From eb7fe3763b31d30d48ebbd4934085fe70315249a Mon Sep 17 00:00:00 2001
From: David Geier <geidav.pg@gmail.com>
Date: Mon, 10 Nov 2025 13:35:01 +0100
Subject: [PATCH v1 2/8] Optimized comparison functions

---
 src/backend/access/gin/ginutil.c | 19 ++++++++++++-------
 src/include/access/gin_private.h | 19 +++++++++++++++----
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index d205093e21d..f4139effd6e 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -114,6 +114,7 @@ initGinState(GinState *state, Relation index)
 	for (i = 0; i < origTupdesc->natts; i++)
 	{
 		Form_pg_attribute attr = TupleDescAttr(origTupdesc, i);
+		FunctionCallInfoBaseData *fci  = &state->compareFnCallInfo[i].fcinfo;
 
 		if (state->oneCol)
 			state->tupdesc[i] = state->origTupdesc;
@@ -222,6 +223,10 @@ initGinState(GinState *state, Relation index)
 			state->supportCollation[i] = index->rd_indcollation[i];
 		else
 			state->supportCollation[i] = DEFAULT_COLLATION_OID;
+
+		InitFunctionCallInfoData(*fci, &state->compareFn[i], 2, state->supportCollation[i], NULL, NULL);
+		fci->args[0].isnull = false;
+		fci->args[1].isnull = false;
 	}
 }
 
@@ -402,8 +407,7 @@ typedef struct
 
 typedef struct
 {
-	FmgrInfo   *cmpDatumFunc;
-	Oid			collation;
+	FunctionCallInfoBaseData   *cmpFuncInfo;
 	bool		haveDups;
 } cmpEntriesArg;
 
@@ -425,9 +429,11 @@ cmpEntries(const void *a, const void *b, void *arg)
 	else if (bb->isnull)
 		res = -1;				/* not-NULL "<" NULL */
 	else
-		res = DatumGetInt32(FunctionCall2Coll(data->cmpDatumFunc,
-											  data->collation,
-											  aa->datum, bb->datum));
+	{
+		data->cmpFuncInfo->args[0].value = aa->datum;
+		data->cmpFuncInfo->args[1].value = bb->datum;
+		res = DatumGetInt32(FunctionCallInvoke(data->cmpFuncInfo));
+	}
 
 	/*
 	 * Detect if we have any duplicates.  If there are equal keys, qsort must
@@ -518,8 +524,7 @@ ginExtractEntries(GinState *ginstate, OffsetNumber attnum,
 			keydata[i].isnull = nullFlags[i];
 		}
 
-		arg.cmpDatumFunc = &ginstate->compareFn[attnum - 1];
-		arg.collation = ginstate->supportCollation[attnum - 1];
+		arg.cmpFuncInfo = &ginstate->compareFnCallInfo[attnum - 1].fcinfo;
 		arg.haveDups = false;
 		qsort_arg(keydata, *nentries, sizeof(keyEntryData),
 				  cmpEntries, &arg);
diff --git a/src/include/access/gin_private.h b/src/include/access/gin_private.h
index e155045ce8a..7cf19c8a5dc 100644
--- a/src/include/access/gin_private.h
+++ b/src/include/access/gin_private.h
@@ -51,6 +51,11 @@ typedef struct GinOptions
 #define GIN_SHARE	BUFFER_LOCK_SHARE
 #define GIN_EXCLUSIVE  BUFFER_LOCK_EXCLUSIVE
 
+typedef union CompareFuncCallInfoData
+{
+	FunctionCallInfoBaseData fcinfo;
+	char fcinfo_data[SizeForFunctionCallInfo(2)];
+} CompareFuncCallInfoData;
 
 /*
  * GinState: working data structure describing the index being worked on
@@ -77,6 +82,10 @@ typedef struct GinState
 	/*
 	 * Per-index-column opclass support functions
 	 */
+
+
+	CompareFuncCallInfoData compareFnCallInfo[INDEX_MAX_KEYS];
+
 	FmgrInfo	compareFn[INDEX_MAX_KEYS];
 	FmgrInfo	extractValueFn[INDEX_MAX_KEYS];
 	FmgrInfo	extractQueryFn[INDEX_MAX_KEYS];
@@ -504,6 +513,8 @@ ginCompareEntries(GinState *ginstate, OffsetNumber attnum,
 				  Datum a, GinNullCategory categorya,
 				  Datum b, GinNullCategory categoryb)
 {
+	FunctionCallInfoBaseData *fci;
+
 	/* if not of same null category, sort by that first */
 	if (categorya != categoryb)
 		return (categorya < categoryb) ? -1 : 1;
@@ -512,10 +523,10 @@ ginCompareEntries(GinState *ginstate, OffsetNumber attnum,
 	if (categorya != GIN_CAT_NORM_KEY)
 		return 0;
 
-	/* both not null, so safe to call the compareFn */
-	return DatumGetInt32(FunctionCall2Coll(&ginstate->compareFn[attnum - 1],
-										   ginstate->supportCollation[attnum - 1],
-										   a, b));
+	fci = &ginstate->compareFnCallInfo[attnum - 1].fcinfo;
+	fci->args[0].value = a;
+	fci->args[1].value = b;
+	return DatumGetInt32(FunctionCallInvoke(fci));
 }
 
 /*
-- 
2.51.0