Fix problems seen in parallel regress tests when SI buffer overruns (causing

syscache and relcache flushes).  Relcache entry rebuild now preserves
original tupledesc, rewrite rules, and triggers if possible, so that pointers
to these things remain valid --- if these things change while relcache entry
has positive refcount, we elog(ERROR) to avoid later crash.  Arrange for
xact-local rels to be rebuilt when an SI inval message is seen for them,
so that they are updated by CommandCounterIncrement the same as regular rels.
(This is useful because of Hiroshi's recent changes to process our own SI
messages at CommandCounterIncrement time.)  This allows simplification of
some routines that previously hacked around the lack of an automatic update.
catcache now keeps its own copy of tupledesc for its relation, rather than
depending on the relcache's copy; this avoids needing to reinitialize catcache
during a cache flush, which saves some cycles and eliminates nasty circularity
problems that occur if a cache flush happens while trying to initialize a
catcache.
Eliminate a number of permanent memory leaks that used to happen during
catcache or relcache flush; not least of which was that catcache never
freed any cached tuples!  (Rule parsetree storage is still leaked, however;
will fix that separately.)
Nothing done yet about code that uses tuples retrieved by SearchSysCache
for longer than is safe.

src/backend/catalog/heap.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.119 2000/01/26 05:56:10 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.120 2000/01/31 04:35:48 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -2098,18 +2098,6 @@ AddRelationRawConstraints(Relation rel,
 
 	heap_close(relrel, RowExclusiveLock);
 	heap_freetuple(reltup);
-
-	/*
-	 * Force rebuild of our own relcache entry, otherwise subsequent commands
-	 * in this transaction won't see the new defaults/constraints.
-	 * Must bump command counter or relcache rebuild won't see 'em either.
-	 *
-	 * (This might seem unnecessary, since we are sending out an SI message;
-	 * but if the relation has just been created then relcache.c will ignore
-	 * the SI message on the grounds that the rel is transaction-local...)
-	 */
-	CommandCounterIncrement();
-	RelationRebuildRelation(rel);
 }
 
 static void