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354049c709
to write out data that we are about to tell the filesystem to drop. smgr_internal_unlink already had a DropRelFileNodeBuffers call to get rid of dead buffers without a write after it's no longer possible to roll back the deleting transaction. Adding a similar call in smgrtruncate simplifies callers and makes the overall division of labor clearer. This patch removes the former behavior that VACUUM would write all dirty buffers of a relation unconditionally.
165 lines
4.6 KiB
C
165 lines
4.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* bufmgr.h
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* POSTGRES buffer manager definitions.
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*
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*
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/storage/bufmgr.h,v 1.93 2005/03/20 22:00:54 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef BUFMGR_H
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#define BUFMGR_H
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#include "access/xlogdefs.h"
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#include "storage/buf.h"
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#include "storage/lock.h"
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#include "storage/relfilenode.h"
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#include "utils/rel.h"
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typedef void *Block;
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/* in globals.c ... this duplicates miscadmin.h */
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extern DLLIMPORT int NBuffers;
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/* in bufmgr.c */
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extern bool zero_damaged_pages;
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extern double bgwriter_lru_percent;
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extern double bgwriter_all_percent;
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extern int bgwriter_lru_maxpages;
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extern int bgwriter_all_maxpages;
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/* in buf_init.c */
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extern DLLIMPORT Block *BufferBlockPointers;
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extern DLLIMPORT int32 *PrivateRefCount;
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/* in localbuf.c */
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extern DLLIMPORT int NLocBuffer;
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extern DLLIMPORT Block *LocalBufferBlockPointers;
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extern DLLIMPORT int32 *LocalRefCount;
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/* special block number for ReadBuffer() */
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#define P_NEW InvalidBlockNumber /* grow the file to get a new page */
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/*
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* Buffer content lock modes (mode argument for LockBuffer())
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*/
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#define BUFFER_LOCK_UNLOCK 0
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#define BUFFER_LOCK_SHARE 1
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#define BUFFER_LOCK_EXCLUSIVE 2
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/*
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* These routines are beaten on quite heavily, hence the macroization.
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*/
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/*
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* BufferIsValid
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* True iff the given buffer number is valid (either as a shared
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* or local buffer).
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*
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* This is not quite the inverse of the BufferIsInvalid() macro, since this
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* adds sanity rangechecks on the buffer number.
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*
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* Note: For a long time this was defined the same as BufferIsPinned,
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* that is it would say False if you didn't hold a pin on the buffer.
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* I believe this was bogus and served only to mask logic errors.
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* Code should always know whether it has a buffer reference,
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* independently of the pin state.
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*/
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#define BufferIsValid(bufnum) \
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( \
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(bufnum) != InvalidBuffer && \
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(bufnum) >= -NLocBuffer && \
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(bufnum) <= NBuffers \
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)
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/*
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* BufferIsPinned
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* True iff the buffer is pinned (also checks for valid buffer number).
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*
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* NOTE: what we check here is that *this* backend holds a pin on
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* the buffer. We do not care whether some other backend does.
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*/
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#define BufferIsPinned(bufnum) \
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( \
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!BufferIsValid(bufnum) ? \
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false \
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: \
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BufferIsLocal(bufnum) ? \
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(LocalRefCount[-(bufnum) - 1] > 0) \
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: \
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(PrivateRefCount[(bufnum) - 1] > 0) \
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)
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/*
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* BufferGetBlock
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* Returns a reference to a disk page image associated with a buffer.
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*
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* Note:
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* Assumes buffer is valid.
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*/
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#define BufferGetBlock(buffer) \
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( \
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AssertMacro(BufferIsValid(buffer)), \
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BufferIsLocal(buffer) ? \
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LocalBufferBlockPointers[-(buffer) - 1] \
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: \
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BufferBlockPointers[(buffer) - 1] \
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)
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/*
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* prototypes for functions in bufmgr.c
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*/
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extern Buffer ReadBuffer(Relation reln, BlockNumber blockNum);
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extern void ReleaseBuffer(Buffer buffer);
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extern void IncrBufferRefCount(Buffer buffer);
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extern void WriteBuffer(Buffer buffer);
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extern void WriteNoReleaseBuffer(Buffer buffer);
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extern Buffer ReleaseAndReadBuffer(Buffer buffer, Relation relation,
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BlockNumber blockNum);
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extern void InitBufferPool(void);
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extern void InitBufferPoolAccess(void);
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extern char *ShowBufferUsage(void);
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extern void ResetBufferUsage(void);
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extern void AtEOXact_Buffers(bool isCommit);
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extern void AtProcExit_Buffers(void);
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extern void PrintBufferLeakWarning(Buffer buffer);
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extern void FlushBufferPool(void);
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extern BlockNumber BufferGetBlockNumber(Buffer buffer);
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extern BlockNumber RelationGetNumberOfBlocks(Relation relation);
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extern void RelationTruncate(Relation rel, BlockNumber nblocks);
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extern void FlushRelationBuffers(Relation rel);
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extern void DropRelFileNodeBuffers(RelFileNode rnode, bool istemp,
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BlockNumber firstDelBlock);
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extern void DropBuffers(Oid dbid);
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#ifdef NOT_USED
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extern void PrintPinnedBufs(void);
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#endif
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extern int BufferShmemSize(void);
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extern RelFileNode BufferGetFileNode(Buffer buffer);
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extern void SetBufferCommitInfoNeedsSave(Buffer buffer);
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extern void UnlockBuffers(void);
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extern void LockBuffer(Buffer buffer, int mode);
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extern bool ConditionalLockBuffer(Buffer buffer);
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extern void LockBufferForCleanup(Buffer buffer);
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extern void AbortBufferIO(void);
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extern void BufmgrCommit(void);
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extern void BufferSync(void);
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extern void BgBufferSync(void);
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extern void AtProcExit_LocalBuffers(void);
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/* in freelist.c */
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extern void StrategyHintVacuum(bool vacuum_active);
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#endif
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