Add stratnum GiST support function

This is support function 12 for the GiST AM and translates
"well-known" RT*StrategyNumber values into whatever strategy number is
used by the opclass (since no particular numbers are actually
required).  We will use this to support temporal PRIMARY
KEY/UNIQUE/FOREIGN KEY/FOR PORTION OF functionality.

This commit adds two implementations, one for internal GiST opclasses
(just an identity function) and another for btree_gist opclasses.  It
updates btree_gist from 1.7 to 1.8, adding the support function for
all its opclasses.

(previously committed as 6db4598fcb, reverted by 8aee330af55; this is
essentially unchanged from those)

Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com

src/backend/access/gist/gistutil.c

@@ -21,6 +21,7 @@
 #include "common/pg_prng.h"
 #include "storage/indexfsm.h"
 #include "utils/float.h"
+#include "utils/fmgrprotos.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
@@ -1055,3 +1056,16 @@ gistGetFakeLSN(Relation rel)
 		return GetFakeLSNForUnloggedRel();
 	}
 }
+
+/*
+ * Returns the same number that was received.
+ *
+ * This is for GiST opclasses that use the RT*StrategyNumber constants.
+ */
+Datum
+gist_stratnum_identity(PG_FUNCTION_ARGS)
+{
+	StrategyNumber strat = PG_GETARG_UINT16(0);
+
+	PG_RETURN_UINT16(strat);
+}

src/backend/access/gist/gistvalidate.c

@@ -146,6 +146,10 @@ gistvalidate(Oid opclassoid)
 				ok = check_amproc_signature(procform->amproc, VOIDOID, true,
 											1, 1, INTERNALOID);
 				break;
+			case GIST_STRATNUM_PROC:
+				ok = check_amproc_signature(procform->amproc, INT2OID, true,
+											1, 1, INT2OID);
+				break;
 			default:
 				ereport(INFO,
 						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
@@ -266,7 +270,8 @@ gistvalidate(Oid opclassoid)
 			continue;			/* got it */
 		if (i == GIST_DISTANCE_PROC || i == GIST_FETCH_PROC ||
 			i == GIST_COMPRESS_PROC || i == GIST_DECOMPRESS_PROC ||
-			i == GIST_OPTIONS_PROC || i == GIST_SORTSUPPORT_PROC)
+			i == GIST_OPTIONS_PROC || i == GIST_SORTSUPPORT_PROC ||
+			i == GIST_STRATNUM_PROC)
 			continue;			/* optional methods */
 		ereport(INFO,
 				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
@@ -338,6 +343,7 @@ gistadjustmembers(Oid opfamilyoid,
 			case GIST_FETCH_PROC:
 			case GIST_OPTIONS_PROC:
 			case GIST_SORTSUPPORT_PROC:
+			case GIST_STRATNUM_PROC:
 				/* Optional, so force it to be a soft family dependency */
 				op->ref_is_hard = false;
 				op->ref_is_family = true;

src/include/access/gist.h

@@ -38,7 +38,8 @@
 #define GIST_FETCH_PROC					9
 #define GIST_OPTIONS_PROC				10
 #define GIST_SORTSUPPORT_PROC			11
-#define GISTNProcs					11
+#define GIST_STRATNUM_PROC				12
+#define GISTNProcs					12
 
 /*
  * Page opaque data in a GiST index page.

src/include/catalog/catversion.h

@@ -57,6 +57,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202409122
+#define CATALOG_VERSION_NO	202409171
 
 #endif

src/include/catalog/pg_amproc.dat

@@ -506,6 +506,9 @@
   amprocrighttype => 'box', amprocnum => '7', amproc => 'gist_box_same' },
 { amprocfamily => 'gist/box_ops', amproclefttype => 'box',
   amprocrighttype => 'box', amprocnum => '8', amproc => 'gist_box_distance' },
+{ amprocfamily => 'gist/box_ops', amproclefttype => 'box',
+  amprocrighttype => 'box', amprocnum => '12',
+  amproc => 'gist_stratnum_identity' },
 { amprocfamily => 'gist/poly_ops', amproclefttype => 'polygon',
   amprocrighttype => 'polygon', amprocnum => '1',
   amproc => 'gist_poly_consistent' },
@@ -525,6 +528,9 @@
 { amprocfamily => 'gist/poly_ops', amproclefttype => 'polygon',
   amprocrighttype => 'polygon', amprocnum => '8',
   amproc => 'gist_poly_distance' },
+{ amprocfamily => 'gist/poly_ops', amproclefttype => 'polygon',
+  amprocrighttype => 'polygon', amprocnum => '12',
+  amproc => 'gist_stratnum_identity' },
 { amprocfamily => 'gist/circle_ops', amproclefttype => 'circle',
   amprocrighttype => 'circle', amprocnum => '1',
   amproc => 'gist_circle_consistent' },
@@ -543,6 +549,9 @@
 { amprocfamily => 'gist/circle_ops', amproclefttype => 'circle',
   amprocrighttype => 'circle', amprocnum => '8',
   amproc => 'gist_circle_distance' },
+{ amprocfamily => 'gist/circle_ops', amproclefttype => 'circle',
+  amprocrighttype => 'circle', amprocnum => '12',
+  amproc => 'gist_stratnum_identity' },
 { amprocfamily => 'gist/tsvector_ops', amproclefttype => 'tsvector',
   amprocrighttype => 'tsvector', amprocnum => '1',
   amproc => 'gtsvector_consistent(internal,tsvector,int2,oid,internal)' },
@@ -597,6 +606,9 @@
 { amprocfamily => 'gist/range_ops', amproclefttype => 'anyrange',
   amprocrighttype => 'anyrange', amprocnum => '7',
   amproc => 'range_gist_same' },
+{ amprocfamily => 'gist/range_ops', amproclefttype => 'anyrange',
+  amprocrighttype => 'anyrange', amprocnum => '12',
+  amproc => 'gist_stratnum_identity' },
 { amprocfamily => 'gist/network_ops', amproclefttype => 'inet',
   amprocrighttype => 'inet', amprocnum => '1',
   amproc => 'inet_gist_consistent' },
@@ -613,6 +625,9 @@
   amprocrighttype => 'inet', amprocnum => '7', amproc => 'inet_gist_same' },
 { amprocfamily => 'gist/network_ops', amproclefttype => 'inet',
   amprocrighttype => 'inet', amprocnum => '9', amproc => 'inet_gist_fetch' },
+{ amprocfamily => 'gist/network_ops', amproclefttype => 'inet',
+  amprocrighttype => 'inet', amprocnum => '12',
+  amproc => 'gist_stratnum_identity' },
 { amprocfamily => 'gist/multirange_ops', amproclefttype => 'anymultirange',
   amprocrighttype => 'anymultirange', amprocnum => '1',
   amproc => 'multirange_gist_consistent' },
@@ -631,6 +646,9 @@
 { amprocfamily => 'gist/multirange_ops', amproclefttype => 'anymultirange',
   amprocrighttype => 'anymultirange', amprocnum => '7',
   amproc => 'range_gist_same' },
+{ amprocfamily => 'gist/multirange_ops', amproclefttype => 'anymultirange',
+  amprocrighttype => 'anymultirange', amprocnum => '12',
+  amproc => 'gist_stratnum_identity' },
 
 # gin
 { amprocfamily => 'gin/array_ops', amproclefttype => 'anyarray',

src/include/catalog/pg_proc.dat

@@ -12310,4 +12310,10 @@
   proargnames => '{summarized_tli,summarized_lsn,pending_lsn,summarizer_pid}',
   prosrc => 'pg_get_wal_summarizer_state' },
 
+# GiST stratnum implementations
+{ oid => '8047', descr => 'GiST support',
+  proname => 'gist_stratnum_identity', prorettype => 'int2',
+  proargtypes => 'int2',
+  prosrc => 'gist_stratnum_identity' },
+
 ]

src/test/regress/expected/misc_functions.out

@@ -819,3 +819,16 @@ 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
+(1 row)
+
+SELECT gist_stratnum_identity(18::smallint);
+ gist_stratnum_identity 
+------------------------
+                     18
+(1 row)
+

src/test/regress/sql/misc_functions.sql

@@ -360,3 +360,7 @@ SELECT pg_column_toast_chunk_id(a) IS NULL,
   FROM test_chunk_id;
 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);