Create a "relation mapping" infrastructure to support changing the relfilenodes

of shared or nailed system catalogs.  This has two key benefits:

* The new CLUSTER-based VACUUM FULL can be applied safely to all catalogs.

* We no longer have to use an unsafe reindex-in-place approach for reindexing
  shared catalogs.

CLUSTER on nailed catalogs now works too, although I left it disabled on
shared catalogs because the resulting pg_index.indisclustered update would
only be visible in one database.

Since reindexing shared system catalogs is now fully transactional and
crash-safe, the former special cases in REINDEX behavior have been removed;
shared catalogs are treated the same as non-shared.

This commit does not do anything about the recently-discussed problem of
deadlocks between VACUUM FULL/CLUSTER on a system catalog and other
concurrent queries; will address that in a separate patch.  As a stopgap,
parallel_schedule has been tweaked to run vacuum.sql by itself, to avoid
such failures during the regression tests.

2 files changed, 30 insertions, 6 deletions

diff --git a/src/backend/bootstrap/bootparse.y b/src/backend/bootstrap/bootparse.y
index a6c1243b958..9cc68501ffc 100644
--- a/src/backend/bootstrap/bootparse.y
+++ b/src/backend/bootstrap/bootparse.y
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.104 2010/01/28 23:21:11 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.105 2010/02/07 20:48:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -185,11 +185,26 @@ Boot_CreateStmt:
 		  RPAREN
 				{
 					TupleDesc tupdesc;
+					bool	shared_relation;
+					bool	mapped_relation;
 
 					do_start();
 
 					tupdesc = CreateTupleDesc(numattr, !($6), attrtypes);
 
+					shared_relation = $5;
+
+					/*
+					 * The catalogs that use the relation mapper are the
+					 * bootstrap catalogs plus the shared catalogs.  If this
+					 * ever gets more complicated, we should invent a BKI
+					 * keyword to mark the mapped catalogs, but for now a
+					 * quick hack seems the most appropriate thing.  Note in
+					 * particular that all "nailed" heap rels (see formrdesc
+					 * in relcache.c) must be mapped.
+					 */
+					mapped_relation = ($4 || shared_relation);
+
 					if ($4)
 					{
 						if (boot_reldesc)
@@ -200,11 +215,12 @@ Boot_CreateStmt:
 
 						boot_reldesc = heap_create($2,
 												   PG_CATALOG_NAMESPACE,
-												   $5 ? GLOBALTABLESPACE_OID : 0,
+												   shared_relation ? GLOBALTABLESPACE_OID : 0,
 												   $3,
 												   tupdesc,
 												   RELKIND_RELATION,
-												   $5,
+												   shared_relation,
+												   mapped_relation,
 												   true);
 						elog(DEBUG4, "bootstrap relation created");
 					}
@@ -214,7 +230,7 @@ Boot_CreateStmt:
 
 						id = heap_create_with_catalog($2,
 													  PG_CATALOG_NAMESPACE,
-													  $5 ? GLOBALTABLESPACE_OID : 0,
+													  shared_relation ? GLOBALTABLESPACE_OID : 0,
 													  $3,
 													  $7,
 													  InvalidOid,
@@ -222,7 +238,8 @@ Boot_CreateStmt:
 													  tupdesc,
 													  NIL,
 													  RELKIND_RELATION,
-													  $5,
+													  shared_relation,
+													  mapped_relation,
 													  true,
 													  0,
 													  ONCOMMIT_NOOP,
diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 14e4b839e44..d2b7c1e5854 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.258 2010/01/22 16:40:18 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootstrap.c,v 1.259 2010/02/07 20:48:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,6 +42,7 @@
 #include "utils/fmgroids.h"
 #include "utils/memutils.h"
 #include "utils/ps_status.h"
+#include "utils/relmapper.h"
 #include "utils/tqual.h"
 
 extern int	optind;
@@ -491,6 +492,12 @@ BootstrapModeMain(void)
 	 */
 	boot_yyparse();
 
+	/*
+	 * We should now know about all mapped relations, so it's okay to
+	 * write out the initial relation mapping files.
+	 */
+	RelationMapFinishBootstrap();
+
 	/* Perform a checkpoint to ensure everything's down to disk */
 	SetProcessingMode(NormalProcessing);
 	CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN | CHECKPOINT_IMMEDIATE);