Prevent the already-archived WAL file from being archived again.

Previously the archive recovery always created .ready file for
the last WAL file of the old timeline at the end of recovery even when
it's restored from the archive and has .done file. That is, there was
the case where the WAL file had both .ready and .done files.
This caused the already-archived WAL file to be archived again.

This commit prevents the archive recovery from creating .ready file
for the last WAL file if it has .done file, in order to prevent it from
being archived again.

This bug was added when cascading replication feature was introduced,
i.e., the commit 5286105800c7d5902f98f32e11b209c471c0c69c.
So, back-patch to 9.2, where cascading replication was added.

Reviewed by Michael Paquier

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index b8ba63d005aa555a127174af46a7c2d3e1d2d5ab..ff1ee8689686ca3f7121a236214c7d8e618fc755 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5786,7 +5786,7 @@ static void
 exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg)
 {
        char            recoveryPath[MAXPGPATH];
-       char            xlogpath[MAXPGPATH];
+       char            xlogfname[MAXFNAMELEN];
 
        /*
         * We are no longer in archive recovery state.
@@ -5814,18 +5814,20 @@ exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg)
         * for the new timeline.
         *
         * Notify the archiver that the last WAL segment of the old timeline is
-        * ready to copy to archival storage. Otherwise, it is not archived for a
-        * while.
+        * 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)
        {
                XLogFileCopy(endLogId, endLogSeg,
                                         endTLI, endLogId, endLogSeg);
 
+               /* Create .ready file only when neither .ready nor .done files exist */
                if (XLogArchivingActive())
                {
-                       XLogFileName(xlogpath, endTLI, endLogId, endLogSeg);
-                       XLogArchiveNotify(xlogpath);
+                       XLogFileName(xlogfname, endTLI, endLogId, endLogSeg);
+                       XLogArchiveCheckDone(xlogfname);
                }
        }
 
@@ -5833,8 +5835,8 @@ exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg)
         * Let's just make real sure there are not .ready or .done flags posted
         * for the new segment.
         */
-       XLogFileName(xlogpath, ThisTimeLineID, endLogId, endLogSeg);
-       XLogArchiveCleanup(xlogpath);
+       XLogFileName(xlogfname, ThisTimeLineID, endLogId, endLogSeg);
+       XLogArchiveCleanup(xlogfname);
 
        /*
         * Since there might be a partial WAL segment named RECOVERYXLOG, get rid