Repair assert failure in tuple-chain-moving logic (introduced by yours

truly, I'm afraid).

diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 32e72c4316e797748683ec7c287a8401d3d4e6c5..c8498eddbce69de17969580fa8a19555b7284c26 100644 (file)
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.144 2000/03/17 02:36:06 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.145 2000/04/06 00:29:51 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1510,6 +1510,8 @@ vc_repair_frag(VRelStats *vacrelstats, Relation onerel,
                                ItemPointerSetInvalid(&Ctid);
                                for (ti = 0; ti < num_vtmove; ti++)
                                {
+                                       VPageDescr      destvpd = vtmove[ti].vpd;
+
                                        /* Get tuple from chain */
                                        tuple.t_self = vtmove[ti].tid;
                                        Cbuf = ReadBuffer(onerel,
@@ -1521,7 +1523,7 @@ vc_repair_frag(VRelStats *vacrelstats, Relation onerel,
                                        tuple.t_data = (HeapTupleHeader) PageGetItem(Cpage, Citemid);
                                        tuple_len = tuple.t_len = ItemIdGetLength(Citemid);
                                        /* Get page to move in */
-                                       cur_buffer = ReadBuffer(onerel, vtmove[ti].vpd->vpd_blkno);
+                                       cur_buffer = ReadBuffer(onerel, destvpd->vpd_blkno);
 
                                        /*
                                         * We should LockBuffer(cur_buffer) but don't, at the
@@ -1530,9 +1532,24 @@ vc_repair_frag(VRelStats *vacrelstats, Relation onerel,
                                         * to get t_infomask of inserted heap tuple !!!
                                         */
                                        ToPage = BufferGetPage(cur_buffer);
-                                       /* if this page was not used before - clean it */
+                                       /*
+                                        * If this page was not used before - clean it.
+                                        *
+                                        * This path is different from the other callers of
+                                        * vc_vacpage, because we have already incremented the
+                                        * vpd's vpd_offsets_used field to account for the
+                                        * tuple(s) we expect to move onto the page.  Therefore
+                                        * vc_vacpage's check for vpd_offsets_used == 0 is wrong.
+                                        * But since that's a good debugging check for all other
+                                        * callers, we work around it here rather than remove it.
+                                        */
                                        if (!PageIsEmpty(ToPage) && vtmove[ti].cleanVpd)
-                                               vc_vacpage(ToPage, vtmove[ti].vpd);
+                                       {
+                                               int sv_offsets_used = destvpd->vpd_offsets_used;
+                                               destvpd->vpd_offsets_used = 0;
+                                               vc_vacpage(ToPage, destvpd);
+                                               destvpd->vpd_offsets_used = sv_offsets_used;
+                                       }
                                        heap_copytuple_with_tuple(&tuple, &newtup);
                                        RelationInvalidateHeapTuple(onerel, &tuple);
                                        TransactionIdStore(myXID, (TransactionId *) &(newtup.t_data->t_cmin));
@@ -1543,17 +1560,16 @@ vc_repair_frag(VRelStats *vacrelstats, Relation onerel,
                                                                                 InvalidOffsetNumber, LP_USED);
                                        if (newoff == InvalidOffsetNumber)
                                        {
-                                               elog(ERROR, "\
-moving chain: failed to add item with len = %u to page %u",
-                                                        tuple_len, vtmove[ti].vpd->vpd_blkno);
+                                               elog(ERROR, "moving chain: failed to add item with len = %u to page %u",
+                                                        tuple_len, destvpd->vpd_blkno);
                                        }
                                        newitemid = PageGetItemId(ToPage, newoff);
                                        pfree(newtup.t_data);
                                        newtup.t_datamcxt = NULL;
                                        newtup.t_data = (HeapTupleHeader) PageGetItem(ToPage, newitemid);
-                                       ItemPointerSet(&(newtup.t_self), vtmove[ti].vpd->vpd_blkno, newoff);
-                                       if (((int) vtmove[ti].vpd->vpd_blkno) > last_move_dest_block)
-                                               last_move_dest_block = vtmove[ti].vpd->vpd_blkno;
+                                       ItemPointerSet(&(newtup.t_self), destvpd->vpd_blkno, newoff);
+                                       if (((int) destvpd->vpd_blkno) > last_move_dest_block)
+                                               last_move_dest_block = destvpd->vpd_blkno;
 
                                        /*
                                         * Set t_ctid pointing to itself for last tuple in