Only recycle normal files in pg_xlog as WAL segments. pg_standby creates

symbolic links with the -l option, and as Fujii Masao pointed out we ended up
overwriting files in the archive directory before this patch. Patch by
Aidan Van Dyk, Fujii Masao and me.

Backpatch to 8.3, where pg_standby was introduced.

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 64e8ead74c1f7bd831980a3a72075adc567c7dce..645baed4b62f17d5c6b0e290e592c541e851e239 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -3006,6 +3006,7 @@ RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr)
        struct dirent *xlde;
        char            lastoff[MAXFNAMELEN];
        char            path[MAXPGPATH];
+       struct stat statbuf;
 
        /*
         * Initialize info about where to try to recycle to.  We allow recycling
@@ -3046,11 +3047,13 @@ RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr)
 
                                /*
                                 * Before deleting the file, see if it can be recycled as a
-                                * future log segment.
+                                * future log segment. Only recycle normal files, pg_standby
+                                * for example can create symbolic links pointing to a
+                                * separate archive directory.
                                 */
-                               if (InstallXLogFileSegment(&endlogId, &endlogSeg, path,
-                                                                                  true, &max_advance,
-                                                                                  true))
+                               if (lstat(path, &statbuf) == 0 && S_ISREG(statbuf.st_mode) &&
+                                       InstallXLogFileSegment(&endlogId, &endlogSeg, path,
+                                                                                  true, &max_advance, true))
                                {
                                        ereport(DEBUG2,
                                                        (errmsg("recycled transaction log file \"%s\"",