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Don't waste the last segment of each 4GB logical log file.

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The comments claimed that wasting the last segment made it easier to do
calculations with XLogRecPtrs, because you don't have problems representing
last-byte-position-plus-1 that way. In my experience, however, it only made
things more complicated, because the there was two ways to represent the
boundary at the beginning of a logical log file: logid = n+1 and xrecoff = 0,
or as xlogid = n and xrecoff = 4GB - XLOG_SEG_SIZE. Some functions were
picky about which representation was used.

Also, use a 64-bit segment number instead of the log/seg combination, to
point to a certain WAL segment. We assume that all platforms have a working
64-bit integer type nowadays.

This is an incompatible change in WAL format, so bumping WAL version number.
This commit is contained in:
Heikki Linnakangas
2012-06-24 18:06:38 +03:00
parent 47c7365e79
commit dfda6ebaec
12 changed files with 413 additions and 554 deletions
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11
src/include/access/xlog.h
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@ -267,12 +267,10 @@ extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata);
extern void XLogFlush(XLogRecPtr RecPtr);
extern bool XLogBackgroundFlush(void);
extern bool XLogNeedsFlush(XLogRecPtr RecPtr);
extern int XLogFileInit(uint32 log, uint32 seg,
bool *use_existent, bool use_lock);
extern int XLogFileOpen(uint32 log, uint32 seg);
extern int XLogFileInit(XLogSegNo segno, bool *use_existent, bool use_lock);
extern int XLogFileOpen(XLogSegNo segno);
extern void XLogGetLastRemoved(uint32 *log, uint32 *seg);
extern void XLogGetLastRemoved(XLogSegNo *segno);
extern void XLogSetAsyncXactLSN(XLogRecPtr record);
extern void RestoreBkpBlocks(XLogRecPtr lsn, XLogRecord *record, bool cleanup);
@ -280,7 +278,7 @@ extern void RestoreBkpBlocks(XLogRecPtr lsn, XLogRecord *record, bool cleanup);
extern void xlog_redo(XLogRecPtr lsn, XLogRecord *record);
extern void xlog_desc(StringInfo buf, uint8 xl_info, char *rec);
extern void issue_xlog_fsync(int fd, uint32 log, uint32 seg);
extern void issue_xlog_fsync(int fd, XLogSegNo segno);
extern bool RecoveryInProgress(void);
extern bool HotStandbyActive(void);
@ -294,6 +292,7 @@ extern bool RecoveryIsPaused(void);
extern void SetRecoveryPause(bool recoveryPause);
extern TimestampTz GetLatestXTime(void);
extern TimestampTz GetCurrentChunkReplayStartTime(void);
extern char *XLogFileNameP(TimeLineID tli, XLogSegNo segno);
extern void UpdateControlFile(void);
extern uint64 GetSystemIdentifier(void);