid;
static const ULONG& generate(const void*, const PageTran& item)
{
return item.pageno;
}
};
typedef Firebird::BePlusTree<PageTran, ULONG, MemoryPool, PageTran> PageTranMap;
class RelationData
{
public:
explicit RelationData(MemoryPool& p, USHORT relID)
: m_pool(p), m_pages(p), m_relID(relID)
{}
~RelationData()
{
clear();
}
TraNumber addPage(const ULONG pageno, const TraNumber tranid);
TraNumber findPage(const ULONG pageno, const TraNumber tranid);
void swept(const TraNumber oldest_snapshot, PageBitmap** bm = NULL);
USHORT getRelID() const
{
return m_relID;
}
static inline const USHORT generate(const RelationData* item)
{
return item->m_relID;
}
void clear();
Firebird::MemoryPool& m_pool;
Firebird::SyncObject m_sync;
PageTranMap m_pages;
USHORT m_relID;
};
typedef Firebird::SortedArray<
RelationData*,
Firebird::EmptyStorage<RelationData*>,
USHORT,
RelationData> RelGarbageArray;
RelationData* getRelData(Firebird::Sync& sync, const USHORT relID, bool allowCreate);
Firebird::MemoryPool& m_pool;
Firebird::SyncObject m_sync;
RelGarbageArray m_relations;
USHORT m_nextRelID;
};
} // namespace Jrd
#endif // JRD_GARBAGE_COLLECTOR_H