Restructure pg_opclass, pg_amop, and pg_amproc per previous discussions in

pgsql-hackers.  pg_opclass now has a row for each opclass supported by each
index AM, not a row for each opclass name.  This allows pg_opclass to show
directly whether an AM supports an opclass, and furthermore makes it possible
to store additional information about an opclass that might be AM-dependent.
pg_opclass and pg_amop now store "lossy" and "haskeytype" information that we
previously expected the user to remember to provide in CREATE INDEX commands.
Lossiness is no longer an index-level property, but is associated with the
use of a particular operator in a particular index opclass.

Along the way, IndexSupportInitialize now uses the syscaches to retrieve
pg_amop and pg_amproc entries.  I find this reduces backend launch time by
about ten percent, at the cost of a couple more special cases in catcache.c's
IndexScanOK.

Initial work by Oleg Bartunov and Teodor Sigaev, further hacking by Tom Lane.

initdb forced.

src/backend/utils/cache/catcache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.81 2001/06/22 19:16:23 wieck Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/catcache.c,v 1.82 2001/08/21 16:36:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,6 +18,7 @@
 #include "access/hash.h"
 #include "access/heapam.h"
 #include "access/valid.h"
+#include "catalog/pg_opclass.h"
 #include "catalog/pg_operator.h"
 #include "catalog/pg_type.h"
 #include "catalog/catname.h"
@@ -812,7 +813,7 @@ IndexScanOK(CatCache *cache, ScanKey cur_skey)
 			sd = heap_beginscan(rel, false, SnapshotNow, 1, &key);
 			ntp = heap_getnext(sd, 0);
 			if (!HeapTupleIsValid(ntp))
-				elog(ERROR, "SearchSelfReferences: %s not found in %s",
+				elog(ERROR, "IndexScanOK: %s not found in %s",
 					 IndexRelidIndex, RelationRelationName);
 			indexSelfOid = ntp->t_data->t_oid;
 			heap_endscan(sd);
@@ -823,6 +824,16 @@ IndexScanOK(CatCache *cache, ScanKey cur_skey)
 		if (DatumGetObjectId(cur_skey[0].sk_argument) == indexSelfOid)
 			return false;
 	}
+	else if (cache->id == AMOPSTRATEGY ||
+			 cache->id == AMPROCNUM)
+	{
+		/* Looking for an OID or INT2 btree operator or function? */
+		Oid			lookup_oid = DatumGetObjectId(cur_skey[0].sk_argument);
+
+		if (lookup_oid == OID_BTREE_OPS_OID ||
+			lookup_oid == INT2_BTREE_OPS_OID)
+			return false;
+	}
 	else if (cache->id == OPEROID)
 	{
 		/* Looking for an OID comparison function? */
@@ -858,7 +869,7 @@ SearchCatCache(CatCache *cache,
 	MemoryContext oldcxt;
 
 	/*
-	 * one-time startup overhead
+	 * one-time startup overhead for each cache
 	 */
 	if (cache->cc_tupdesc == NULL)
 		CatalogCacheInitializeCache(cache);

src/backend/utils/cache/lsyscache.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.56 2001/06/14 01:09:22 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.57 2001/08/21 16:36:05 tgl Exp $
  *
  * NOTES
  *	  Eventually, the index information should go through here, too.
@@ -16,6 +16,8 @@
 #include "postgres.h"
 
 #include "access/tupmacs.h"
+#include "catalog/pg_amop.h"
+#include "catalog/pg_opclass.h"
 #include "catalog/pg_operator.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_shadow.h"
@@ -30,19 +32,48 @@
 /*				---------- AMOP CACHES ----------						 */
 
 /*
- * op_class
+ * op_in_opclass
  *
- *		Return t iff operator 'opno' is in operator class 'opclass' for
- *		access method 'amopid'.
+ *		Return t iff operator 'opno' is in operator class 'opclass'.
  */
 bool
-op_class(Oid opno, Oid opclass, Oid amopid)
+op_in_opclass(Oid opno, Oid opclass)
 {
 	return SearchSysCacheExists(AMOPOPID,
 								ObjectIdGetDatum(opclass),
 								ObjectIdGetDatum(opno),
-								ObjectIdGetDatum(amopid),
-								0);
+								0, 0);
+}
+
+/*
+ * op_requires_recheck
+ *
+ *		Return t if operator 'opno' requires a recheck when used as a
+ *		member of opclass 'opclass' (ie, this opclass is lossy for this
+ *		operator).
+ *
+ * Caller should already have verified that opno is a member of opclass,
+ * therefore we raise an error if the tuple is not found.
+ */
+bool
+op_requires_recheck(Oid opno, Oid opclass)
+{
+	HeapTuple	tp;
+	Form_pg_amop amop_tup;
+	bool		result;
+
+	tp = SearchSysCache(AMOPOPID,
+						ObjectIdGetDatum(opclass),
+						ObjectIdGetDatum(opno),
+						0, 0);
+	if (!HeapTupleIsValid(tp))
+		elog(ERROR, "op_requires_recheck: op %u is not a member of opclass %u",
+			 opno, opclass);
+	amop_tup = (Form_pg_amop) GETSTRUCT(tp);
+
+	result = amop_tup->amopreqcheck;
+	ReleaseSysCache(tp);
+	return result;
 }
 
 /*				---------- ATTRIBUTE CACHES ----------					 */
@@ -222,6 +253,33 @@ get_atttypetypmod(Oid relid, AttrNumber attnum,
 /*		watch this space...
  */
 
+/*				---------- OPCLASS CACHE ----------						 */
+
+/*
+ * opclass_is_btree
+ *
+ *		Returns TRUE iff the specified opclass is associated with the
+ *		btree index access method.
+ */
+bool
+opclass_is_btree(Oid opclass)
+{
+	HeapTuple	tp;
+	Form_pg_opclass cla_tup;
+	bool		result;
+
+	tp = SearchSysCache(CLAOID,
+						ObjectIdGetDatum(opclass),
+						0, 0, 0);
+	if (!HeapTupleIsValid(tp))
+		elog(ERROR, "cache lookup failed for opclass %u", opclass);
+	cla_tup = (Form_pg_opclass) GETSTRUCT(tp);
+
+	result = (cla_tup->opcamid == BTREE_AM_OID);
+	ReleaseSysCache(tp);
+	return result;
+}
+
 /*				---------- OPERATOR CACHE ----------					 */
 
 /*

src/backend/utils/cache/syscache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/syscache.c,v 1.64 2001/08/10 18:57:37 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/syscache.c,v 1.65 2001/08/21 16:36:05 tgl Exp $
  *
  * NOTES
  *	  These routines allow the parser/planner/executor to perform
@@ -27,6 +27,7 @@
 #include "catalog/indexing.h"
 #include "catalog/pg_aggregate.h"
 #include "catalog/pg_amop.h"
+#include "catalog/pg_amproc.h"
 #include "catalog/pg_group.h"
 #include "catalog/pg_index.h"
 #include "catalog/pg_inherits.h"
@@ -113,23 +114,33 @@ static struct cachedesc cacheinfo[] = {
 			0
 	}},
 	{AccessMethodOperatorRelationName,	/* AMOPOPID */
-		AccessMethodOpidIndex,
+		AccessMethodOperatorIndex,
 		0,
-		3,
+		2,
 		{
 			Anum_pg_amop_amopclaid,
 			Anum_pg_amop_amopopr,
-			Anum_pg_amop_amopid,
+			0,
 			0
 	}},
 	{AccessMethodOperatorRelationName,	/* AMOPSTRATEGY */
 		AccessMethodStrategyIndex,
 		0,
-		3,
+		2,
 		{
-			Anum_pg_amop_amopid,
 			Anum_pg_amop_amopclaid,
 			Anum_pg_amop_amopstrategy,
+			0,
+			0
+	}},
+	{AccessMethodProcedureRelationName,	/* AMPROCNUM */
+		AccessMethodProcedureIndex,
+		0,
+		2,
+		{
+			Anum_pg_amproc_amopclaid,
+			Anum_pg_amproc_amprocnum,
+			0,
 			0
 	}},
 	{AttributeRelationName,		/* ATTNAME */
@@ -152,22 +163,22 @@ static struct cachedesc cacheinfo[] = {
 			0,
 			0
 	}},
-	{OperatorClassRelationName, /* CLADEFTYPE */
-		OpclassDeftypeIndex,
+	{OperatorClassRelationName, /* CLAAMNAME */
+		OpclassAmNameIndex,
 		0,
-		1,
+		2,
 		{
-			Anum_pg_opclass_opcdeftype,
-			0,
+			Anum_pg_opclass_opcamid,
+			Anum_pg_opclass_opcname,
 			0,
 			0
 	}},
-	{OperatorClassRelationName, /* CLANAME */
-		OpclassNameIndex,
+	{OperatorClassRelationName, /* CLAOID */
+		OpclassOidIndex,
 		0,
 		1,
 		{
-			Anum_pg_opclass_opcname,
+			ObjectIdAttributeNumber,
 			0,
 			0,
 			0