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Split off functions related to timeline history files and XLOG archiving.

Browse Source 
This is just refactoring, to make the functions accessible outside xlog.c.
A followup patch will make use of that, to allow fetching timeline history
files over streaming replication.
pull/3/head
Heikki Linnakangas 13 years ago
parent 0899556e92
commit d5497b95f3
6 changed files with 1058 additions and 929 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 3
      src/backend/access/transam/Makefile
  2. 378
      src/backend/access/transam/timeline.c
  3. 988
      src/backend/access/transam/xlog.c
  4. 572
      src/backend/access/transam/xlogarchive.c
  5. 23
      src/include/access/timeline.h
  6. 23
      src/include/access/xlog_internal.h

3
src/backend/access/transam/Makefile
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@ -13,7 +13,8 @@ top_builddir = ../../../..
include $(top_builddir)/src/Makefile.global
OBJS = clog.o transam.o varsup.o xact.o rmgr.o slru.o subtrans.o multixact.o \
twophase.o twophase_rmgr.o xlog.o xlogfuncs.o xlogutils.o
timeline.o twophase.o twophase_rmgr.o xlog.o xlogarchive.o xlogfuncs.o \
xlogutils.o
include $(top_srcdir)/src/backend/common.mk

378
src/backend/access/transam/timeline.c
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@ -0,0 +1,378 @@
/*-------------------------------------------------------------------------
*
* timeline.c
* Functions for reading and writing timeline history files.
*
* A timeline history file lists the timeline changes of the timeline, in
* a simple text format. They are archived along with the WAL segments.
*
* The files are named like "<WAL segment>.history". For example, if the
* database starts up and switches to timeline 5, while processing WAL
* segment 000000030000002A00000006 (the old timeline was 3), the timeline
* history file would be called "000000050000002A00000006.history".
*
* Each line in the file represents a timeline switch:
*
* <parentTLI> <xlogfname> <reason>
*
* parentTLI ID of the parent timeline
* xlogfname filename of the WAL segment where the switch happened
* reason human-readable explanation of why the timeline was changed
*
* The fields are separated by tabs. Lines beginning with # are comments, and
* are ignored. Empty lines are also ignored.
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/backend/access/transam/timeline.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <stdio.h>
#include <unistd.h>
#include "access/timeline.h"
#include "access/xlog_internal.h"
#include "access/xlogdefs.h"
#include "storage/fd.h"
/*
* Try to read a timeline's history file.
*
* If successful, return the list of component TLIs (the given TLI followed by
* its ancestor TLIs). If we can't find the history file, assume that the
* timeline has no parents, and return a list of just the specified timeline
* ID.
*/
List *
readTimeLineHistory(TimeLineID targetTLI)
{
List *result;
char path[MAXPGPATH];
char histfname[MAXFNAMELEN];
char fline[MAXPGPATH];
FILE *fd;
/* Timeline 1 does not have a history file, so no need to check */
if (targetTLI == 1)
return list_make1_int((int) targetTLI);
if (InArchiveRecovery)
{
TLHistoryFileName(histfname, targetTLI);
RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0);
}
else
TLHistoryFilePath(path, targetTLI);
fd = AllocateFile(path, "r");
if (fd == NULL)
{
if (errno != ENOENT)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not open file \"%s\": %m", path)));
/* Not there, so assume no parents */
return list_make1_int((int) targetTLI);
}
result = NIL;
/*
* Parse the file...
*/
while (fgets(fline, sizeof(fline), fd) != NULL)
{
/* skip leading whitespace and check for # comment */
char *ptr;
char *endptr;
TimeLineID tli;
for (ptr = fline; *ptr; ptr++)
{
if (!isspace((unsigned char) *ptr))
break;
}
if (*ptr == '\0' || *ptr == '#')
continue;
/* expect a numeric timeline ID as first field of line */
tli = (TimeLineID) strtoul(ptr, &endptr, 0);
if (endptr == ptr)
ereport(FATAL,
(errmsg("syntax error in history file: %s", fline),
errhint("Expected a numeric timeline ID.")));
if (result &&
tli <= (TimeLineID) linitial_int(result))
ereport(FATAL,
(errmsg("invalid data in history file: %s", fline),
errhint("Timeline IDs must be in increasing sequence.")));
/* Build list with newest item first */
result = lcons_int((int) tli, result);
/* we ignore the remainder of each line */
}
FreeFile(fd);
if (result &&
targetTLI <= (TimeLineID) linitial_int(result))
ereport(FATAL,
(errmsg("invalid data in history file \"%s\"", path),
errhint("Timeline IDs must be less than child timeline's ID.")));
result = lcons_int((int) targetTLI, result);
ereport(DEBUG3,
(errmsg_internal("history of timeline %u is %s",
targetTLI, nodeToString(result))));
return result;
}
/*
* Probe whether a timeline history file exists for the given timeline ID
*/
bool
existsTimeLineHistory(TimeLineID probeTLI)
{
char path[MAXPGPATH];
char histfname[MAXFNAMELEN];
FILE *fd;
/* Timeline 1 does not have a history file, so no need to check */
if (probeTLI == 1)
return false;
if (InArchiveRecovery)
{
TLHistoryFileName(histfname, probeTLI);
RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0);
}
else
TLHistoryFilePath(path, probeTLI);
fd = AllocateFile(path, "r");
if (fd != NULL)
{
FreeFile(fd);
return true;
}
else
{
if (errno != ENOENT)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not open file \"%s\": %m", path)));
return false;
}
}
/*
* Find the newest existing timeline, assuming that startTLI exists.
*
* Note: while this is somewhat heuristic, it does positively guarantee
* that (result + 1) is not a known timeline, and therefore it should
* be safe to assign that ID to a new timeline.
*/
TimeLineID
findNewestTimeLine(TimeLineID startTLI)
{
TimeLineID newestTLI;
TimeLineID probeTLI;
/*
* The algorithm is just to probe for the existence of timeline history
* files. XXX is it useful to allow gaps in the sequence?
*/
newestTLI = startTLI;
for (probeTLI = startTLI + 1;; probeTLI++)
{
if (existsTimeLineHistory(probeTLI))
{
newestTLI = probeTLI; /* probeTLI exists */
}
else
{
/* doesn't exist, assume we're done */
break;
}
}
return newestTLI;
}
/*
* Create a new timeline history file.
*
* newTLI: ID of the new timeline
* parentTLI: ID of its immediate parent
* endTLI et al: ID of the last used WAL file, for annotation purposes
* reason: human-readable explanation of why the timeline was switched
*
* Currently this is only used at the end recovery, and so there are no locking
* considerations. But we should be just as tense as XLogFileInit to avoid
* emplacing a bogus file.
*/
void
writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
TimeLineID endTLI, XLogSegNo endLogSegNo, char *reason)
{
char path[MAXPGPATH];
char tmppath[MAXPGPATH];
char histfname[MAXFNAMELEN];
char xlogfname[MAXFNAMELEN];
char buffer[BLCKSZ];
int srcfd;
int fd;
int nbytes;
Assert(newTLI > parentTLI); /* else bad selection of newTLI */
/*
* Write into a temp file name.
*/
snprintf(tmppath, MAXPGPATH, XLOGDIR "/xlogtemp.%d", (int) getpid());
unlink(tmppath);
/* do not use get_sync_bit() here --- want to fsync only at end of fill */
fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL,
S_IRUSR | S_IWUSR);
if (fd < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create file \"%s\": %m", tmppath)));
/*
* If a history file exists for the parent, copy it verbatim
*/
if (InArchiveRecovery)
{
TLHistoryFileName(histfname, parentTLI);
RestoreArchivedFile(path, histfname, "RECOVERYHISTORY", 0);
}
else
TLHistoryFilePath(path, parentTLI);
srcfd = BasicOpenFile(path, O_RDONLY, 0);
if (srcfd < 0)
{
if (errno != ENOENT)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open file \"%s\": %m", path)));
/* Not there, so assume parent has no parents */
}
else
{
for (;;)
{
errno = 0;
nbytes = (int) read(srcfd, buffer, sizeof(buffer));
if (nbytes < 0 || errno != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m", path)));
if (nbytes == 0)
break;
errno = 0;
if ((int) write(fd, buffer, nbytes) != nbytes)
{
int save_errno = errno;
/*
* If we fail to make the file, delete it to release disk
* space
*/
unlink(tmppath);
/*
* if write didn't set errno, assume problem is no disk space
*/
errno = save_errno ? save_errno : ENOSPC;
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m", tmppath)));
}
}
close(srcfd);
}
/*
* Append one line with the details of this timeline split.
*
* If we did have a parent file, insert an extra newline just in case the
* parent file failed to end with one.
*/
XLogFileName(xlogfname, endTLI, endLogSegNo);
snprintf(buffer, sizeof(buffer),
"%s%u\t%s\t%s\n",
(srcfd < 0) ? "" : "\n",
parentTLI,
xlogfname,
reason);
nbytes = strlen(buffer);
errno = 0;
if ((int) write(fd, buffer, nbytes) != nbytes)
{
int save_errno = errno;
/*
* If we fail to make the file, delete it to release disk space
*/
unlink(tmppath);
/* if write didn't set errno, assume problem is no disk space */
errno = save_errno ? save_errno : ENOSPC;
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write to file \"%s\": %m", tmppath)));
}
if (pg_fsync(fd) != 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not fsync file \"%s\": %m", tmppath)));
if (close(fd))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not close file \"%s\": %m", tmppath)));
/*
* Now move the completed history file into place with its final name.
*/
TLHistoryFilePath(path, newTLI);
/*
* Prefer link() to rename() here just to be really sure that we don't
* overwrite an existing logfile. However, there shouldn't be one, so
* rename() is an acceptable substitute except for the truly paranoid.
*/
#if HAVE_WORKING_LINK
if (link(tmppath, path) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not link file \"%s\" to \"%s\": %m",
tmppath, path)));
unlink(tmppath);
#else
if (rename(tmppath, path) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename file \"%s\" to \"%s\": %m",
tmppath, path)));
#endif
}

988
src/backend/access/transam/xlog.c
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572
src/backend/access/transam/xlogarchive.c
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/*-------------------------------------------------------------------------
*
* xlogarchive.c
* Functions for archiving WAL files and restoring from the archive.
*
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/backend/access/transam/xlogarchive.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <unistd.h>
#include "access/xlog_internal.h"
#include "miscadmin.h"
#include "postmaster/startup.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/lwlock.h"
#include "storage/pmsignal.h"
/*
* Attempt to retrieve the specified file from off-line archival storage.
* If successful, fill "path" with its complete path (note that this will be
* a temp file name that doesn't follow the normal naming convention), and
* return TRUE.
*
* If not successful, fill "path" with the name of the normal on-line file
* (which may or may not actually exist, but we'll try to use it), and return
* FALSE.
*
* For fixed-size files, the caller may pass the expected size as an
* additional crosscheck on successful recovery. If the file size is not
* known, set expectedSize = 0.
*/
bool
RestoreArchivedFile(char *path, const char *xlogfname,
const char *recovername, off_t expectedSize)
{
char xlogpath[MAXPGPATH];
char xlogRestoreCmd[MAXPGPATH];
char lastRestartPointFname[MAXPGPATH];
char *dp;
char *endp;
const char *sp;
int rc;
bool signaled;
struct stat stat_buf;
XLogSegNo restartSegNo;
XLogRecPtr restartRedoPtr;
TimeLineID restartTli;
/* In standby mode, restore_command might not be supplied */
if (recoveryRestoreCommand == NULL)
goto not_available;
/*
* When doing archive recovery, we always prefer an archived log file even
* if a file of the same name exists in XLOGDIR. The reason is that the
* file in XLOGDIR could be an old, un-filled or partly-filled version
* that was copied and restored as part of backing up $PGDATA.
*
* We could try to optimize this slightly by checking the local copy
* lastchange timestamp against the archived copy, but we have no API to
* do this, nor can we guarantee that the lastchange timestamp was
* preserved correctly when we copied to archive. Our aim is robustness,
* so we elect not to do this.
*
* If we cannot obtain the log file from the archive, however, we will try
* to use the XLOGDIR file if it exists. This is so that we can make use
* of log segments that weren't yet transferred to the archive.
*
* Notice that we don't actually overwrite any files when we copy back
* from archive because the restore_command may inadvertently
* restore inappropriate xlogs, or they may be corrupt, so we may wish to
* fallback to the segments remaining in current XLOGDIR later. The
* copy-from-archive filename is always the same, ensuring that we don't
* run out of disk space on long recoveries.
*/
snprintf(xlogpath, MAXPGPATH, XLOGDIR "/%s", recovername);
/*
* Make sure there is no existing file named recovername.
*/
if (stat(xlogpath, &stat_buf) != 0)
{
if (errno != ENOENT)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m",
xlogpath)));
}
else
{
if (unlink(xlogpath) != 0)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m",
xlogpath)));
}
/*
* Calculate the archive file cutoff point for use during log shipping
* replication. All files earlier than this point can be deleted from the
* archive, though there is no requirement to do so.
*
* We initialise this with the filename of an InvalidXLogRecPtr, which
* will prevent the deletion of any WAL files from the archive because of
* the alphabetic sorting property of WAL filenames.
*
* Once we have successfully located the redo pointer of the checkpoint
* from which we start recovery we never request a file prior to the redo
* pointer of the last restartpoint. When redo begins we know that we have
* successfully located it, so there is no need for additional status
* flags to signify the point when we can begin deleting WAL files from
* the archive.
*/
GetOldestRestartPoint(&restartRedoPtr, &restartTli);
if (!XLogRecPtrIsInvalid(restartRedoPtr))
{
XLByteToSeg(restartRedoPtr, restartSegNo);
XLogFileName(lastRestartPointFname, restartTli, restartSegNo);
/* we shouldn't need anything earlier than last restart point */
Assert(strcmp(lastRestartPointFname, xlogfname) <= 0);
}
else
XLogFileName(lastRestartPointFname, 0, 0L);
/*
* construct the command to be executed
*/
dp = xlogRestoreCmd;
endp = xlogRestoreCmd + MAXPGPATH - 1;
*endp = '\0';
for (sp = recoveryRestoreCommand; *sp; sp++)
{
if (*sp == '%')
{
switch (sp[1])
{
case 'p':
/* %p: relative path of target file */
sp++;
StrNCpy(dp, xlogpath, endp - dp);
make_native_path(dp);
dp += strlen(dp);
break;
case 'f':
/* %f: filename of desired file */
sp++;
StrNCpy(dp, xlogfname, endp - dp);
dp += strlen(dp);
break;
case 'r':
/* %r: filename of last restartpoint */
sp++;
StrNCpy(dp, lastRestartPointFname, endp - dp);
dp += strlen(dp);
break;
case '%':
/* convert %% to a single % */
sp++;
if (dp < endp)
*dp++ = *sp;
break;
default:
/* otherwise treat the % as not special */
if (dp < endp)
*dp++ = *sp;
break;
}
}
else
{
if (dp < endp)
*dp++ = *sp;
}
}
*dp = '\0';
ereport(DEBUG3,
(errmsg_internal("executing restore command \"%s\"",
xlogRestoreCmd)));
/*
* Check signals before restore command and reset afterwards.
*/
PreRestoreCommand();
/*
* Copy xlog from archival storage to XLOGDIR
*/
rc = system(xlogRestoreCmd);
PostRestoreCommand();
if (rc == 0)
{
/*
* command apparently succeeded, but let's make sure the file is
* really there now and has the correct size.
*/
if (stat(xlogpath, &stat_buf) == 0)
{
if (expectedSize > 0 && stat_buf.st_size != expectedSize)
{
int elevel;
/*
* If we find a partial file in standby mode, we assume it's
* because it's just being copied to the archive, and keep
* trying.
*
* Otherwise treat a wrong-sized file as FATAL to ensure the
* DBA would notice it, but is that too strong? We could try
* to plow ahead with a local copy of the file ... but the
* problem is that there probably isn't one, and we'd
* incorrectly conclude we've reached the end of WAL and we're
* done recovering ...
*/
if (StandbyMode && stat_buf.st_size < expectedSize)
elevel = DEBUG1;
else
elevel = FATAL;
ereport(elevel,
(errmsg("archive file \"%s\" has wrong size: %lu instead of %lu",
xlogfname,
(unsigned long) stat_buf.st_size,
(unsigned long) expectedSize)));
return false;
}
else
{
ereport(LOG,
(errmsg("restored log file \"%s\" from archive",
xlogfname)));
strcpy(path, xlogpath);
return true;
}
}
else
{
/* stat failed */
if (errno != ENOENT)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m",
xlogpath)));
}
}
/*
* Remember, we rollforward UNTIL the restore fails so failure here is
* just part of the process... that makes it difficult to determine
* whether the restore failed because there isn't an archive to restore,
* or because the administrator has specified the restore program
* incorrectly. We have to assume the former.
*
* However, if the failure was due to any sort of signal, it's best to
* punt and abort recovery. (If we "return false" here, upper levels will
* assume that recovery is complete and start up the database!) It's
* essential to abort on child SIGINT and SIGQUIT, because per spec
* system() ignores SIGINT and SIGQUIT while waiting; if we see one of
* those it's a good bet we should have gotten it too.
*
* On SIGTERM, assume we have received a fast shutdown request, and exit
* cleanly. It's pure chance whether we receive the SIGTERM first, or the
* child process. If we receive it first, the signal handler will call
* proc_exit, otherwise we do it here. If we or the child process received
* SIGTERM for any other reason than a fast shutdown request, postmaster
* will perform an immediate shutdown when it sees us exiting
* unexpectedly.
*
* Per the Single Unix Spec, shells report exit status > 128 when a called
* command died on a signal. Also, 126 and 127 are used to report
* problems such as an unfindable command; treat those as fatal errors
* too.
*/
if (WIFSIGNALED(rc) && WTERMSIG(rc) == SIGTERM)
proc_exit(1);
signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125;
ereport(signaled ? FATAL : DEBUG2,
(errmsg("could not restore file \"%s\" from archive: return code %d",
xlogfname, rc)));
not_available:
/*
* if an archived file is not available, there might still be a version of
* this file in XLOGDIR, so return that as the filename to open.
*
* In many recovery scenarios we expect this to fail also, but if so that
* just means we've reached the end of WAL.
*/
snprintf(path, MAXPGPATH, XLOGDIR "/%s", xlogfname);
return false;
}
/*
* Attempt to execute an external shell command during recovery.
*
* 'command' is the shell command to be executed, 'commandName' is a
* human-readable name describing the command emitted in the logs. If
* 'failOnSignal' is true and the command is killed by a signal, a FATAL
* error is thrown. Otherwise a WARNING is emitted.
*
* This is currently used for recovery_end_command and archive_cleanup_command.
*/
void
ExecuteRecoveryCommand(char *command, char *commandName, bool failOnSignal)
{
char xlogRecoveryCmd[MAXPGPATH];
char lastRestartPointFname[MAXPGPATH];
char *dp;
char *endp;
const char *sp;
int rc;
bool signaled;
XLogSegNo restartSegNo;
XLogRecPtr restartRedoPtr;
TimeLineID restartTli;
Assert(command && commandName);
/*
* Calculate the archive file cutoff point for use during log shipping
* replication. All files earlier than this point can be deleted from the
* archive, though there is no requirement to do so.
*/
GetOldestRestartPoint(&restartRedoPtr, &restartTli);
XLByteToSeg(restartRedoPtr, restartSegNo);
XLogFileName(lastRestartPointFname, restartTli, restartSegNo);
LWLockRelease(ControlFileLock);
/*
* construct the command to be executed
*/
dp = xlogRecoveryCmd;
endp = xlogRecoveryCmd + MAXPGPATH - 1;
*endp = '\0';
for (sp = command; *sp; sp++)
{
if (*sp == '%')
{
switch (sp[1])
{
case 'r':
/* %r: filename of last restartpoint */
sp++;
StrNCpy(dp, lastRestartPointFname, endp - dp);
dp += strlen(dp);
break;
case '%':
/* convert %% to a single % */
sp++;
if (dp < endp)
*dp++ = *sp;
break;
default:
/* otherwise treat the % as not special */
if (dp < endp)
*dp++ = *sp;
break;
}
}
else
{
if (dp < endp)
*dp++ = *sp;
}
}
*dp = '\0';
ereport(DEBUG3,
(errmsg_internal("executing %s \"%s\"", commandName, command)));
/*
* execute the constructed command
*/
rc = system(xlogRecoveryCmd);
if (rc != 0)
{
/*
* If the failure was due to any sort of signal, it's best to punt and
* abort recovery. See also detailed comments on signals in
* RestoreArchivedFile().
*/
signaled = WIFSIGNALED(rc) || WEXITSTATUS(rc) > 125;
ereport((signaled && failOnSignal) ? FATAL : WARNING,
/*------
translator: First %s represents a recovery.conf parameter name like
"recovery_end_command", and the 2nd is the value of that parameter. */
(errmsg("%s \"%s\": return code %d", commandName,
command, rc)));
}
}
/*
* XLogArchiveNotify
*
* Create an archive notification file
*
* The name of the notification file is the message that will be picked up
* by the archiver, e.g. we write 0000000100000001000000C6.ready
* and the archiver then knows to archive XLOGDIR/0000000100000001000000C6,
* then when complete, rename it to 0000000100000001000000C6.done
*/
void
XLogArchiveNotify(const char *xlog)
{
char archiveStatusPath[MAXPGPATH];
FILE *fd;
/* insert an otherwise empty file called <XLOG>.ready */
StatusFilePath(archiveStatusPath, xlog, ".ready");
fd = AllocateFile(archiveStatusPath, "w");
if (fd == NULL)
{
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not create archive status file \"%s\": %m",
archiveStatusPath)));
return;
}
if (FreeFile(fd))
{
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not write archive status file \"%s\": %m",
archiveStatusPath)));
return;
}
/* Notify archiver that it's got something to do */
if (IsUnderPostmaster)
SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER);
}
/*
* Convenience routine to notify using segment number representation of filename
*/
void
XLogArchiveNotifySeg(XLogSegNo segno)
{
char xlog[MAXFNAMELEN];
XLogFileName(xlog, ThisTimeLineID, segno);
XLogArchiveNotify(xlog);
}
/*
* XLogArchiveCheckDone
*
* This is called when we are ready to delete or recycle an old XLOG segment
* file or backup history file. If it is okay to delete it then return true.
* If it is not time to delete it, make sure a .ready file exists, and return
* false.
*
* If <XLOG>.done exists, then return true; else if <XLOG>.ready exists,
* then return false; else create <XLOG>.ready and return false.
*
* The reason we do things this way is so that if the original attempt to
* create <XLOG>.ready fails, we'll retry during subsequent checkpoints.
*/
bool
XLogArchiveCheckDone(const char *xlog)
{
char archiveStatusPath[MAXPGPATH];
struct stat stat_buf;
/* Always deletable if archiving is off */
if (!XLogArchivingActive())
return true;
/* First check for .done --- this means archiver is done with it */
StatusFilePath(archiveStatusPath, xlog, ".done");
if (stat(archiveStatusPath, &stat_buf) == 0)
return true;
/* check for .ready --- this means archiver is still busy with it */
StatusFilePath(archiveStatusPath, xlog, ".ready");
if (stat(archiveStatusPath, &stat_buf) == 0)
return false;
/* Race condition --- maybe archiver just finished, so recheck */
StatusFilePath(archiveStatusPath, xlog, ".done");
if (stat(archiveStatusPath, &stat_buf) == 0)
return true;
/* Retry creation of the .ready file */
XLogArchiveNotify(xlog);
return false;
}
/*
* XLogArchiveIsBusy
*
* Check to see if an XLOG segment file is still unarchived.
* This is almost but not quite the inverse of XLogArchiveCheckDone: in
* the first place we aren't chartered to recreate the .ready file, and
* in the second place we should consider that if the file is already gone
* then it's not busy. (This check is needed to handle the race condition
* that a checkpoint already deleted the no-longer-needed file.)
*/
bool
XLogArchiveIsBusy(const char *xlog)
{
char archiveStatusPath[MAXPGPATH];
struct stat stat_buf;
/* First check for .done --- this means archiver is done with it */
StatusFilePath(archiveStatusPath, xlog, ".done");
if (stat(archiveStatusPath, &stat_buf) == 0)
return false;
/* check for .ready --- this means archiver is still busy with it */
StatusFilePath(archiveStatusPath, xlog, ".ready");
if (stat(archiveStatusPath, &stat_buf) == 0)
return true;
/* Race condition --- maybe archiver just finished, so recheck */
StatusFilePath(archiveStatusPath, xlog, ".done");
if (stat(archiveStatusPath, &stat_buf) == 0)
return false;
/*
* Check to see if the WAL file has been removed by checkpoint, which
* implies it has already been archived, and explains why we can't see a
* status file for it.
*/
snprintf(archiveStatusPath, MAXPGPATH, XLOGDIR "/%s", xlog);
if (stat(archiveStatusPath, &stat_buf) != 0 &&
errno == ENOENT)
return false;
return true;
}
/*
* XLogArchiveCleanup
*
* Cleanup archive notification file(s) for a particular xlog segment
*/
void
XLogArchiveCleanup(const char *xlog)
{
char archiveStatusPath[MAXPGPATH];
/* Remove the .done file */
StatusFilePath(archiveStatusPath, xlog, ".done");
unlink(archiveStatusPath);
/* should we complain about failure? */
/* Remove the .ready file if present --- normally it shouldn't be */
StatusFilePath(archiveStatusPath, xlog, ".ready");
unlink(archiveStatusPath);
/* should we complain about failure? */
}

23
src/include/access/timeline.h
Unescape View File

@ -0,0 +1,23 @@
/*
* timeline.h
*
* Functions for reading and writing timeline history files.
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/access/timeline.h
*/
#ifndef TIMELINE_H
#define TIMELINE_H
#include "access/xlogdefs.h"
#include "nodes/pg_list.h"
extern List *readTimeLineHistory(TimeLineID targetTLI);
extern bool existsTimeLineHistory(TimeLineID probeTLI);
extern TimeLineID findNewestTimeLine(TimeLineID startTLI);
extern void writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
TimeLineID endTLI, XLogSegNo endLogSegNo, char *reason);
#endif /* TIMELINE_H */

23
src/include/access/xlog_internal.h
Unescape View File

@ -229,6 +229,29 @@ extern const RmgrData RmgrTable[];
extern pg_time_t GetLastSegSwitchTime(void);
extern XLogRecPtr RequestXLogSwitch(void);
extern void GetOldestRestartPoint(XLogRecPtr *oldrecptr, TimeLineID *oldtli);
/*
* Exported for the functions in timeline.c and xlogarchive.c. Only valid
* in the startup process.
*/
extern bool InArchiveRecovery;
extern bool StandbyMode;
extern char *recoveryRestoreCommand;
/*
* Prototypes for functions in xlogarchive.c
*/
extern bool RestoreArchivedFile(char *path, const char *xlogfname,
const char *recovername, off_t expectedSize);
extern void ExecuteRecoveryCommand(char *command, char *commandName,
bool failOnerror);
extern void XLogArchiveNotify(const char *xlog);
extern void XLogArchiveNotifySeg(XLogSegNo segno);
extern bool XLogArchiveCheckDone(const char *xlog);
extern bool XLogArchiveIsBusy(const char *xlog);
extern void XLogArchiveCleanup(const char *xlog);
/*
* These aren't in xlog.h because I'd rather not include fmgr.h there.
*/

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