/*
* 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;
}
/*
* Convenience routine to notify using segment number representation of filename
*/
void
XLogArchiveNotifySeg(XLogSegNo segno)
{
char xlog[MAXFNAMELEN];
XLogFileName(xlog, ThisTimeLineID, segno);
XLogArchiveNotify(xlog);
}
/*
* A file was restored from the archive under a temporary filename (path),
* and now we want to keep it. Rename it under the permanent filename in
* in pg_xlog (xlogfname), replacing any existing file with the same name.
*/
void
KeepFileRestoredFromArchive(char *path, char *xlogfname)
{
char xlogfpath[MAXPGPATH];
bool reload = false;
struct stat statbuf;
snprintf(xlogfpath, MAXPGPATH, XLOGDIR "/%s", xlogfname);
if (stat(xlogfpath, &statbuf) == 0)
{
char oldpath[MAXPGPATH];
#ifdef WIN32
static unsigned int deletedcounter = 1;
/*
* On Windows, if another process (e.g a walsender process) holds the
* file open in FILE_SHARE_DELETE mode, unlink will succeed, but the
* file will still show up in directory listing until the last handle
* is closed, and we cannot rename the new file in its place until
* that. To avoid that problem, rename the old file to a temporary
* name first. Use a counter to create a unique filename, because the
* same file might be restored from the archive multiple times, and a
* walsender could still be holding onto an old deleted version of it.
*/
snprintf(oldpath, MAXPGPATH, "%s.deleted%u",
xlogfpath, deletedcounter++);
if (rename(xlogfpath, oldpath) != 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename file \"%s\" to \"%s\": %m",
xlogfpath, oldpath)));
}
#else
/* same-size buffers, so this never truncates */
strlcpy(oldpath, xlogfpath, MAXPGPATH);
#endif
if (unlink(oldpath) != 0)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not remove file \"%s\": %m",
xlogfpath)));
reload = true;
}
if (rename(path, xlogfpath) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename file \"%s\" to \"%s\": %m",
path, xlogfpath)));
/*
* Create .done file forcibly to prevent the restored segment from being
* archived again later.
*/
if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS)
XLogArchiveForceDone(xlogfname);
else
XLogArchiveNotify(xlogfname);
/*
* If the existing file was replaced, since walsenders might have it open,
* request them to reload a currently-open segment. This is only required
* for WAL segments, walsenders don't hold other files open, but there's
* no harm in doing this too often, and we don't know what kind of a file
* we're dealing with here.
*/
if (reload)
WalSndRqstFileReload();
/*
* Signal walsender that new WAL has arrived. Again, this isn't necessary
* if we restored something other than a WAL segment, but it does no harm
* either.
*/
WalSndWakeup();
}