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8db05ba411
we are doing the final merge pass on-the-fly, and not writing the data back onto a 'tape', the number of free blocks in the tape set will become large, leading to a lot of time wasted in ltsReleaseBlock(). There is really no need to track the free blocks anymore in this state, so add a simple shutoff switch. Per report from Stefan Kaltenbrunner.
44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* logtape.h
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* Management of "logical tapes" within temporary files.
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*
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* See logtape.c for explanations.
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*
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* Portions Copyright (c) 1996-2006, 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/utils/logtape.h,v 1.15 2006/03/07 19:06:50 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef LOGTAPE_H
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#define LOGTAPE_H
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/* LogicalTapeSet is an opaque type whose details are not known outside logtape.c. */
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typedef struct LogicalTapeSet LogicalTapeSet;
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/*
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* prototypes for functions in logtape.c
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*/
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extern LogicalTapeSet *LogicalTapeSetCreate(int ntapes);
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extern void LogicalTapeSetClose(LogicalTapeSet *lts);
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extern void LogicalTapeSetForgetFreeSpace(LogicalTapeSet *lts);
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extern size_t LogicalTapeRead(LogicalTapeSet *lts, int tapenum,
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void *ptr, size_t size);
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extern void LogicalTapeWrite(LogicalTapeSet *lts, int tapenum,
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void *ptr, size_t size);
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extern void LogicalTapeRewind(LogicalTapeSet *lts, int tapenum, bool forWrite);
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extern void LogicalTapeFreeze(LogicalTapeSet *lts, int tapenum);
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extern bool LogicalTapeBackspace(LogicalTapeSet *lts, int tapenum,
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size_t size);
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extern bool LogicalTapeSeek(LogicalTapeSet *lts, int tapenum,
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long blocknum, int offset);
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extern void LogicalTapeTell(LogicalTapeSet *lts, int tapenum,
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long *blocknum, int *offset);
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extern long LogicalTapeSetBlocks(LogicalTapeSet *lts);
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#endif /* LOGTAPE_H */
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