diff options
| -rw-r--r-- | src/backend/access/transam/xlog.c | 82 |
1 files changed, 61 insertions, 21 deletions
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index aaa8ef423c5..53044eb4f68 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -2904,12 +2904,15 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock) * srcTLI, srclog, srcseg: identify segment to be copied (could be from * a different timeline) * + * upto: how much of the source file to copy? (the rest is filled with zeros) + * * Currently this is only used during recovery, and so there are no locking * considerations. But we should be just as tense as XLogFileInit to avoid * emplacing a bogus file. */ static void -XLogFileCopy(XLogSegNo destsegno, TimeLineID srcTLI, XLogSegNo srcsegno) +XLogFileCopy(XLogSegNo destsegno, TimeLineID srcTLI, XLogSegNo srcsegno, + int upto) { char path[MAXPGPATH]; char tmppath[MAXPGPATH]; @@ -2948,16 +2951,31 @@ XLogFileCopy(XLogSegNo destsegno, TimeLineID srcTLI, XLogSegNo srcsegno) */ for (nbytes = 0; nbytes < XLogSegSize; nbytes += sizeof(buffer)) { - errno = 0; - if ((int) read(srcfd, buffer, sizeof(buffer)) != (int) sizeof(buffer)) + int nread; + + nread = upto - nbytes; + + /* + * The part that is not read from the source file is filled with zeros. + */ + if (nread < sizeof(buffer)) + memset(buffer, 0, sizeof(buffer)); + + if (nread > 0) { - if (errno != 0) - ereport(ERROR, - (errcode_for_file_access(), - errmsg("could not read file \"%s\": %m", path))); - else - ereport(ERROR, - (errmsg("not enough data in file \"%s\"", path))); + if (nread > sizeof(buffer)) + nread = sizeof(buffer); + errno = 0; + if (read(srcfd, buffer, nread) != nread) + { + if (errno != 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", path))); + else + ereport(ERROR, + (errmsg("not enough data in file \"%s\"", path))); + } } errno = 0; if ((int) write(fd, buffer, sizeof(buffer)) != (int) sizeof(buffer)) @@ -4960,10 +4978,15 @@ readRecoveryCommandFile(void) * Exit archive-recovery state */ static void -exitArchiveRecovery(TimeLineID endTLI, XLogSegNo endLogSegNo) +exitArchiveRecovery(TimeLineID endTLI, XLogRecPtr endOfLog) { char recoveryPath[MAXPGPATH]; char xlogfname[MAXFNAMELEN]; + XLogSegNo endLogSegNo; + XLogSegNo startLogSegNo; + + /* we always switch to a new timeline after archive recovery */ + Assert(endTLI != ThisTimeLineID); /* * We are no longer in archive recovery state. @@ -4986,18 +5009,29 @@ exitArchiveRecovery(TimeLineID endTLI, XLogSegNo endLogSegNo) } /* - * If we are establishing a new timeline, we have to copy data from the - * last WAL segment of the old timeline to create a starting WAL segment - * for the new timeline. + * Calculate the last segment on the old timeline, and the first segment + * on the new timeline. If the switch happens in the middle of a segment, + * they are the same, but if the switch happens exactly at a segment + * boundary, startLogSegNo will be endLogSegNo + 1. + */ + XLByteToPrevSeg(endOfLog, endLogSegNo); + XLByteToSeg(endOfLog, startLogSegNo); + + /* + * Initialize the starting WAL segment for the new timeline. If the switch + * happens in the middle of a segment, copy data from the last WAL segment + * of the old timeline up to the switch point, to the starting WAL segment + * on the new timeline. * * Notify the archiver that the last WAL segment of the old timeline is * ready to copy to archival storage if its .done file doesn't exist * (e.g., if it's the restored WAL file, it's expected to have .done file). * Otherwise, it is not archived for a while. */ - if (endTLI != ThisTimeLineID) + if (endLogSegNo == startLogSegNo) { - XLogFileCopy(endLogSegNo, endTLI, endLogSegNo); + XLogFileCopy(startLogSegNo, endTLI, endLogSegNo, + endOfLog % XLOG_SEG_SIZE); /* Create .ready file only when neither .ready nor .done files exist */ if (XLogArchivingActive()) @@ -5006,12 +5040,18 @@ exitArchiveRecovery(TimeLineID endTLI, XLogSegNo endLogSegNo) XLogArchiveCheckDone(xlogfname); } } + else + { + bool use_existent = true; + + XLogFileInit(startLogSegNo, &use_existent, true); + } /* * Let's just make real sure there are not .ready or .done flags posted * for the new segment. */ - XLogFileName(xlogfname, ThisTimeLineID, endLogSegNo); + XLogFileName(xlogfname, ThisTimeLineID, startLogSegNo); XLogArchiveCleanup(xlogfname); /* @@ -5599,7 +5639,7 @@ StartupXLOG(void) XLogRecPtr RecPtr, checkPointLoc, EndOfLog; - XLogSegNo endLogSegNo; + XLogSegNo startLogSegNo; TimeLineID PrevTimeLineID; XLogRecord *record; TransactionId oldestActiveXID; @@ -6586,7 +6626,7 @@ StartupXLOG(void) */ record = ReadRecord(xlogreader, LastRec, PANIC, false); EndOfLog = EndRecPtr; - XLByteToPrevSeg(EndOfLog, endLogSegNo); + XLByteToSeg(EndOfLog, startLogSegNo); /* * Complain if we did not roll forward far enough to render the backup @@ -6687,14 +6727,14 @@ StartupXLOG(void) * we will use that below.) */ if (ArchiveRecoveryRequested) - exitArchiveRecovery(xlogreader->readPageTLI, endLogSegNo); + exitArchiveRecovery(xlogreader->readPageTLI, EndOfLog); /* * Prepare to write WAL starting at EndOfLog position, and init xlog * buffer cache using the block containing the last record from the * previous incarnation. */ - openLogSegNo = endLogSegNo; + openLogSegNo = startLogSegNo; openLogFile = XLogFileOpen(openLogSegNo); openLogOff = 0; Insert = &XLogCtl->Insert; |