From eed4a91d7742166124c26dbdadd41aa4695cc5b8 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Sat, 13 Mar 2021 18:48:10 +1300
Subject: [PATCH 5/9] Use qsort_itemptr() and friends in various places.

---
 src/backend/access/heap/vacuumlazy.c | 40 +++-------------------------
 src/backend/executor/nodeTidscan.c   | 32 +++-------------------
 2 files changed, 7 insertions(+), 65 deletions(-)

diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index a65dcbebfa..ef57e88b43 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -79,6 +79,7 @@
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/pg_rusage.h"
+#include "utils/sortitemptr.h"
 #include "utils/timestamp.h"
 
 
@@ -367,7 +368,6 @@ static void lazy_space_alloc(LVRelStats *vacrelstats, BlockNumber relblocks);
 static void lazy_record_dead_tuple(LVDeadTuples *dead_tuples,
 								   ItemPointer itemptr);
 static bool lazy_tid_reaped(ItemPointer itemptr, void *state);
-static int	vac_cmp_itemptr(const void *left, const void *right);
 static bool heap_page_is_all_visible(Relation rel, Buffer buf,
 									 LVRelStats *vacrelstats,
 									 TransactionId *visibility_cutoff_xid, bool *all_frozen);
@@ -2943,45 +2943,13 @@ lazy_tid_reaped(ItemPointer itemptr, void *state)
 	if (item < litem || item > ritem)
 		return false;
 
-	res = (ItemPointer) bsearch((void *) itemptr,
-								(void *) dead_tuples->itemptrs,
-								dead_tuples->num_tuples,
-								sizeof(ItemPointerData),
-								vac_cmp_itemptr);
+	res = bsearch_itemptr(itemptr,
+						  dead_tuples->itemptrs,
+						  dead_tuples->num_tuples);
 
 	return (res != NULL);
 }
 
-/*
- * Comparator routines for use with qsort() and bsearch().
- */
-static int
-vac_cmp_itemptr(const void *left, const void *right)
-{
-	BlockNumber lblk,
-				rblk;
-	OffsetNumber loff,
-				roff;
-
-	lblk = ItemPointerGetBlockNumber((ItemPointer) left);
-	rblk = ItemPointerGetBlockNumber((ItemPointer) right);
-
-	if (lblk < rblk)
-		return -1;
-	if (lblk > rblk)
-		return 1;
-
-	loff = ItemPointerGetOffsetNumber((ItemPointer) left);
-	roff = ItemPointerGetOffsetNumber((ItemPointer) right);
-
-	if (loff < roff)
-		return -1;
-	if (loff > roff)
-		return 1;
-
-	return 0;
-}
-
 /*
  * Check if every tuple in the given page is visible to all current and future
  * transactions. Also return the visibility_cutoff_xid which is the highest
diff --git a/src/backend/executor/nodeTidscan.c b/src/backend/executor/nodeTidscan.c
index 48c3737da2..ee6bc4ee05 100644
--- a/src/backend/executor/nodeTidscan.c
+++ b/src/backend/executor/nodeTidscan.c
@@ -33,6 +33,7 @@
 #include "storage/bufmgr.h"
 #include "utils/array.h"
 #include "utils/rel.h"
+#include "utils/sortitemptr.h"
 
 
 #define IsCTIDVar(node)  \
@@ -51,7 +52,6 @@ typedef struct TidExpr
 
 static void TidExprListCreate(TidScanState *tidstate);
 static void TidListEval(TidScanState *tidstate);
-static int	itemptr_comparator(const void *a, const void *b);
 static TupleTableSlot *TidNext(TidScanState *node);
 
 
@@ -263,10 +263,8 @@ TidListEval(TidScanState *tidstate)
 		/* CurrentOfExpr could never appear OR'd with something else */
 		Assert(!tidstate->tss_isCurrentOf);
 
-		qsort((void *) tidList, numTids, sizeof(ItemPointerData),
-			  itemptr_comparator);
-		numTids = qunique(tidList, numTids, sizeof(ItemPointerData),
-						  itemptr_comparator);
+		qsort_itemptr(tidList, numTids);
+		numTids = unique_itemptr(tidList, numTids);
 	}
 
 	tidstate->tss_TidList = tidList;
@@ -274,30 +272,6 @@ TidListEval(TidScanState *tidstate)
 	tidstate->tss_TidPtr = -1;
 }
 
-/*
- * qsort comparator for ItemPointerData items
- */
-static int
-itemptr_comparator(const void *a, const void *b)
-{
-	const ItemPointerData *ipa = (const ItemPointerData *) a;
-	const ItemPointerData *ipb = (const ItemPointerData *) b;
-	BlockNumber ba = ItemPointerGetBlockNumber(ipa);
-	BlockNumber bb = ItemPointerGetBlockNumber(ipb);
-	OffsetNumber oa = ItemPointerGetOffsetNumber(ipa);
-	OffsetNumber ob = ItemPointerGetOffsetNumber(ipb);
-
-	if (ba < bb)
-		return -1;
-	if (ba > bb)
-		return 1;
-	if (oa < ob)
-		return -1;
-	if (oa > ob)
-		return 1;
-	return 0;
-}
-
 /* ----------------------------------------------------------------
  *		TidNext
  *
-- 
2.30.1