* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.154 2004/08/03 20:32:32 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.155 2004/08/04 16:25:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
static time_t recoveryStopTime;
static bool recoveryStopAfter;
+/* constraint set by read_backup_label */
+static XLogRecPtr recoveryMinXlogOffset = { 0, 0 };
+
/*
* During normal operation, the only timeline we care about is ThisTimeLineID.
* During recovery, however, things are more complicated. To simplify life
#ifdef WAL_DEBUG
static void xlog_outrec(char *buf, XLogRecord *record);
#endif
+static bool read_backup_label(XLogRecPtr *checkPointLoc);
+static void remove_backup_label(void);
/*
* scenario has actually happened in the field several times with 7.1
* releases. Note that we cannot get here while InRedo is true, but if
* the bad page is brought in and marked dirty during recovery then
- * CreateCheckpoint will try to flush it at the end of recovery.)
+ * CreateCheckPoint will try to flush it at the end of recovery.)
*
* The current approach is to ERROR under normal conditions, but only
* WARNING during recovery, so that the system can be brought up even
recoveryTargetTLI,
ControlFile->checkPointCopy.ThisTimeLineID)));
- /*
- * Get the last valid checkpoint record. If the latest one according
- * to pg_control is broken, try the next-to-last one.
- */
- record = ReadCheckpointRecord(ControlFile->checkPoint, 1, buffer);
- if (record != NULL)
+ if (read_backup_label(&checkPointLoc))
{
- checkPointLoc = ControlFile->checkPoint;
- ereport(LOG,
- (errmsg("checkpoint record is at %X/%X",
- checkPointLoc.xlogid, checkPointLoc.xrecoff)));
+ /*
+ * When a backup_label file is present, we want to roll forward from
+ * the checkpoint it identifies, rather than using pg_control.
+ */
+ record = ReadCheckpointRecord(checkPointLoc, 0, buffer);
+ if (record != NULL)
+ {
+ ereport(LOG,
+ (errmsg("checkpoint record is at %X/%X",
+ checkPointLoc.xlogid, checkPointLoc.xrecoff)));
+ InRecovery = true; /* force recovery even if SHUTDOWNED */
+ }
+ else
+ {
+ ereport(PANIC,
+ (errmsg("could not locate required checkpoint record"),
+ errhint("If you are not restoring from a backup, try removing $PGDATA/backup_label.")));
+ }
}
else
{
- record = ReadCheckpointRecord(ControlFile->prevCheckPoint, 2, buffer);
+ /*
+ * Get the last valid checkpoint record. If the latest one according
+ * to pg_control is broken, try the next-to-last one.
+ */
+ checkPointLoc = ControlFile->checkPoint;
+ record = ReadCheckpointRecord(checkPointLoc, 1, buffer);
if (record != NULL)
{
- checkPointLoc = ControlFile->prevCheckPoint;
ereport(LOG,
- (errmsg("using previous checkpoint record at %X/%X",
- checkPointLoc.xlogid, checkPointLoc.xrecoff)));
- InRecovery = true; /* force recovery even if SHUTDOWNED */
+ (errmsg("checkpoint record is at %X/%X",
+ checkPointLoc.xlogid, checkPointLoc.xrecoff)));
}
else
- ereport(PANIC,
- (errmsg("could not locate a valid checkpoint record")));
+ {
+ checkPointLoc = ControlFile->prevCheckPoint;
+ record = ReadCheckpointRecord(checkPointLoc, 2, buffer);
+ if (record != NULL)
+ {
+ ereport(LOG,
+ (errmsg("using previous checkpoint record at %X/%X",
+ checkPointLoc.xlogid, checkPointLoc.xrecoff)));
+ InRecovery = true; /* force recovery even if SHUTDOWNED */
+ }
+ else
+ ereport(PANIC,
+ (errmsg("could not locate a valid checkpoint record")));
+ }
}
+
LastRec = RecPtr = checkPointLoc;
memcpy(&checkPoint, XLogRecGetData(record), sizeof(CheckPoint));
wasShutdown = (record->xl_info == XLOG_CHECKPOINT_SHUTDOWN);
}
else if (ControlFile->state != DB_SHUTDOWNED)
InRecovery = true;
+ else if (InArchiveRecovery)
+ {
+ /* force recovery due to presence of recovery.conf */
+ InRecovery = true;
+ }
/* REDO */
- if (InRecovery || InArchiveRecovery)
+ if (InRecovery)
{
int rmid;
- if (InRecovery)
- {
+ if (InArchiveRecovery)
ereport(LOG,
- (errmsg("database system was not properly shut down; "
- "automatic recovery in progress")));
- }
+ (errmsg("automatic recovery in progress")));
else
- {
- /* force recovery due to presence of recovery.conf */
- InRecovery = true;
ereport(LOG,
- (errmsg("automatic recovery in progress")));
- }
+ (errmsg("database system was not properly shut down; "
+ "automatic recovery in progress")));
ControlFile->state = DB_IN_RECOVERY;
ControlFile->time = time(NULL);
UpdateControlFile();
EndOfLog = EndRecPtr;
XLByteToPrevSeg(EndOfLog, endLogId, endLogSeg);
+ /*
+ * Complain if we did not roll forward far enough to render the backup
+ * dump consistent.
+ */
+ if (XLByteLT(EndOfLog, recoveryMinXlogOffset))
+ {
+ if (needNewTimeLine) /* stopped because of stop request */
+ ereport(FATAL,
+ (errmsg("requested recovery stop point is before end time of backup dump")));
+ else /* ran off end of WAL */
+ ereport(FATAL,
+ (errmsg("WAL ends before end time of backup dump")));
+ }
+
/*
* Consider whether we need to assign a new timeline ID.
*
* CreateCheckPoint operation; we don't want the broken primary
* checkpoint to become prevCheckPoint...
*/
- ControlFile->checkPoint = checkPointLoc;
+ if (XLByteEQ(checkPointLoc, ControlFile->prevCheckPoint))
+ ControlFile->checkPoint = checkPointLoc;
+
CreateCheckPoint(true, true);
/*
* Close down recovery environment
*/
XLogCloseRelationCache();
+
+ /*
+ * Now that we've checkpointed the recovery, it's safe to
+ * flush old backup_label, if present.
+ */
+ remove_backup_label();
}
/*
/*
* Subroutine to try to fetch and validate a prior checkpoint record.
- * whichChkpt = 1 for "primary", 2 for "secondary", merely informative
+ *
+ * whichChkpt identifies the checkpoint (merely for reporting purposes).
+ * 1 for "primary", 2 for "secondary", 0 for "other" (backup_label)
*/
static XLogRecord *
ReadCheckpointRecord(XLogRecPtr RecPtr,
if (!XRecOffIsValid(RecPtr.xrecoff))
{
- if (whichChkpt == 1)
- ereport(LOG,
- (errmsg("invalid primary checkpoint link in control file")));
- else
- ereport(LOG,
- (errmsg("invalid secondary checkpoint link in control file")));
+ switch (whichChkpt)
+ {
+ case 1:
+ ereport(LOG,
+ (errmsg("invalid primary checkpoint link in control file")));
+ break;
+ case 2:
+ ereport(LOG,
+ (errmsg("invalid secondary checkpoint link in control file")));
+ break;
+ default:
+ ereport(LOG,
+ (errmsg("invalid checkpoint link in backup_label file")));
+ break;
+ }
return NULL;
}
if (record == NULL)
{
- if (whichChkpt == 1)
- ereport(LOG,
- (errmsg("invalid primary checkpoint record")));
- else
- ereport(LOG,
- (errmsg("invalid secondary checkpoint record")));
+ switch (whichChkpt)
+ {
+ case 1:
+ ereport(LOG,
+ (errmsg("invalid primary checkpoint record")));
+ break;
+ case 2:
+ ereport(LOG,
+ (errmsg("invalid secondary checkpoint record")));
+ break;
+ default:
+ ereport(LOG,
+ (errmsg("invalid checkpoint record")));
+ break;
+ }
return NULL;
}
if (record->xl_rmid != RM_XLOG_ID)
{
- if (whichChkpt == 1)
- ereport(LOG,
- (errmsg("invalid resource manager ID in primary checkpoint record")));
- else
- ereport(LOG,
- (errmsg("invalid resource manager ID in secondary checkpoint record")));
+ switch (whichChkpt)
+ {
+ case 1:
+ ereport(LOG,
+ (errmsg("invalid resource manager ID in primary checkpoint record")));
+ break;
+ case 2:
+ ereport(LOG,
+ (errmsg("invalid resource manager ID in secondary checkpoint record")));
+ break;
+ default:
+ ereport(LOG,
+ (errmsg("invalid resource manager ID in checkpoint record")));
+ break;
+ }
return NULL;
}
if (record->xl_info != XLOG_CHECKPOINT_SHUTDOWN &&
record->xl_info != XLOG_CHECKPOINT_ONLINE)
{
- if (whichChkpt == 1)
- ereport(LOG,
- (errmsg("invalid xl_info in primary checkpoint record")));
- else
- ereport(LOG,
- (errmsg("invalid xl_info in secondary checkpoint record")));
+ switch (whichChkpt)
+ {
+ case 1:
+ ereport(LOG,
+ (errmsg("invalid xl_info in primary checkpoint record")));
+ break;
+ case 2:
+ ereport(LOG,
+ (errmsg("invalid xl_info in secondary checkpoint record")));
+ break;
+ default:
+ ereport(LOG,
+ (errmsg("invalid xl_info in checkpoint record")));
+ break;
+ }
return NULL;
}
if (record->xl_len != sizeof(CheckPoint))
{
- if (whichChkpt == 1)
- ereport(LOG,
- (errmsg("invalid length of primary checkpoint record")));
- else
- ereport(LOG,
- (errmsg("invalid length of secondary checkpoint record")));
+ switch (whichChkpt)
+ {
+ case 1:
+ ereport(LOG,
+ (errmsg("invalid length of primary checkpoint record")));
+ break;
+ case 2:
+ ereport(LOG,
+ (errmsg("invalid length of secondary checkpoint record")));
+ break;
+ default:
+ ereport(LOG,
+ (errmsg("invalid length of checkpoint record")));
+ break;
+ }
return NULL;
}
return record;
text *backupid = PG_GETARG_TEXT_P(0);
text *result;
char *backupidstr;
+ XLogRecPtr checkpointloc;
XLogRecPtr startpoint;
time_t stamp_time;
char strfbuf[128];
- char labelfilename[MAXPGPATH];
+ char labelfilepath[MAXPGPATH];
char xlogfilename[MAXFNAMELEN];
uint32 _logId;
uint32 _logSeg;
backupidstr = DatumGetCString(DirectFunctionCall1(textout,
PointerGetDatum(backupid)));
/*
- * The oldest point in WAL that would be needed to restore starting from
- * the most recent checkpoint is precisely the RedoRecPtr.
+ * Force a CHECKPOINT. This is not strictly necessary, but it seems
+ * like a good idea to minimize the amount of past WAL needed to use the
+ * backup. Also, this guarantees that two successive backup runs
+ * will have different checkpoint positions and hence different history
+ * file names, even if nothing happened in between.
+ */
+ RequestCheckpoint(true);
+ /*
+ * Now we need to fetch the checkpoint record location, and also its
+ * REDO pointer. The oldest point in WAL that would be needed to restore
+ * starting from the checkpoint is precisely the REDO pointer.
*/
- startpoint = GetRedoRecPtr();
+ LWLockAcquire(ControlFileLock, LW_EXCLUSIVE);
+ checkpointloc = ControlFile->checkPoint;
+ startpoint = ControlFile->checkPointCopy.redo;
+ LWLockRelease(ControlFileLock);
+
XLByteToSeg(startpoint, _logId, _logSeg);
XLogFileName(xlogfilename, ThisTimeLineID, _logId, _logSeg);
/*
/*
* Check for existing backup label --- implies a backup is already running
*/
- snprintf(labelfilename, MAXPGPATH, "%s/backup_label", DataDir);
- if (stat(labelfilename, &stat_buf) != 0)
+ snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
+ if (stat(labelfilepath, &stat_buf) != 0)
{
if (errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat \"%s\": %m",
- labelfilename)));
+ labelfilepath)));
}
else
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("a backup is already in progress"),
errhint("If you're sure there is no backup in progress, remove file \"%s\" and try again.",
- labelfilename)));
+ labelfilepath)));
/*
* Okay, write the file
*/
- fp = AllocateFile(labelfilename, "w");
+ fp = AllocateFile(labelfilepath, "w");
if (!fp)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create file \"%s\": %m",
- labelfilename)));
+ labelfilepath)));
fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n",
startpoint.xlogid, startpoint.xrecoff, xlogfilename);
+ fprintf(fp, "CHECKPOINT LOCATION: %X/%X\n",
+ checkpointloc.xlogid, checkpointloc.xrecoff);
fprintf(fp, "START TIME: %s\n", strfbuf);
fprintf(fp, "LABEL: %s\n", backupidstr);
if (fflush(fp) || ferror(fp) || FreeFile(fp))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write file \"%s\": %m",
- labelfilename)));
+ labelfilepath)));
/*
* We're done. As a convenience, return the starting WAL offset.
*/
XLogRecPtr stoppoint;
time_t stamp_time;
char strfbuf[128];
- char labelfilename[MAXPGPATH];
- char histfilename[MAXPGPATH];
+ char labelfilepath[MAXPGPATH];
+ char histfilepath[MAXPGPATH];
char startxlogfilename[MAXFNAMELEN];
char stopxlogfilename[MAXFNAMELEN];
uint32 _logId;
/*
* Open the existing label file
*/
- snprintf(labelfilename, MAXPGPATH, "%s/backup_label", DataDir);
- lfp = AllocateFile(labelfilename, "r");
+ snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
+ lfp = AllocateFile(labelfilepath, "r");
if (!lfp)
{
if (errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m",
- labelfilename)));
+ labelfilepath)));
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("a backup is not in progress")));
&ch) != 4 || ch != '\n')
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
- errmsg("invalid data in file \"%s\"", labelfilename)));
+ errmsg("invalid data in file \"%s\"", labelfilepath)));
/*
* Write the backup history file
*/
XLByteToSeg(startpoint, _logId, _logSeg);
- BackupHistoryFilePath(histfilename, ThisTimeLineID, _logId, _logSeg,
+ BackupHistoryFilePath(histfilepath, ThisTimeLineID, _logId, _logSeg,
startpoint.xrecoff % XLogSegSize);
- fp = AllocateFile(histfilename, "w");
+ fp = AllocateFile(histfilepath, "w");
if (!fp)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create file \"%s\": %m",
- histfilename)));
+ histfilepath)));
fprintf(fp, "START WAL LOCATION: %X/%X (file %s)\n",
startpoint.xlogid, startpoint.xrecoff, startxlogfilename);
fprintf(fp, "STOP WAL LOCATION: %X/%X (file %s)\n",
stoppoint.xlogid, stoppoint.xrecoff, stopxlogfilename);
- /* transfer start time and label lines from label to history file */
+ /* transfer remaining lines from label to history file */
while ((ich = fgetc(lfp)) != EOF)
fputc(ich, fp);
fprintf(fp, "STOP TIME: %s\n", strfbuf);
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write file \"%s\": %m",
- histfilename)));
+ histfilepath)));
/*
* Close and remove the backup label file
*/
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m",
- labelfilename)));
- if (unlink(labelfilename) != 0)
+ labelfilepath)));
+ if (unlink(labelfilepath) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m",
- labelfilename)));
+ labelfilepath)));
/*
* Notify archiver that history file may be archived immediately
*/
if (XLogArchivingActive())
{
- BackupHistoryFileName(histfilename, ThisTimeLineID, _logId, _logSeg,
+ BackupHistoryFileName(histfilepath, ThisTimeLineID, _logId, _logSeg,
startpoint.xrecoff % XLogSegSize);
- XLogArchiveNotify(histfilename);
+ XLogArchiveNotify(histfilepath);
}
/*
* We're done. As a convenience, return the ending WAL offset.
CStringGetDatum(stopxlogfilename)));
PG_RETURN_TEXT_P(result);
}
+
+/*
+ * read_backup_label: check to see if a backup_label file is present
+ *
+ * If we see a backup_label during recovery, we assume that we are recovering
+ * from a backup dump file, and we therefore roll forward from the checkpoint
+ * identified by the label file, NOT what pg_control says. This avoids the
+ * problem that pg_control might have been archived one or more checkpoints
+ * later than the start of the dump, and so if we rely on it as the start
+ * point, we will fail to restore a consistent database state.
+ *
+ * We also attempt to retrieve the corresponding backup history file.
+ * If successful, set recoveryMinXlogOffset to constrain valid PITR stopping
+ * points.
+ *
+ * Returns TRUE if a backup_label was found (and fills the checkpoint
+ * location into *checkPointLoc); returns FALSE if not.
+ */
+static bool
+read_backup_label(XLogRecPtr *checkPointLoc)
+{
+ XLogRecPtr startpoint;
+ XLogRecPtr stoppoint;
+ char labelfilepath[MAXPGPATH];
+ char histfilename[MAXFNAMELEN];
+ char histfilepath[MAXPGPATH];
+ char startxlogfilename[MAXFNAMELEN];
+ char stopxlogfilename[MAXFNAMELEN];
+ TimeLineID tli;
+ uint32 _logId;
+ uint32 _logSeg;
+ FILE *lfp;
+ FILE *fp;
+ char ch;
+
+ /*
+ * See if label file is present
+ */
+ snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
+ lfp = AllocateFile(labelfilepath, "r");
+ if (!lfp)
+ {
+ if (errno != ENOENT)
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m",
+ labelfilepath)));
+ return false; /* it's not there, all is fine */
+ }
+ /*
+ * Read and parse the START WAL LOCATION and CHECKPOINT lines (this code
+ * is pretty crude, but we are not expecting any variability in the file
+ * format).
+ */
+ if (fscanf(lfp, "START WAL LOCATION: %X/%X (file %08X%16s)%c",
+ &startpoint.xlogid, &startpoint.xrecoff, &tli,
+ startxlogfilename, &ch) != 5 || ch != '\n')
+ ereport(FATAL,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("invalid data in file \"%s\"", labelfilepath)));
+ if (fscanf(lfp, "CHECKPOINT LOCATION: %X/%X%c",
+ &checkPointLoc->xlogid, &checkPointLoc->xrecoff,
+ &ch) != 3 || ch != '\n')
+ ereport(FATAL,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("invalid data in file \"%s\"", labelfilepath)));
+ if (ferror(lfp) || FreeFile(lfp))
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m",
+ labelfilepath)));
+ /*
+ * Try to retrieve the backup history file (no error if we can't)
+ */
+ XLByteToSeg(startpoint, _logId, _logSeg);
+ BackupHistoryFileName(histfilename, tli, _logId, _logSeg,
+ startpoint.xrecoff % XLogSegSize);
+
+ if (InArchiveRecovery)
+ RestoreArchivedFile(histfilepath, histfilename, "RECOVERYHISTORY", 0);
+ else
+ BackupHistoryFilePath(histfilepath, tli, _logId, _logSeg,
+ startpoint.xrecoff % XLogSegSize);
+
+ fp = AllocateFile(histfilepath, "r");
+ if (fp)
+ {
+ /*
+ * Parse history file to identify stop point.
+ */
+ if (fscanf(fp, "START WAL LOCATION: %X/%X (file %24s)%c",
+ &startpoint.xlogid, &startpoint.xrecoff, startxlogfilename,
+ &ch) != 4 || ch != '\n')
+ ereport(FATAL,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("invalid data in file \"%s\"", histfilename)));
+ if (fscanf(fp, "STOP WAL LOCATION: %X/%X (file %24s)%c",
+ &stoppoint.xlogid, &stoppoint.xrecoff, stopxlogfilename,
+ &ch) != 4 || ch != '\n')
+ ereport(FATAL,
+ (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+ errmsg("invalid data in file \"%s\"", histfilename)));
+ recoveryMinXlogOffset = stoppoint;
+ if (ferror(fp) || FreeFile(fp))
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg("could not read file \"%s\": %m",
+ histfilepath)));
+ }
+
+ return true;
+}
+
+/*
+ * remove_backup_label: remove any extant backup_label after successful
+ * recovery. Once we have completed the end-of-recovery checkpoint there
+ * is no reason to have to replay from the start point indicated by the
+ * label (and indeed we'll probably have removed/recycled the needed WAL
+ * segments), so remove the label to prevent trouble in later crash recoveries.
+ */
+static void
+remove_backup_label(void)
+{
+ char labelfilepath[MAXPGPATH];
+
+ snprintf(labelfilepath, MAXPGPATH, "%s/backup_label", DataDir);
+ if (unlink(labelfilepath) != 0)
+ if (errno != ENOENT)
+ ereport(FATAL,
+ (errcode_for_file_access(),
+ errmsg("could not remove file \"%s\": %m",
+ labelfilepath)));
+}
projects / postgresql / commitdiff