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01ec25631f
No more indirect blocks. The blocks form a linked list instead. This saves some memory, because we don't need to have a buffer in memory to hold the indirect block (or blocks). To reflect that, TAPE_BUFFER_OVERHEAD is reduced from 3 to 1 buffer, which allows using more memory for building the initial runs. Reviewed by Peter Geoghegan and Robert Haas. Discussion: https://www.postgresql.org/message-id/34678beb-938e-646e-db9f-a7def5c44ada%40iki.fi
46 lines
1.6 KiB
C
46 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) 1996-2016, 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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* src/include/utils/logtape.h
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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 LogicalTapeRewindForRead(LogicalTapeSet *lts, int tapenum,
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size_t buffer_size);
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extern void LogicalTapeRewindForWrite(LogicalTapeSet *lts, int tapenum);
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extern void LogicalTapeFreeze(LogicalTapeSet *lts, int tapenum);
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extern size_t LogicalTapeBackspace(LogicalTapeSet *lts, int tapenum,
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size_t size);
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extern void 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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