v18-0001-Refactor-heap_page_prune_and_freeze-parameters-i.patch

From d385615495305be4d42aeee0422dfeef8d26f3a9 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Tue, 14 Oct 2025 11:10:25 -0400
Subject: [PATCH v18 01/12] Refactor heap_page_prune_and_freeze() parameters
 into a struct
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heap_page_prune_and_freeze() had accumulated an unwieldy number of input
parameters, and upcoming work to handle VM updates in this function will
add even more.

Introduce a new PruneFreezeParams struct to group the function’s input
parameters, improving readability and maintainability.

Discussion: https://postgr.es/m/yn4zp35kkdsjx6wf47zcfmxgexxt4h2og47pvnw2x5ifyrs3qc%407uw6jyyxuyf7
---
 src/backend/access/heap/pruneheap.c  | 86 +++++++++++++---------------
 src/backend/access/heap/vacuumlazy.c | 16 ++++--
 src/include/access/heapam.h          | 62 ++++++++++++++++----
 src/tools/pgindent/typedefs.list     |  1 +
 4 files changed, 101 insertions(+), 64 deletions(-)

diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c
index 231bea679c6..450b2eb6494 100644
--- a/src/backend/access/heap/pruneheap.c
+++ b/src/backend/access/heap/pruneheap.c
@@ -258,15 +258,23 @@ heap_page_prune_opt(Relation relation, Buffer buffer)
 		if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
 		{
 			OffsetNumber dummy_off_loc;
+			PruneFreezeParams params;
 			PruneFreezeResult presult;
 
+			params.relation = relation;
+			params.buffer = buffer;
+			params.reason = PRUNE_ON_ACCESS;
+			params.vistest = vistest;
+			params.cutoffs = NULL;
+
 			/*
 			 * For now, pass mark_unused_now as false regardless of whether or
 			 * 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);
+			params.options = 0;
+
+			heap_page_prune_and_freeze(&params, &presult, &dummy_off_loc, NULL, NULL);
 
 			/*
 			 * Report the number of tuples reclaimed to pgstats.  This is
@@ -419,60 +427,43 @@ heap_page_will_freeze(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
- * 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
- * are required when freezing.  When HEAP_PRUNE_FREEZE option is set, we also
- * set presult->all_visible and presult->all_frozen on exit, to indicate if
- * the VM bits can be set.  They are always set to false when the
- * 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).
+ * params contains the input parameters used to control freezing and pruning
+ * behavior. See the definition of PruneFreezeParams for more on what each
+ * parameter does.
  *
- * 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.
+ * If the HEAP_PRUNE_FREEZE option is set in params, 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
+ * 'params.cutoffs', 'presult', 'new_relfrozen_xid' and 'new_relmin_mxid'
+ * arguments are required when freezing.  When HEAP_PRUNE_FREEZE option is
+ * passed, we also set presult->all_visible and presult->all_frozen on exit,
+ * to indicate if the VM bits can be set.  They are always set to false when
+ * the HEAP_PRUNE_FREEZE option is not passed, because at the moment only
+ * callers that also freeze need that information.
  *
  * 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.
  *
  * new_relfrozen_xid and new_relmin_mxid must provided by the caller if the
- * HEAP_PRUNE_FREEZE option is set.  On entry, they contain the oldest XID and
- * multi-XID seen on the relation so far.  They will be updated with oldest
- * values present on the page after pruning.  After processing the whole
- * relation, VACUUM can use these values as the new relfrozenxid/relminmxid
- * for the relation.
+ * HEAP_PRUNE_FREEZE option is set in params.  On entry, they contain the
+ * oldest XID and multi-XID seen on the relation so far.  They will be updated
+ * with oldest values present on the page after pruning.  After processing the
+ * whole relation, VACUUM can use these values as the new
+ * relfrozenxid/relminmxid for the relation.
  */
 void
-heap_page_prune_and_freeze(Relation relation, Buffer buffer,
-						   GlobalVisState *vistest,
-						   int options,
-						   struct VacuumCutoffs *cutoffs,
+heap_page_prune_and_freeze(PruneFreezeParams *params,
 						   PruneFreezeResult *presult,
-						   PruneReason reason,
 						   OffsetNumber *off_loc,
 						   TransactionId *new_relfrozen_xid,
 						   MultiXactId *new_relmin_mxid)
 {
+	Buffer		buffer = params->buffer;
 	Page		page = BufferGetPage(buffer);
 	BlockNumber blockno = BufferGetBlockNumber(buffer);
 	OffsetNumber offnum,
@@ -486,10 +477,11 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
 	int64		fpi_before = pgWalUsage.wal_fpi;
 
 	/* Copy parameters to prstate */
-	prstate.vistest = vistest;
-	prstate.mark_unused_now = (options & HEAP_PAGE_PRUNE_MARK_UNUSED_NOW) != 0;
-	prstate.attempt_freeze = (options & HEAP_PAGE_PRUNE_FREEZE) != 0;
-	prstate.cutoffs = cutoffs;
+	prstate.vistest = params->vistest;
+	prstate.mark_unused_now =
+		(params->options & HEAP_PAGE_PRUNE_MARK_UNUSED_NOW) != 0;
+	prstate.attempt_freeze = (params->options & HEAP_PAGE_PRUNE_FREEZE) != 0;
+	prstate.cutoffs = params->cutoffs;
 
 	/*
 	 * Our strategy is to scan the page and make lists of items to change,
@@ -583,7 +575,7 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
 	prstate.visibility_cutoff_xid = InvalidTransactionId;
 
 	maxoff = PageGetMaxOffsetNumber(page);
-	tup.t_tableOid = RelationGetRelid(relation);
+	tup.t_tableOid = RelationGetRelid(params->relation);
 
 	/*
 	 * Determine HTSV for all tuples, and queue them up for processing as HOT
@@ -786,7 +778,7 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
 	 * Decide if we want to go ahead with freezing according to the freeze
 	 * plans we prepared, or not.
 	 */
-	do_freeze = heap_page_will_freeze(relation, buffer,
+	do_freeze = heap_page_will_freeze(params->relation, buffer,
 									  did_tuple_hint_fpi,
 									  do_prune,
 									  do_hint_prune,
@@ -838,7 +830,7 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
 		/*
 		 * Emit a WAL XLOG_HEAP2_PRUNE* record showing what we did
 		 */
-		if (RelationNeedsWAL(relation))
+		if (RelationNeedsWAL(params->relation))
 		{
 			/*
 			 * The snapshotConflictHorizon for the whole record should be the
@@ -876,11 +868,11 @@ heap_page_prune_and_freeze(Relation relation, Buffer buffer,
 			else
 				conflict_xid = prstate.latest_xid_removed;
 
-			log_heap_prune_and_freeze(relation, buffer,
+			log_heap_prune_and_freeze(params->relation, buffer,
 									  InvalidBuffer,	/* vmbuffer */
 									  0,	/* vmflags */
 									  conflict_xid,
-									  true, reason,
+									  true, params->reason,
 									  prstate.frozen, prstate.nfrozen,
 									  prstate.redirected, prstate.nredirected,
 									  prstate.nowdead, prstate.ndead,
diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 71fbd68c8ea..7db7c56311b 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -1964,10 +1964,16 @@ lazy_scan_prune(LVRelState *vacrel,
 {
 	Relation	rel = vacrel->rel;
 	PruneFreezeResult presult;
-	int			prune_options = 0;
+	PruneFreezeParams params;
 
 	Assert(BufferGetBlockNumber(buf) == blkno);
 
+	params.relation = rel;
+	params.buffer = buf;
+	params.reason = PRUNE_VACUUM_SCAN;
+	params.cutoffs = &vacrel->cutoffs;
+	params.vistest = vacrel->vistest;
+
 	/*
 	 * Prune all HOT-update chains and potentially freeze tuples on this page.
 	 *
@@ -1983,12 +1989,12 @@ lazy_scan_prune(LVRelState *vacrel,
 	 * tuples. Pruning will have determined whether or not the page is
 	 * all-visible.
 	 */
-	prune_options = HEAP_PAGE_PRUNE_FREEZE;
+	params.options = HEAP_PAGE_PRUNE_FREEZE;
 	if (vacrel->nindexes == 0)
-		prune_options |= HEAP_PAGE_PRUNE_MARK_UNUSED_NOW;
+		params.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(&params,
+							   &presult,
 							   &vacrel->offnum,
 							   &vacrel->NewRelfrozenXid, &vacrel->NewRelminMxid);
 
diff --git a/src/include/access/heapam.h b/src/include/access/heapam.h
index 8cbff6ab0eb..74a5c24002b 100644
--- a/src/include/access/heapam.h
+++ b/src/include/access/heapam.h
@@ -221,6 +221,55 @@ typedef struct HeapPageFreeze
 
 } HeapPageFreeze;
 
+
+/* 'reason' codes for heap_page_prune_and_freeze() */
+typedef enum
+{
+	PRUNE_ON_ACCESS,			/* on-access pruning */
+	PRUNE_VACUUM_SCAN,			/* VACUUM 1st heap pass */
+	PRUNE_VACUUM_CLEANUP,		/* VACUUM 2nd heap pass */
+} PruneReason;
+
+/*
+ * Input parameters to heap_page_prune_and_freeze()
+ */
+typedef struct PruneFreezeParams
+{
+	Relation	relation;		/* relation containing buffer to be pruned */
+	Buffer		buffer;			/* buffer to be pruned */
+
+	/*
+	 * The reason pruning was performed.  It is used to set the WAL record
+	 * opcode which is used for debugging and analysis purposes.
+	 */
+	PruneReason reason;
+
+	/*
+	 * Contains flag bits:
+	 *
+	 * 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.
+	 */
+	int			options;
+
+	/*
+	 * vistest is used to distinguish whether tuples are DEAD or RECENTLY_DEAD
+	 * (see heap_prune_satisfies_vacuum).
+	 */
+	GlobalVisState *vistest;
+
+	/*
+	 * 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.
+	 */
+	struct VacuumCutoffs *cutoffs;
+} PruneFreezeParams;
+
 /*
  * Per-page state returned by heap_page_prune_and_freeze()
  */
@@ -264,13 +313,6 @@ typedef struct PruneFreezeResult
 	OffsetNumber deadoffsets[MaxHeapTuplesPerPage];
 } PruneFreezeResult;
 
-/* 'reason' codes for heap_page_prune_and_freeze() */
-typedef enum
-{
-	PRUNE_ON_ACCESS,			/* on-access pruning */
-	PRUNE_VACUUM_SCAN,			/* VACUUM 1st heap pass */
-	PRUNE_VACUUM_CLEANUP,		/* VACUUM 2nd heap pass */
-} PruneReason;
 
 /* ----------------
  *		function prototypes for heap access method
@@ -367,12 +409,8 @@ extern TransactionId heap_index_delete_tuples(Relation rel,
 
 /* in heap/pruneheap.c */
 extern void heap_page_prune_opt(Relation relation, Buffer buffer);
-extern void heap_page_prune_and_freeze(Relation relation, Buffer buffer,
-									   GlobalVisState *vistest,
-									   int options,
-									   struct VacuumCutoffs *cutoffs,
+extern void heap_page_prune_and_freeze(PruneFreezeParams *params,
 									   PruneFreezeResult *presult,
-									   PruneReason reason,
 									   OffsetNumber *off_loc,
 									   TransactionId *new_relfrozen_xid,
 									   MultiXactId *new_relmin_mxid);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 5290b91e83e..b221b3699bf 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2342,6 +2342,7 @@ ProjectionPath
 PromptInterruptContext
 ProtocolVersion
 PrsStorage
+PruneFreezeParams
 PruneFreezeResult
 PruneReason
 PruneState
-- 
2.43.0