v14-0003-Reorder-heap_page_prune_and_freeze-parameters.patch

From da4f0d141c8fa673a4651c42efd8bc48cd88c485 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Mon, 15 Sep 2025 12:06:19 -0400
Subject: [PATCH v14 03/24] Reorder heap_page_prune_and_freeze parameters

Move read-only parameters to the beginning of the function, making it
more clear which paramters are inputs and which are input/outputs or
outputs. Also const-qualify VacuumCutoffs, which is not modified in
heap_page_prune_and_freeze().
---
 src/backend/access/heap/pruneheap.c  | 40 ++++++++++++++--------------
 src/backend/access/heap/vacuumlazy.c |  6 +++--
 src/include/access/heapam.h          |  6 ++---
 3 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index d8ea0c78f77..28bd6a56749 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -43,7 +43,7 @@ typedef struct
 	bool		mark_unused_now;
 	/* whether to attempt freezing tuples */
 	bool		freeze;
-	struct VacuumCutoffs *cutoffs;
+	const struct VacuumCutoffs *cutoffs;
 
 	/*-------------------------------------------------------
 	 * Fields describing what to do to the page
@@ -260,8 +260,8 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
 			 * not the relation has indexes, since we cannot safely determine
 			 * that during on-access pruning with the current implementation.
 			 */
-			heap_page_prune_and_freeze(relation, buffer, vistest, 0,
-									   NULL, &presult, PRUNE_ON_ACCESS, &dummy_off_loc, NULL, NULL);
+			heap_page_prune_and_freeze(relation, buffer, PRUNE_ON_ACCESS, 0, NULL,
+									   vistest, &presult, &dummy_off_loc, NULL, NULL);
 
 			/*
 			 * Report the number of tuples reclaimed to pgstats.  This is
@@ -303,7 +303,17 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
  * also need to account for a reduction in the length of the line pointer
  * array following array truncation by us.
  *
- * If the HEAP_PRUNE_FREEZE option is set, we will also freeze tuples if it's
+ * reason indicates why the pruning is performed.  It is included in the WAL
+ * record for debugging and analysis purposes, but otherwise has no effect.
+ *
+ * options:
+ *   MARK_UNUSED_NOW indicates that dead items can be set LP_UNUSED during
+ *   pruning.
+ *
+ *   FREEZE indicates that we will also freeze tuples, and will return
+ *   'all_visible', 'all_frozen' flags to the caller.
+ *
+ * If the HEAP_PRUNE_FREEZE option is set, we will freeze tuples if it's
  * required in order to advance relfrozenxid / relminmxid, or if it's
  * considered advantageous for overall system performance to do so now.  The
  * 'cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid' arguments
@@ -313,29 +323,19 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
  * HEAP_PRUNE_FREEZE option is not set, because at the moment only callers
  * that also freeze need that information.
  *
- * vistest is used to distinguish whether tuples are DEAD or RECENTLY_DEAD
- * (see heap_prune_satisfies_vacuum).
- *
- * options:
- *   MARK_UNUSED_NOW indicates that dead items can be set LP_UNUSED during
- *   pruning.
- *
- *   FREEZE indicates that we will also freeze tuples, and will return
- *   'all_visible', 'all_frozen' flags to the caller.
- *
  * cutoffs contains the freeze cutoffs, established by VACUUM at the beginning
  * of vacuuming the relation.  Required if HEAP_PRUNE_FREEZE option is set.
  * cutoffs->OldestXmin is also used to determine if dead tuples are
  * HEAPTUPLE_RECENTLY_DEAD or HEAPTUPLE_DEAD.
  *
+ * vistest is used to distinguish whether tuples are DEAD or RECENTLY_DEAD
+ * (see heap_prune_satisfies_vacuum).
+ *
  * presult contains output parameters needed by callers, such as the number of
  * tuples removed and the offsets of dead items on the page after pruning.
  * heap_page_prune_and_freeze() is responsible for initializing it.  Required
  * by all callers.
  *
- * reason indicates why the pruning is performed.  It is included in the WAL
- * record for debugging and analysis purposes, but otherwise has no effect.
- *
  * off_loc is the offset location required by the caller to use in error
  * callback.
  *
@@ -348,11 +348,11 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
  */
 void
 heap_page_prune_and_freeze(Relation relation, Buffer buffer,
-						   GlobalVisState *vistest,
+						   PruneReason reason,
 						   int options,
-						   struct VacuumCutoffs *cutoffs,
+						   const struct VacuumCutoffs *cutoffs,
+						   GlobalVisState *vistest,
 						   PruneFreezeResult *presult,
-						   PruneReason reason,
 						   OffsetNumber *off_loc,
 						   TransactionId *new_relfrozen_xid,
 						   MultiXactId *new_relmin_mxid)
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 981d9380a92..ddc9677694c 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -1974,8 +1974,10 @@ lazy_scan_prune(LVRelState *vacrel,
 	if (vacrel->nindexes == 0)
 		prune_options |= HEAP_PAGE_PRUNE_MARK_UNUSED_NOW;
 
-	heap_page_prune_and_freeze(rel, buf, vacrel->vistest, prune_options,
-							   &vacrel->cutoffs, &presult, PRUNE_VACUUM_SCAN,
+	heap_page_prune_and_freeze(rel, buf, PRUNE_VACUUM_SCAN, prune_options,
+							   &vacrel->cutoffs,
+							   vacrel->vistest,
+							   &presult,
 							   &vacrel->offnum,
 							   &vacrel->NewRelfrozenXid, &vacrel->NewRelminMxid);
 
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index a2bd5a897f8..34206a6a7d5 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -374,11 +374,11 @@ extern TransactionId heap_index_delete_tuples(Relation rel,
 struct GlobalVisState;
 extern void heap_page_prune_opt(Relation relation, Buffer buffer);
 extern void heap_page_prune_and_freeze(Relation relation, Buffer buffer,
-									   struct GlobalVisState *vistest,
+									   PruneReason reason,
 									   int options,
-									   struct VacuumCutoffs *cutoffs,
+									   const struct VacuumCutoffs *cutoffs,
+									   struct GlobalVisState *vistest,
 									   PruneFreezeResult *presult,
-									   PruneReason reason,
 									   OffsetNumber *off_loc,
 									   TransactionId *new_relfrozen_xid,
 									   MultiXactId *new_relmin_mxid);
-- 
2.43.0