Change the relation_open protocol so that we obtain lock on a relation

(table or index) before trying to open its relcache entry.  This fixes
race conditions in which someone else commits a change to the relation's
catalog entries while we are in process of doing relcache load.  Problems
of that ilk have been reported sporadically for years, but it was not
really practical to fix until recently --- for instance, the recent
addition of WAL-log support for in-place updates helped.

Along the way, remove pg_am.amconcurrent: all AMs are now expected to support
concurrent update.

9 files changed, 46 insertions, 48 deletions

diff --git a/src/include/access/genam.h b/src/include/access/genam.h
index 9cd9162c26..ddad174527 100644
--- a/src/include/access/genam.h
+++ b/src/include/access/genam.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.64 2006/07/13 17:47:01 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/genam.h,v 1.65 2006/07/31 20:09:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,6 +17,7 @@
 #include "access/relscan.h"
 #include "access/sdir.h"
 #include "nodes/primnodes.h"
+#include "storage/lock.h"
 
 /*
  * Struct for statistics returned by ambuild
@@ -84,9 +85,9 @@ typedef SysScanDescData *SysScanDesc;
 /*
  * generalized index_ interface routines (in indexam.c)
  */
-extern Relation index_open(Oid relationId);
-extern Relation index_openrv(const RangeVar *relation);
-extern void index_close(Relation relation);
+extern Relation index_open(Oid relationId, LOCKMODE lockmode);
+extern void index_close(Relation relation, LOCKMODE lockmode);
+
 extern bool index_insert(Relation indexRelation,
 			 Datum *values, bool *isnull,
 			 ItemPointer heap_t_ctid,
@@ -95,11 +96,9 @@ extern bool index_insert(Relation indexRelation,
 
 extern IndexScanDesc index_beginscan(Relation heapRelation,
 				Relation indexRelation,
-				bool need_index_lock,
 				Snapshot snapshot,
 				int nkeys, ScanKey key);
 extern IndexScanDesc index_beginscan_multi(Relation indexRelation,
-					  bool need_index_lock,
 					  Snapshot snapshot,
 					  int nkeys, ScanKey key);
 extern void index_rescan(IndexScanDesc scan, ScanKey key);
diff --git a/src/include/access/relscan.h b/src/include/access/relscan.h
index cbe7b0c244..d32ab6d524 100644
--- a/src/include/access/relscan.h
+++ b/src/include/access/relscan.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/relscan.h,v 1.48 2006/07/13 18:01:01 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/relscan.h,v 1.49 2006/07/31 20:09:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -62,7 +62,6 @@ typedef struct IndexScanDescData
 	int			numberOfKeys;	/* number of scan keys */
 	ScanKey		keyData;		/* array of scan key descriptors */
 	bool		is_multiscan;	/* TRUE = using amgetmulti */
-	bool		have_lock;		/* TRUE = holding AccessShareLock for scan */
 
 	/* signaling to index AM about killing index tuples */
 	bool		kill_prior_tuple;		/* last-returned tuple is dead */
diff --git a/src/include/catalog/catalog.h b/src/include/catalog/catalog.h
index 6136a33f24..512ea9adbf 100644
--- a/src/include/catalog/catalog.h
+++ b/src/include/catalog/catalog.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catalog.h,v 1.35 2006/03/05 15:58:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catalog.h,v 1.36 2006/07/31 20:09:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -31,6 +31,8 @@ extern bool IsToastNamespace(Oid namespaceId);
 
 extern bool IsReservedName(const char *name);
 
+extern bool IsSharedRelation(Oid relationId);
+
 extern Oid	GetNewOid(Relation relation);
 extern Oid	GetNewOidWithIndex(Relation relation, Relation indexrel);
 extern Oid GetNewRelFileNode(Oid reltablespace, bool relisshared,
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 052d2a19cf..23b0ac9ce4 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.344 2006/07/31 01:16:37 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.345 2006/07/31 20:09:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200607301
+#define CATALOG_VERSION_NO	200607311
 
 #endif
diff --git a/src/include/catalog/pg_am.h b/src/include/catalog/pg_am.h
index 048e3e97f7..7b155bf828 100644
--- a/src/include/catalog/pg_am.h
+++ b/src/include/catalog/pg_am.h
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_am.h,v 1.45 2006/07/03 22:45:40 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_am.h,v 1.46 2006/07/31 20:09:05 tgl Exp $
  *
  * NOTES
  *		the genbki.sh script reads this file and generates .bki
@@ -51,7 +51,6 @@ CATALOG(pg_am,2601)
 	bool		amoptionalkey;	/* can query omit key for the first column? */
 	bool		amindexnulls;	/* does AM support NULL index entries? */
 	bool		amstorage;		/* can storage type differ from column type? */
-	bool		amconcurrent;	/* does AM support concurrent updates? */
 	bool		amclusterable;	/* does AM support cluster command? */
 	regproc		aminsert;		/* "insert this tuple" function */
 	regproc		ambeginscan;	/* "start new scan" function */
@@ -79,7 +78,7 @@ typedef FormData_pg_am *Form_pg_am;
  *		compiler constants for pg_am
  * ----------------
  */
-#define Natts_pg_am						24
+#define Natts_pg_am						23
 #define Anum_pg_am_amname				1
 #define Anum_pg_am_amstrategies			2
 #define Anum_pg_am_amsupport			3
@@ -89,37 +88,36 @@ typedef FormData_pg_am *Form_pg_am;
 #define Anum_pg_am_amoptionalkey		7
 #define Anum_pg_am_amindexnulls			8
 #define Anum_pg_am_amstorage			9
-#define Anum_pg_am_amconcurrent			10
-#define Anum_pg_am_amclusterable		11
-#define Anum_pg_am_aminsert				12
-#define Anum_pg_am_ambeginscan			13
-#define Anum_pg_am_amgettuple			14
-#define Anum_pg_am_amgetmulti			15
-#define Anum_pg_am_amrescan				16
-#define Anum_pg_am_amendscan			17
-#define Anum_pg_am_ammarkpos			18
-#define Anum_pg_am_amrestrpos			19
-#define Anum_pg_am_ambuild				20
-#define Anum_pg_am_ambulkdelete			21
-#define Anum_pg_am_amvacuumcleanup		22
-#define Anum_pg_am_amcostestimate		23
-#define Anum_pg_am_amoptions			24
+#define Anum_pg_am_amclusterable		10
+#define Anum_pg_am_aminsert				11
+#define Anum_pg_am_ambeginscan			12
+#define Anum_pg_am_amgettuple			13
+#define Anum_pg_am_amgetmulti			14
+#define Anum_pg_am_amrescan				15
+#define Anum_pg_am_amendscan			16
+#define Anum_pg_am_ammarkpos			17
+#define Anum_pg_am_amrestrpos			18
+#define Anum_pg_am_ambuild				19
+#define Anum_pg_am_ambulkdelete			20
+#define Anum_pg_am_amvacuumcleanup		21
+#define Anum_pg_am_amcostestimate		22
+#define Anum_pg_am_amoptions			23
 
 /* ----------------
  *		initial contents of pg_am
  * ----------------
  */
 
-DATA(insert OID = 403 (  btree	5 1 1 t t t t f t t btinsert btbeginscan btgettuple btgetmulti btrescan btendscan btmarkpos btrestrpos btbuild btbulkdelete btvacuumcleanup btcostestimate btoptions ));
+DATA(insert OID = 403 (  btree	5 1 1 t t t t f t btinsert btbeginscan btgettuple btgetmulti btrescan btendscan btmarkpos btrestrpos btbuild btbulkdelete btvacuumcleanup btcostestimate btoptions ));
 DESCR("b-tree index access method");
 #define BTREE_AM_OID 403
-DATA(insert OID = 405 (  hash	1 1 0 f f f f f t f hashinsert hashbeginscan hashgettuple hashgetmulti hashrescan hashendscan hashmarkpos hashrestrpos hashbuild hashbulkdelete hashvacuumcleanup hashcostestimate hashoptions ));
+DATA(insert OID = 405 (  hash	1 1 0 f f f f f f hashinsert hashbeginscan hashgettuple hashgetmulti hashrescan hashendscan hashmarkpos hashrestrpos hashbuild hashbulkdelete hashvacuumcleanup hashcostestimate hashoptions ));
 DESCR("hash index access method");
 #define HASH_AM_OID 405
-DATA(insert OID = 783 (  gist	100 7 0 f t t t t t t gistinsert gistbeginscan gistgettuple gistgetmulti gistrescan gistendscan gistmarkpos gistrestrpos gistbuild gistbulkdelete gistvacuumcleanup gistcostestimate gistoptions ));
+DATA(insert OID = 783 (  gist	100 7 0 f t t t t t gistinsert gistbeginscan gistgettuple gistgetmulti gistrescan gistendscan gistmarkpos gistrestrpos gistbuild gistbulkdelete gistvacuumcleanup gistcostestimate gistoptions ));
 DESCR("GiST index access method");
 #define GIST_AM_OID 783
-DATA(insert OID = 2742 (  gin	100 4 0 f f f f t t f gininsert ginbeginscan gingettuple gingetmulti ginrescan ginendscan ginmarkpos ginrestrpos ginbuild ginbulkdelete ginvacuumcleanup gincostestimate ginoptions ));
+DATA(insert OID = 2742 (  gin	100 4 0 f f f f t f gininsert ginbeginscan gingettuple gingetmulti ginrescan ginendscan ginmarkpos ginrestrpos ginbuild ginbulkdelete ginvacuumcleanup gincostestimate ginoptions ));
 DESCR("GIN index access method");
 #define GIN_AM_OID 2742
 
diff --git a/src/include/optimizer/plancat.h b/src/include/optimizer/plancat.h
index c0e86cb80e..322ae97741 100644
--- a/src/include/optimizer/plancat.h
+++ b/src/include/optimizer/plancat.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/plancat.h,v 1.39 2006/03/05 15:58:57 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/plancat.h,v 1.40 2006/07/31 20:09:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,7 +17,7 @@
 #include "nodes/relation.h"
 
 
-extern void get_relation_info(Oid relationObjectId, RelOptInfo *rel);
+extern void get_relation_info(PlannerInfo *root, Oid relationObjectId, RelOptInfo *rel);
 
 extern bool relation_excluded_by_constraints(RelOptInfo *rel,
 											 RangeTblEntry *rte);
diff --git a/src/include/storage/lmgr.h b/src/include/storage/lmgr.h
index 1eaede10a0..d0f9ba2b9c 100644
--- a/src/include/storage/lmgr.h
+++ b/src/include/storage/lmgr.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.54 2006/03/05 15:58:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lmgr.h,v 1.55 2006/07/31 20:09:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -21,13 +21,16 @@
 extern void RelationInitLockInfo(Relation relation);
 
 /* Lock a relation */
+extern void LockRelationOid(Oid relid, LOCKMODE lockmode);
+extern bool ConditionalLockRelationOid(Oid relid, LOCKMODE lockmode);
+extern void UnlockRelationId(LockRelId *relid, LOCKMODE lockmode);
+
 extern void LockRelation(Relation relation, LOCKMODE lockmode);
 extern bool ConditionalLockRelation(Relation relation, LOCKMODE lockmode);
 extern void UnlockRelation(Relation relation, LOCKMODE lockmode);
 
-extern void LockRelationForSession(LockRelId *relid, bool istemprel,
-					   LOCKMODE lockmode);
-extern void UnlockRelationForSession(LockRelId *relid, LOCKMODE lockmode);
+extern void LockRelationIdForSession(LockRelId *relid, LOCKMODE lockmode);
+extern void UnlockRelationIdForSession(LockRelId *relid, LOCKMODE lockmode);
 
 /* Lock a relation for extension */
 extern void LockRelationForExtension(Relation relation, LOCKMODE lockmode);
@@ -62,4 +65,7 @@ extern void LockSharedObject(Oid classid, Oid objid, uint16 objsubid,
 extern void UnlockSharedObject(Oid classid, Oid objid, uint16 objsubid,
 				   LOCKMODE lockmode);
 
+/* Knowledge about which locktags describe temp objects */
+extern bool LockTagIsTemp(const LOCKTAG *tag);
+
 #endif   /* LMGR_H */
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index 7a2651cd28..208b4a93cc 100644
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.96 2006/07/23 23:08:46 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.97 2006/07/31 20:09:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -349,7 +349,6 @@ typedef struct LOCALLOCK
 	/* data */
 	LOCK	   *lock;			/* associated LOCK object in shared mem */
 	PROCLOCK   *proclock;		/* associated PROCLOCK object in shmem */
-	bool		isTempObject;	/* true if lock is on a temporary object */
 	uint32		hashcode;		/* copy of LOCKTAG's hash value */
 	int			nLocks;			/* total number of times lock is held */
 	int			numLockOwners;	/* # of relevant ResourceOwners */
@@ -405,7 +404,6 @@ extern void InitLocks(void);
 extern LockMethod GetLocksMethodTable(const LOCK *lock);
 extern uint32 LockTagHashCode(const LOCKTAG *locktag);
 extern LockAcquireResult LockAcquire(const LOCKTAG *locktag,
-			bool isTempObject,
 			LOCKMODE lockmode,
 			bool sessionLock,
 			bool dontWait);
diff --git a/src/include/utils/relcache.h b/src/include/utils/relcache.h
index b30387a7ef..aa2b1608c1 100644
--- a/src/include/utils/relcache.h
+++ b/src/include/utils/relcache.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/relcache.h,v 1.54 2006/05/04 18:51:36 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/relcache.h,v 1.55 2006/07/31 20:09:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,13 +17,9 @@
 #include "utils/rel.h"
 
 /*
- * relation lookup routines
+ * Routines to open (lookup) and close a relcache entry
  */
 extern Relation RelationIdGetRelation(Oid relationId);
-
-/* finds an existing cache entry, but won't make a new one */
-extern Relation RelationIdCacheGetRelation(Oid relationId);
-
 extern void RelationClose(Relation relation);
 
 /*