diff options
Diffstat (limited to 'src/backend/access/transam/xlog.c')
| -rw-r--r-- | src/backend/access/transam/xlog.c | 111 |
1 files changed, 45 insertions, 66 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index c9e3a7af7b3..8d43660353f 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -458,15 +458,6 @@ typedef struct XLogCtlInsert } XLogCtlInsert; /* - * Shared state data for XLogWrite/XLogFlush. - */ -typedef struct XLogCtlWrite -{ - int curridx; /* cache index of next block to write */ - pg_time_t lastSegSwitchTime; /* time of last xlog segment switch */ -} XLogCtlWrite; - -/* * Total shared-memory state for XLOG. */ typedef struct XLogCtlData @@ -482,12 +473,12 @@ typedef struct XLogCtlData XLogSegNo lastRemovedSegNo; /* latest removed/recycled XLOG * segment */ - /* Fake LSN counter, for unlogged relations. Protected by ulsn_lck */ + /* Fake LSN counter, for unlogged relations. Protected by ulsn_lck. */ XLogRecPtr unloggedLSN; slock_t ulsn_lck; - /* Protected by WALWriteLock: */ - XLogCtlWrite Write; + /* Time of last xlog segment switch. Protected by WALWriteLock. */ + pg_time_t lastSegSwitchTime; /* * Protected by info_lck and WALWriteLock (you must hold either lock to @@ -496,15 +487,15 @@ typedef struct XLogCtlData XLogwrtResult LogwrtResult; /* - * Latest initialized block index in cache. + * Latest initialized page in the cache (last byte position + 1). * - * To change curridx and the identity of a buffer, you need to hold - * WALBufMappingLock. To change the identity of a buffer that's still + * To change the identity of a buffer (and InitializedUpTo), you need to + * hold WALBufMappingLock. To change the identity of a buffer that's still * dirty, the old page needs to be written out first, and for that you * need WALWriteLock, and you need to ensure that there are no in-progress * insertions to the page by calling WaitXLogInsertionsToFinish(). */ - int curridx; + XLogRecPtr InitializedUpTo; /* * These values do not change after startup, although the pointed-to pages @@ -618,16 +609,10 @@ static ControlFileData *ControlFile = NULL; /* * XLogRecPtrToBufIdx returns the index of the WAL buffer that holds, or * would hold if it was in cache, the page containing 'recptr'. - * - * XLogRecEndPtrToBufIdx is the same, but a pointer to the first byte of a - * page is taken to mean the previous page. */ #define XLogRecPtrToBufIdx(recptr) \ (((recptr) / XLOG_BLCKSZ) % (XLogCtl->XLogCacheBlck + 1)) -#define XLogRecEndPtrToBufIdx(recptr) \ - ((((recptr) - 1) / XLOG_BLCKSZ) % (XLogCtl->XLogCacheBlck + 1)) - /* * These are the number of bytes in a WAL page and segment usable for WAL data. */ @@ -2409,9 +2394,9 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic) * Now that we have the lock, check if someone initialized the page * already. */ - while (upto >= XLogCtl->xlblocks[XLogCtl->curridx] || opportunistic) + while (upto >= XLogCtl->InitializedUpTo || opportunistic) { - nextidx = NextBufIdx(XLogCtl->curridx); + nextidx = XLogRecPtrToBufIdx(XLogCtl->InitializedUpTo); /* * Get ending-offset of the buffer page we need to replace (this may @@ -2484,11 +2469,9 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic) * Now the next buffer slot is free and we can set it up to be the next * output page. */ - NewPageBeginPtr = XLogCtl->xlblocks[XLogCtl->curridx]; + NewPageBeginPtr = XLogCtl->InitializedUpTo; NewPageEndPtr = NewPageBeginPtr + XLOG_BLCKSZ; - Assert(NewPageEndPtr % XLOG_BLCKSZ == 0); - Assert(XLogRecEndPtrToBufIdx(NewPageEndPtr) == nextidx); Assert(XLogRecPtrToBufIdx(NewPageBeginPtr) == nextidx); NewPage = (XLogPageHeader) (XLogCtl->pages + nextidx * (Size) XLOG_BLCKSZ); @@ -2547,7 +2530,7 @@ AdvanceXLInsertBuffer(XLogRecPtr upto, bool opportunistic) *((volatile XLogRecPtr *) &XLogCtl->xlblocks[nextidx]) = NewPageEndPtr; - XLogCtl->curridx = nextidx; + XLogCtl->InitializedUpTo = NewPageEndPtr; npages++; } @@ -2598,7 +2581,6 @@ XLogCheckpointNeeded(XLogSegNo new_segno) static void XLogWrite(XLogwrtRqst WriteRqst, bool flexible) { - XLogCtlWrite *Write = &XLogCtl->Write; bool ispartialpage; bool last_iteration; bool finishing_seg; @@ -2631,12 +2613,10 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible) /* * Within the loop, curridx is the cache block index of the page to - * consider writing. We advance Write->curridx only after successfully - * writing pages. (Right now, this refinement is useless since we are - * going to PANIC if any error occurs anyway; but someday it may come in - * useful.) + * consider writing. Begin at the buffer containing the next unwritten + * page, or last partially written page. */ - curridx = Write->curridx; + curridx = XLogRecPtrToBufIdx(LogwrtResult.Write); while (LogwrtResult.Write < WriteRqst.Write) { @@ -2747,7 +2727,6 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible) /* Update state for write */ openLogOff += nbytes; - Write->curridx = ispartialpage ? curridx : NextBufIdx(curridx); npages = 0; /* @@ -2775,7 +2754,7 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible) if (XLogArchivingActive()) XLogArchiveNotifySeg(openLogSegNo); - Write->lastSegSwitchTime = (pg_time_t) time(NULL); + XLogCtl->lastSegSwitchTime = (pg_time_t) time(NULL); /* * Request a checkpoint if we've consumed too much xlog since @@ -2807,7 +2786,6 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible) } Assert(npages == 0); - Assert(curridx == Write->curridx); /* * If asked to flush, do so @@ -6021,12 +5999,10 @@ StartupXLOG(void) XLogSegNo endLogSegNo; TimeLineID PrevTimeLineID; XLogRecord *record; - uint32 freespace; TransactionId oldestActiveXID; bool backupEndRequired = false; bool backupFromStandby = false; DBState dbstate_at_startup; - int firstIdx; XLogReaderState *xlogreader; XLogPageReadPrivate private; bool fast_promoted = false; @@ -7034,48 +7010,51 @@ StartupXLOG(void) openLogOff = 0; Insert = &XLogCtl->Insert; Insert->PrevBytePos = XLogRecPtrToBytePos(LastRec); - - firstIdx = XLogRecEndPtrToBufIdx(EndOfLog); - XLogCtl->curridx = firstIdx; - - XLogCtl->xlblocks[firstIdx] = ((EndOfLog - 1) / XLOG_BLCKSZ + 1) * XLOG_BLCKSZ; + Insert->CurrBytePos = XLogRecPtrToBytePos(EndOfLog); /* * Tricky point here: readBuf contains the *last* block that the LastRec * record spans, not the one it starts in. The last block is indeed the * one we want to use. */ - Assert(readOff == (XLogCtl->xlblocks[firstIdx] - XLOG_BLCKSZ) % XLogSegSize); - memcpy((char *) &XLogCtl->pages[firstIdx * XLOG_BLCKSZ], xlogreader->readBuf, XLOG_BLCKSZ); - Insert->CurrBytePos = XLogRecPtrToBytePos(EndOfLog); + if (EndOfLog % XLOG_BLCKSZ != 0) + { + char *page; + int len; + int firstIdx; + XLogRecPtr pageBeginPtr; - LogwrtResult.Write = LogwrtResult.Flush = EndOfLog; + pageBeginPtr = EndOfLog - (EndOfLog % XLOG_BLCKSZ); + Assert(readOff == pageBeginPtr % XLogSegSize); - XLogCtl->LogwrtResult = LogwrtResult; + firstIdx = XLogRecPtrToBufIdx(EndOfLog); - XLogCtl->LogwrtRqst.Write = EndOfLog; - XLogCtl->LogwrtRqst.Flush = EndOfLog; + /* Copy the valid part of the last block, and zero the rest */ + page = &XLogCtl->pages[firstIdx * XLOG_BLCKSZ]; + len = EndOfLog % XLOG_BLCKSZ; + memcpy(page, xlogreader->readBuf, len); + memset(page + len, 0, XLOG_BLCKSZ - len); - freespace = INSERT_FREESPACE(EndOfLog); - if (freespace > 0) - { - /* Make sure rest of page is zero */ - MemSet(&XLogCtl->pages[firstIdx * XLOG_BLCKSZ] + EndOfLog % XLOG_BLCKSZ, 0, freespace); - XLogCtl->Write.curridx = firstIdx; + XLogCtl->xlblocks[firstIdx] = pageBeginPtr + XLOG_BLCKSZ; + XLogCtl->InitializedUpTo = pageBeginPtr + XLOG_BLCKSZ; } else { /* - * Whenever LogwrtResult points to exactly the end of a page, - * Write.curridx must point to the *next* page (see XLogWrite()). - * - * Note: it might seem we should do AdvanceXLInsertBuffer() here, but - * this is sufficient. The first actual attempt to insert a log - * record will advance the insert state. + * There is no partial block to copy. Just set InitializedUpTo, + * and let the first attempt to insert a log record to initialize + * the next buffer. */ - XLogCtl->Write.curridx = NextBufIdx(firstIdx); + XLogCtl->InitializedUpTo = EndOfLog; } + LogwrtResult.Write = LogwrtResult.Flush = EndOfLog; + + XLogCtl->LogwrtResult = LogwrtResult; + + XLogCtl->LogwrtRqst.Write = EndOfLog; + XLogCtl->LogwrtRqst.Flush = EndOfLog; + /* Pre-scan prepared transactions to find out the range of XIDs present */ oldestActiveXID = PrescanPreparedTransactions(NULL, NULL); @@ -7199,7 +7178,7 @@ StartupXLOG(void) LWLockRelease(ControlFileLock); /* start the archive_timeout timer running */ - XLogCtl->Write.lastSegSwitchTime = (pg_time_t) time(NULL); + XLogCtl->lastSegSwitchTime = (pg_time_t) time(NULL); /* also initialize latestCompletedXid, to nextXid - 1 */ LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE); @@ -7710,7 +7689,7 @@ GetLastSegSwitchTime(void) /* Need WALWriteLock, but shared lock is sufficient */ LWLockAcquire(WALWriteLock, LW_SHARED); - result = XLogCtl->Write.lastSegSwitchTime; + result = XLogCtl->lastSegSwitchTime; LWLockRelease(WALWriteLock); return result; |