Change gist stratnum function to use CompareType

This changes commit 7406ab623f in that the gist strategy number
mapping support function is changed to use the CompareType enum as
input, instead of the "well-known" RT*StrategyNumber strategy numbers.

This is a bit cleaner, since you are not dealing with two sets of
strategy numbers.  Also, this will enable us to subsume this system
into a more general system of using CompareType to define operator
semantics across index methods.

Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com

contrib/btree_gist/btree_gist--1.7--1.8.sql

@@ -3,85 +3,85 @@
 -- complain if script is sourced in psql, rather than via CREATE EXTENSION
 \echo Use "ALTER EXTENSION btree_gist UPDATE TO '1.8'" to load this file. \quit
 
-CREATE FUNCTION gist_stratnum_btree(smallint)
+CREATE FUNCTION gist_stratnum_btree(int)
 RETURNS smallint
 AS 'MODULE_PATHNAME'
 LANGUAGE C IMMUTABLE PARALLEL SAFE STRICT;
 
 ALTER OPERATOR FAMILY gist_oid_ops USING gist ADD
-	FUNCTION 12 (oid, oid) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (oid, oid) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_int2_ops USING gist ADD
-	FUNCTION 12 (int2, int2) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (int2, int2) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_int4_ops USING gist ADD
-	FUNCTION 12 (int4, int4) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (int4, int4) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_int8_ops USING gist ADD
-	FUNCTION 12 (int8, int8) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (int8, int8) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_float4_ops USING gist ADD
-	FUNCTION 12 (float4, float4) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (float4, float4) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_float8_ops USING gist ADD
-	FUNCTION 12 (float8, float8) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (float8, float8) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_timestamp_ops USING gist ADD
-	FUNCTION 12 (timestamp, timestamp) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (timestamp, timestamp) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_timestamptz_ops USING gist ADD
-	FUNCTION 12 (timestamptz, timestamptz) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (timestamptz, timestamptz) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_time_ops USING gist ADD
-	FUNCTION 12 (time, time) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (time, time) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_date_ops USING gist ADD
-	FUNCTION 12 (date, date) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (date, date) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_interval_ops USING gist ADD
-	FUNCTION 12 (interval, interval) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (interval, interval) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_cash_ops USING gist ADD
-	FUNCTION 12 (money, money) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (money, money) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_macaddr_ops USING gist ADD
-	FUNCTION 12 (macaddr, macaddr) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (macaddr, macaddr) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_text_ops USING gist ADD
-	FUNCTION 12 (text, text) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (text, text) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_bpchar_ops USING gist ADD
-	FUNCTION 12 (bpchar, bpchar) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (bpchar, bpchar) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_bytea_ops USING gist ADD
-	FUNCTION 12 (bytea, bytea) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (bytea, bytea) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_numeric_ops USING gist ADD
-	FUNCTION 12 (numeric, numeric) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (numeric, numeric) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_bit_ops USING gist ADD
-	FUNCTION 12 (bit, bit) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (bit, bit) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_vbit_ops USING gist ADD
-	FUNCTION 12 (varbit, varbit) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (varbit, varbit) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_inet_ops USING gist ADD
-	FUNCTION 12 (inet, inet) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (inet, inet) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_cidr_ops USING gist ADD
-	FUNCTION 12 (cidr, cidr) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (cidr, cidr) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_timetz_ops USING gist ADD
-	FUNCTION 12 (timetz, timetz) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (timetz, timetz) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_uuid_ops USING gist ADD
-	FUNCTION 12 (uuid, uuid) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (uuid, uuid) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_macaddr8_ops USING gist ADD
-	FUNCTION 12 (macaddr8, macaddr8) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (macaddr8, macaddr8) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_enum_ops USING gist ADD
-	FUNCTION 12 (anyenum, anyenum) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (anyenum, anyenum) gist_stratnum_btree (int) ;
 
 ALTER OPERATOR FAMILY gist_bool_ops USING gist ADD
-	FUNCTION 12 (bool, bool) gist_stratnum_btree (int2) ;
+	FUNCTION 12 (bool, bool) gist_stratnum_btree (int) ;

contrib/btree_gist/btree_gist.c

@@ -4,6 +4,7 @@
 #include "postgres.h"
 
 #include "access/stratnum.h"
+#include "nodes/primnodes.h"
 #include "utils/builtins.h"
 
 PG_MODULE_MAGIC;
@@ -60,19 +61,19 @@ gbt_decompress(PG_FUNCTION_ARGS)
 Datum
 gist_stratnum_btree(PG_FUNCTION_ARGS)
 {
-	StrategyNumber strat = PG_GETARG_UINT16(0);
+	CompareType cmptype = PG_GETARG_INT32(0);
 
-	switch (strat)
+	switch (cmptype)
 	{
-		case RTEqualStrategyNumber:
+		case COMPARE_EQ:
 			PG_RETURN_UINT16(BTEqualStrategyNumber);
-		case RTLessStrategyNumber:
+		case COMPARE_LT:
 			PG_RETURN_UINT16(BTLessStrategyNumber);
-		case RTLessEqualStrategyNumber:
+		case COMPARE_LE:
 			PG_RETURN_UINT16(BTLessEqualStrategyNumber);
-		case RTGreaterStrategyNumber:
+		case COMPARE_GT:
 			PG_RETURN_UINT16(BTGreaterStrategyNumber);
-		case RTGreaterEqualStrategyNumber:
+		case COMPARE_GE:
 			PG_RETURN_UINT16(BTGreaterEqualStrategyNumber);
 		default:
 			PG_RETURN_UINT16(InvalidStrategy);

contrib/btree_gist/expected/stratnum.out

@@ -1,11 +1,11 @@
 -- test stratnum support func
-SELECT gist_stratnum_btree(3::smallint);
+SELECT gist_stratnum_btree(7);
  gist_stratnum_btree 
 ---------------------
                    0
 (1 row)
 
-SELECT gist_stratnum_btree(18::smallint);
+SELECT gist_stratnum_btree(3);
  gist_stratnum_btree 
 ---------------------
                    3

contrib/btree_gist/sql/stratnum.sql

@@ -1,3 +1,3 @@
 -- test stratnum support func
-SELECT gist_stratnum_btree(3::smallint);
-SELECT gist_stratnum_btree(18::smallint);
+SELECT gist_stratnum_btree(7);
+SELECT gist_stratnum_btree(3);

doc/src/sgml/gist.sgml

@@ -290,8 +290,8 @@ CREATE INDEX ON my_table USING GIST (my_inet_column inet_ops);
    The optional eleventh method <function>sortsupport</function> is used to
    speed up building a <acronym>GiST</acronym> index.
    The optional twelfth method <function>stratnum</function> is used to
-   translate well-known <literal>RT*StrategyNumber</literal>s (from
-   <filename>src/include/access/stratnum.h</filename>) into strategy numbers
+   translate compare types (from
+   <filename>src/include/nodes/primnodes.h</filename>) into strategy numbers
    used by the operator class.  This lets the core code look up operators for
    temporal constraint indexes.
  </para>
@@ -1173,8 +1173,8 @@ my_sortsupport(PG_FUNCTION_ARGS)
      <term><function>stratnum</function></term>
      <listitem>
       <para>
-       Given an <literal>RT*StrategyNumber</literal> value from
-       <filename>src/include/access/stratnum.h</filename>, returns a strategy
+       Given a <literal>CompareType</literal> value from
+       <filename>src/include/nodes/primnodes.h</filename>, returns a strategy
        number used by this operator class for matching functionality.  The
        function should return <literal>InvalidStrategy</literal> if the
        operator class has no matching strategy.
@@ -1184,7 +1184,7 @@ my_sortsupport(PG_FUNCTION_ARGS)
        This is used for temporal index constraints (i.e., <literal>PRIMARY
        KEY</literal> and <literal>UNIQUE</literal>).  If the operator class
        provides this function and it returns results for
-       <literal>RTEqualStrategyNumber</literal>, it can be used in the
+       <literal>COMPARE_EQ</literal>, it can be used in the
        non-<literal>WITHOUT OVERLAPS</literal> part(s) of an index constraint.
       </para>
 
@@ -1194,7 +1194,7 @@ my_sortsupport(PG_FUNCTION_ARGS)
 
 <programlisting>
 CREATE OR REPLACE FUNCTION my_stratnum(integer)
-RETURNS integer
+RETURNS smallint
 AS 'MODULE_PATHNAME'
 LANGUAGE C STRICT;
 </programlisting>
@@ -1209,12 +1209,12 @@ PG_FUNCTION_INFO_V1(my_stratnum);
 Datum
 my_stratnum(PG_FUNCTION_ARGS)
 {
-    StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(1);
+    CompareType cmptype = PG_GETARG_INT32(0);
     StrategyNumber ret = InvalidStrategy;
 
-    switch (strategy)
+    switch (cmptype)
     {
-        case RTEqualStrategyNumber:
+        case COMPARE_EQ:
             ret = BTEqualStrategyNumber;
     }
 
@@ -1226,9 +1226,9 @@ my_stratnum(PG_FUNCTION_ARGS)
       <para>
        One translation function is provided by
        <productname>PostgreSQL</productname>:
-       <literal>gist_stratnum_identity</literal> is for operator classes that
-       already use the <literal>RT*StrategyNumber</literal> constants.  It
-       returns whatever is passed to it.  The <literal>btree_gist</literal>
+       <literal>gist_stratnum_common</literal> is for operator classes that
+       use the <literal>RT*StrategyNumber</literal> constants.
+       The <literal>btree_gist</literal>
        extension defines a second translation function,
        <literal>gist_stratnum_btree</literal>, for operator classes that use
        the <literal>BT*StrategyNumber</literal> constants.

doc/src/sgml/xindex.sgml

@@ -592,7 +592,7 @@
       </row>
       <row>
        <entry><function>stratnum</function></entry>
-       <entry>translate well-known strategy numbers to ones
+       <entry>translate compare types to strategy numbers
         used by the operator class (optional)</entry>
        <entry>12</entry>
       </row>

src/backend/access/gist/gistutil.c

@@ -1058,27 +1058,44 @@ gistGetFakeLSN(Relation rel)
 }
 
 /*
- * Returns the same number that was received.
- *
- * This is for GiST opclasses that use the RT*StrategyNumber constants.
+ * This is a stratnum support function for GiST opclasses that use the
+ * RT*StrategyNumber constants.
  */
 Datum
-gist_stratnum_identity(PG_FUNCTION_ARGS)
+gist_stratnum_common(PG_FUNCTION_ARGS)
 {
-	StrategyNumber strat = PG_GETARG_UINT16(0);
+	CompareType cmptype = PG_GETARG_INT32(0);
 
-	PG_RETURN_UINT16(strat);
+	switch (cmptype)
+	{
+		case COMPARE_EQ:
+			PG_RETURN_UINT16(RTEqualStrategyNumber);
+		case COMPARE_LT:
+			PG_RETURN_UINT16(RTLessStrategyNumber);
+		case COMPARE_LE:
+			PG_RETURN_UINT16(RTLessEqualStrategyNumber);
+		case COMPARE_GT:
+			PG_RETURN_UINT16(RTGreaterStrategyNumber);
+		case COMPARE_GE:
+			PG_RETURN_UINT16(RTGreaterEqualStrategyNumber);
+		case COMPARE_OVERLAP:
+			PG_RETURN_UINT16(RTOverlapStrategyNumber);
+		case COMPARE_CONTAINED_BY:
+			PG_RETURN_UINT16(RTContainedByStrategyNumber);
+		default:
+			PG_RETURN_UINT16(InvalidStrategy);
+	}
 }
 
 /*
- * Returns the opclass's private stratnum used for the given strategy.
+ * Returns the opclass's private stratnum used for the given compare type.
  *
  * Calls the opclass's GIST_STRATNUM_PROC support function, if any,
  * and returns the result.
  * Returns InvalidStrategy if the function is not defined.
  */
 StrategyNumber
-GistTranslateStratnum(Oid opclass, StrategyNumber strat)
+GistTranslateStratnum(Oid opclass, CompareType cmptype)
 {
 	Oid			opfamily;
 	Oid			opcintype;
@@ -1095,6 +1112,6 @@ GistTranslateStratnum(Oid opclass, StrategyNumber strat)
 		return InvalidStrategy;
 
 	/* Ask the translation function */
-	result = OidFunctionCall1Coll(funcid, InvalidOid, UInt16GetDatum(strat));
+	result = OidFunctionCall1Coll(funcid, InvalidOid, Int32GetDatum(cmptype));
 	return DatumGetUInt16(result);
 }

src/backend/access/gist/gistvalidate.c

@@ -148,7 +148,7 @@ gistvalidate(Oid opclassoid)
 				break;
 			case GIST_STRATNUM_PROC:
 				ok = check_amproc_signature(procform->amproc, INT2OID, true,
-											1, 1, INT2OID);
+											1, 1, INT4OID);
 				break;
 			default:
 				ereport(INFO,

src/backend/catalog/pg_constraint.c

@@ -1647,22 +1647,22 @@ FindFKPeriodOpers(Oid opclass,
 	 * of the old value, then we can treat the attribute as if it didn't
 	 * change, and skip the RI check.
 	 */
-	strat = RTContainedByStrategyNumber;
-	GetOperatorFromWellKnownStrategy(opclass,
-									 InvalidOid,
-									 containedbyoperoid,
-									 &strat);
+	GetOperatorFromCompareType(opclass,
+							   InvalidOid,
+							   COMPARE_CONTAINED_BY,
+							   containedbyoperoid,
+							   &strat);
 
 	/*
 	 * Now look up the ContainedBy operator. Its left arg must be the type of
 	 * the column (or rather of the opclass). Its right arg must match the
 	 * return type of the support proc.
 	 */
-	strat = RTContainedByStrategyNumber;
-	GetOperatorFromWellKnownStrategy(opclass,
-									 ANYMULTIRANGEOID,
-									 aggedcontainedbyoperoid,
-									 &strat);
+	GetOperatorFromCompareType(opclass,
+							   ANYMULTIRANGEOID,
+							   COMPARE_CONTAINED_BY,
+							   aggedcontainedbyoperoid,
+							   &strat);
 }
 
 /*

src/backend/commands/indexcmds.c

@@ -2178,15 +2178,15 @@ ComputeIndexAttrs(IndexInfo *indexInfo,
 		}
 		else if (iswithoutoverlaps)
 		{
+			CompareType cmptype;
 			StrategyNumber strat;
 			Oid			opid;
 
 			if (attn == nkeycols - 1)
-				strat = RTOverlapStrategyNumber;
+				cmptype = COMPARE_OVERLAP;
 			else
-				strat = RTEqualStrategyNumber;
-			GetOperatorFromWellKnownStrategy(opclassOids[attn], InvalidOid,
-											 &opid, &strat);
+				cmptype = COMPARE_EQ;
+			GetOperatorFromCompareType(opclassOids[attn], InvalidOid, cmptype, &opid, &strat);
 			indexInfo->ii_ExclusionOps[attn] = opid;
 			indexInfo->ii_ExclusionProcs[attn] = get_opcode(opid);
 			indexInfo->ii_ExclusionStrats[attn] = strat;
@@ -2422,30 +2422,28 @@ GetDefaultOpClass(Oid type_id, Oid am_id)
 }
 
 /*
- * GetOperatorFromWellKnownStrategy
+ * GetOperatorFromCompareType
  *
  * opclass - the opclass to use
  * rhstype - the type for the right-hand side, or InvalidOid to use the type of the given opclass.
+ * cmptype - kind of operator to find
  * opid - holds the operator we found
- * strat - holds the input and output strategy number
+ * strat - holds the output strategy number
  *
- * Finds an operator from a "well-known" strategy number.  This is used for
- * temporal index constraints (and other temporal features) to look up
- * equality and overlaps operators, since the strategy numbers for non-btree
- * indexams need not follow any fixed scheme.  We ask an opclass support
- * function to translate from the well-known number to the internal value.  If
- * the function isn't defined or it gives no result, we return
- * InvalidStrategy.
+ * Finds an operator from a CompareType.  This is used for temporal index
+ * constraints (and other temporal features) to look up equality and overlaps
+ * operators.  We ask an opclass support function to translate from the
+ * compare type to the internal strategy numbers.  If the function isn't
+ * defined or it gives no result, we set *strat to InvalidStrategy.
  */
 void
-GetOperatorFromWellKnownStrategy(Oid opclass, Oid rhstype,
-								 Oid *opid, StrategyNumber *strat)
+GetOperatorFromCompareType(Oid opclass, Oid rhstype, CompareType cmptype,
+						   Oid *opid, StrategyNumber *strat)
 {
 	Oid			opfamily;
 	Oid			opcintype;
-	StrategyNumber instrat = *strat;
 
-	Assert(instrat == RTEqualStrategyNumber || instrat == RTOverlapStrategyNumber || instrat == RTContainedByStrategyNumber);
+	Assert(cmptype == COMPARE_EQ || cmptype == COMPARE_OVERLAP || cmptype == COMPARE_CONTAINED_BY);
 
 	*opid = InvalidOid;
 
@@ -2457,7 +2455,7 @@ GetOperatorFromWellKnownStrategy(Oid opclass, Oid rhstype,
 		 * For now we only need GiST support, but this could support other
 		 * indexams if we wanted.
 		 */
-		*strat = GistTranslateStratnum(opclass, instrat);
+		*strat = GistTranslateStratnum(opclass, cmptype);
 		if (*strat == InvalidStrategy)
 		{
 			HeapTuple	tuple;
@@ -2468,11 +2466,11 @@ GetOperatorFromWellKnownStrategy(Oid opclass, Oid rhstype,
 
 			ereport(ERROR,
 					errcode(ERRCODE_UNDEFINED_OBJECT),
-					instrat == RTEqualStrategyNumber ? errmsg("could not identify an equality operator for type %s", format_type_be(opcintype)) :
-					instrat == RTOverlapStrategyNumber ? errmsg("could not identify an overlaps operator for type %s", format_type_be(opcintype)) :
-					instrat == RTContainedByStrategyNumber ? errmsg("could not identify a contained-by operator for type %s", format_type_be(opcintype)) : 0,
-					errdetail("Could not translate strategy number %d for operator class \"%s\" for access method \"%s\".",
-							  instrat, NameStr(((Form_pg_opclass) GETSTRUCT(tuple))->opcname), "gist"));
+					cmptype = COMPARE_EQ ? errmsg("could not identify an equality operator for type %s", format_type_be(opcintype)) :
+					cmptype == COMPARE_OVERLAP ? errmsg("could not identify an overlaps operator for type %s", format_type_be(opcintype)) :
+					cmptype == COMPARE_CONTAINED_BY ? errmsg("could not identify a contained-by operator for type %s", format_type_be(opcintype)) : 0,
+					errdetail("Could not translate compare type %d for operator class \"%s\" for access method \"%s\".",
+							  cmptype, NameStr(((Form_pg_opclass) GETSTRUCT(tuple))->opcname), "gist"));
 		}
 
 		/*
@@ -2495,9 +2493,9 @@ GetOperatorFromWellKnownStrategy(Oid opclass, Oid rhstype,
 
 		ereport(ERROR,
 				errcode(ERRCODE_UNDEFINED_OBJECT),
-				instrat == RTEqualStrategyNumber ? errmsg("could not identify an equality operator for type %s", format_type_be(opcintype)) :
-				instrat == RTOverlapStrategyNumber ? errmsg("could not identify an overlaps operator for type %s", format_type_be(opcintype)) :
-				instrat == RTContainedByStrategyNumber ? errmsg("could not identify a contained-by operator for type %s", format_type_be(opcintype)) : 0,
+				cmptype == COMPARE_EQ ? errmsg("could not identify an equality operator for type %s", format_type_be(opcintype)) :
+				cmptype == COMPARE_OVERLAP ? errmsg("could not identify an overlaps operator for type %s", format_type_be(opcintype)) :
+				cmptype == COMPARE_CONTAINED_BY ? errmsg("could not identify a contained-by operator for type %s", format_type_be(opcintype)) : 0,
 				errdetail("There is no suitable operator in operator family \"%s\" for access method \"%s\".",
 						  NameStr(((Form_pg_opfamily) GETSTRUCT(tuple))->opfname), "gist"));
 	}

src/backend/commands/tablecmds.c

@@ -9997,7 +9997,7 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 
 		if (with_period)
 		{
-			StrategyNumber rtstrategy;
+			CompareType cmptype;
 			bool		for_overlaps = with_period && i == numpks - 1;
 
 			/*
@@ -10007,14 +10007,14 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			if (amid != GIST_AM_OID)
 				elog(ERROR, "only GiST indexes are supported for temporal foreign keys");
 
-			rtstrategy = for_overlaps ? RTOverlapStrategyNumber : RTEqualStrategyNumber;
+			cmptype = for_overlaps ? COMPARE_OVERLAP : COMPARE_EQ;
 
 			/*
 			 * An opclass can use whatever strategy numbers it wants, so we
 			 * ask the opclass what number it actually uses instead of our RT*
 			 * constants.
 			 */
-			eqstrategy = GistTranslateStratnum(opclasses[i], rtstrategy);
+			eqstrategy = GistTranslateStratnum(opclasses[i], cmptype);
 			if (eqstrategy == InvalidStrategy)
 			{
 				HeapTuple	tuple;
@@ -10028,8 +10028,8 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						for_overlaps
 						? errmsg("could not identify an overlaps operator for foreign key")
 						: errmsg("could not identify an equality operator for foreign key"),
-						errdetail("Could not translate strategy number %d for operator class \"%s\" for access method \"%s\".",
-								  rtstrategy, NameStr(((Form_pg_opclass) GETSTRUCT(tuple))->opcname), "gist"));
+						errdetail("Could not translate compare type %d for operator class \"%s\" for access method \"%s\".",
+								  cmptype, NameStr(((Form_pg_opclass) GETSTRUCT(tuple))->opcname), "gist"));
 			}
 		}
 		else

src/backend/executor/execReplication.c

@@ -57,7 +57,7 @@ get_equal_strategy_number(Oid opclass)
 			ret = HTEqualStrategyNumber;
 			break;
 		case GIST_AM_OID:
-			ret = GistTranslateStratnum(opclass, RTEqualStrategyNumber);
+			ret = GistTranslateStratnum(opclass, COMPARE_EQ);
 			break;
 		default:
 			ret = InvalidStrategy;

src/include/access/gist.h

@@ -247,6 +247,7 @@ typedef struct
 	do { (e).key = (k); (e).rel = (r); (e).page = (pg); \
 		 (e).offset = (o); (e).leafkey = (l); } while (0)
 
-extern StrategyNumber GistTranslateStratnum(Oid opclass, StrategyNumber strat);
+enum CompareType;
+extern StrategyNumber GistTranslateStratnum(Oid opclass, enum CompareType cmp);
 
 #endif							/* GIST_H */

src/include/catalog/pg_amproc.dat

@@ -508,7 +508,7 @@
   amprocrighttype => 'box', amprocnum => '8', amproc => 'gist_box_distance' },
 { amprocfamily => 'gist/box_ops', amproclefttype => 'box',
   amprocrighttype => 'box', amprocnum => '12',
-  amproc => 'gist_stratnum_identity' },
+  amproc => 'gist_stratnum_common' },
 { amprocfamily => 'gist/poly_ops', amproclefttype => 'polygon',
   amprocrighttype => 'polygon', amprocnum => '1',
   amproc => 'gist_poly_consistent' },
@@ -530,7 +530,7 @@
   amproc => 'gist_poly_distance' },
 { amprocfamily => 'gist/poly_ops', amproclefttype => 'polygon',
   amprocrighttype => 'polygon', amprocnum => '12',
-  amproc => 'gist_stratnum_identity' },
+  amproc => 'gist_stratnum_common' },
 { amprocfamily => 'gist/circle_ops', amproclefttype => 'circle',
   amprocrighttype => 'circle', amprocnum => '1',
   amproc => 'gist_circle_consistent' },
@@ -551,7 +551,7 @@
   amproc => 'gist_circle_distance' },
 { amprocfamily => 'gist/circle_ops', amproclefttype => 'circle',
   amprocrighttype => 'circle', amprocnum => '12',
-  amproc => 'gist_stratnum_identity' },
+  amproc => 'gist_stratnum_common' },
 { amprocfamily => 'gist/tsvector_ops', amproclefttype => 'tsvector',
   amprocrighttype => 'tsvector', amprocnum => '1',
   amproc => 'gtsvector_consistent(internal,tsvector,int2,oid,internal)' },
@@ -608,7 +608,7 @@
   amproc => 'range_gist_same' },
 { amprocfamily => 'gist/range_ops', amproclefttype => 'anyrange',
   amprocrighttype => 'anyrange', amprocnum => '12',
-  amproc => 'gist_stratnum_identity' },
+  amproc => 'gist_stratnum_common' },
 { amprocfamily => 'gist/network_ops', amproclefttype => 'inet',
   amprocrighttype => 'inet', amprocnum => '1',
   amproc => 'inet_gist_consistent' },
@@ -627,7 +627,7 @@
   amprocrighttype => 'inet', amprocnum => '9', amproc => 'inet_gist_fetch' },
 { amprocfamily => 'gist/network_ops', amproclefttype => 'inet',
   amprocrighttype => 'inet', amprocnum => '12',
-  amproc => 'gist_stratnum_identity' },
+  amproc => 'gist_stratnum_common' },
 { amprocfamily => 'gist/multirange_ops', amproclefttype => 'anymultirange',
   amprocrighttype => 'anymultirange', amprocnum => '1',
   amproc => 'multirange_gist_consistent' },
@@ -648,7 +648,7 @@
   amproc => 'range_gist_same' },
 { amprocfamily => 'gist/multirange_ops', amproclefttype => 'anymultirange',
   amprocrighttype => 'anymultirange', amprocnum => '12',
-  amproc => 'gist_stratnum_identity' },
+  amproc => 'gist_stratnum_common' },
 
 # gin
 { amprocfamily => 'gin/array_ops', amproclefttype => 'anyarray',

src/include/catalog/pg_proc.dat

@@ -12425,8 +12425,8 @@
 
 # GiST stratnum implementations
 { oid => '8047', descr => 'GiST support',
-  proname => 'gist_stratnum_identity', prorettype => 'int2',
-  proargtypes => 'int2',
-  prosrc => 'gist_stratnum_identity' },
+  proname => 'gist_stratnum_common', prorettype => 'int2',
+  proargtypes => 'int4',
+  prosrc => 'gist_stratnum_common' },
 
 ]

src/include/commands/defrem.h

@@ -50,8 +50,8 @@ extern bool CheckIndexCompatible(Oid oldId,
 extern Oid	GetDefaultOpClass(Oid type_id, Oid am_id);
 extern Oid	ResolveOpClass(const List *opclass, Oid attrType,
 						   const char *accessMethodName, Oid accessMethodId);
-extern void GetOperatorFromWellKnownStrategy(Oid opclass, Oid rhstype,
-											 Oid *opid, StrategyNumber *strat);
+extern void GetOperatorFromCompareType(Oid opclass, Oid rhstype, CompareType cmptype,
+									   Oid *opid, StrategyNumber *strat);
 
 /* commands/functioncmds.c */
 extern ObjectAddress CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt);

src/include/nodes/primnodes.h

@@ -1446,7 +1446,7 @@ typedef struct RowExpr
  * (some of) the operators without needing hardcoded knowledge of index AM's
  * strategy numbering.
  *
- * XXX Currently, this mapping is not fully developed and the values are
+ * XXX Currently, this mapping is not fully developed and most values are
  * chosen to match btree strategy numbers, which is not going to work very
  * well for other access methods.
  */
@@ -1458,6 +1458,8 @@ typedef enum CompareType
 	COMPARE_GE = 4,				/* BTGreaterEqualStrategyNumber */
 	COMPARE_GT = 5,				/* BTGreaterStrategyNumber */
 	COMPARE_NE = 6,				/* no such btree strategy */
+	COMPARE_OVERLAP,
+	COMPARE_CONTAINED_BY,
 } CompareType;
 
 /*

src/test/regress/expected/misc_functions.out

@@ -891,15 +891,15 @@ SELECT pg_column_toast_chunk_id(a) IS NULL,
 DROP TABLE test_chunk_id;
 DROP FUNCTION explain_mask_costs(text, bool, bool, bool, bool);
 -- test stratnum support functions
-SELECT gist_stratnum_identity(3::smallint);
- gist_stratnum_identity 
-------------------------
-                      3
+SELECT gist_stratnum_common(7);
+ gist_stratnum_common 
+----------------------
+                    3
 (1 row)
 
-SELECT gist_stratnum_identity(18::smallint);
- gist_stratnum_identity 
-------------------------
-                     18
+SELECT gist_stratnum_common(3);
+ gist_stratnum_common 
+----------------------
+                   18
 (1 row)
 

src/test/regress/sql/misc_functions.sql

@@ -401,5 +401,5 @@ DROP TABLE test_chunk_id;
 DROP FUNCTION explain_mask_costs(text, bool, bool, bool, bool);
 
 -- test stratnum support functions
-SELECT gist_stratnum_identity(3::smallint);
-SELECT gist_stratnum_identity(18::smallint);
+SELECT gist_stratnum_common(7);
+SELECT gist_stratnum_common(3);