Tweak md.c logic to cope with the situation where WAL replay tries to

write into a high-numbered segment of a relation that was later deleted.
We need to temporarily recreate missing segment files, instead of
failing.

diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 6e7ebed..3bb4a05 100644 (file)
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.111 2004/08/30 02:54:39 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.112 2004/08/30 03:52:43 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -937,10 +937,19 @@ _mdfd_getseg(SMgrRelation reln, BlockNumber blkno, bool allowNotFound)
                         * "target" block.      We should never need to create more than
                         * one new segment per call, so this restriction seems
                         * reasonable.
+                        *
+                        * BUT: when doing WAL recovery, disable this logic and create
+                        * segments unconditionally.  In this case it seems better
+                        * to assume the given blkno is good (it presumably came from
+                        * a CRC-checked WAL record); furthermore this lets us cope
+                        * in the case where we are replaying WAL data that has a write
+                        * into a high-numbered segment of a relation that was later
+                        * deleted.  We want to go ahead and create the segments so
+                        * we can finish out the replay.
                         */
                        v->mdfd_chain = _mdfd_openseg(reln,
                                                                                  nextsegno,
-                                                                                 (segstogo == 1) ? O_CREAT : 0);
+                                                                 (segstogo == 1 || InRecovery) ? O_CREAT : 0);
                        if (v->mdfd_chain == NULL)
                        {
                                if (allowNotFound && errno == ENOENT)