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[PATCH v10 2/2] handle relation statistics correctly during rewrites
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* [PATCH v10 2/2] handle relation statistics correctly during rewrites
@ 2025-11-04 13:52  Bertrand Drouvot <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Bertrand Drouvot @ 2025-11-04 13:52 UTC (permalink / raw)

Now that PGSTAT_KIND_RELATION is keyed by refilenode, we need to handle rewrites.

To do so, this patch:

- Adds PgStat_PendingRewrite, a new struct to track rewrite operations within
a transaction, storing the old locator, new locator, and original locator (for
rewrite chains). This allows stats to be copied from the original location to
the final location at commit time.

- Adds a new function, pgstat_mark_rewrite(), called when a table rewrite begins.
It records the rewrite operation in a local list and detects rewrite chains by
checking if the old_locator matches any existing new_locator, preserving the
chain's original_locator.

- Modifies pgstat_copy_relation_stats(), to accept RelFileLocators instead of
Relations, with a new increment parameter to accumulate stats (needed for rewrite
chains with DML between rewrites).

- Ensures that AtEOXact_PgStat_Relations(), AtPrepare_PgStat_Relations(),
pgstat_twophase_postcommit()/postabort() pgstat_drop_relation() handle the
PgStat_PendingRewrite list correctly.

Note that due to the new flush call in pgstat_twophase_postcommit() we can not
call GetCurrentTransactionStopTimestamp() in pgstat_relation_flush_cb(). So,
adding a check to handle this special case and call GetCurrentTimestamp() instead.
Note that we'd call GetCurrentTimestamp() only if there is a rewrite, so that
the GetCurrentTimestamp() extra cost should be negligible. Another solution
could be to trigger the flush from FinishPreparedTransaction() but that's not
worth the extra complexity.

The new pending_rewrites list is traversed in multiple places. The overhead
should be negligible in comparison to a rewrite and the list should not contain
a lot of rewrites in practice.

The pending_rewrites list is traversed in multiple places. In typical usage,
the list will contain only a few entries so the traversal cost is negligible (
furthermore in comparison to a rewrite).
---
 src/backend/catalog/index.c                  |   2 +-
 src/backend/commands/cluster.c               |   5 +
 src/backend/commands/tablecmds.c             |   6 +
 src/backend/utils/activity/pgstat_relation.c | 391 ++++++++++++++++++-
 src/backend/utils/activity/pgstat_xact.c     |  25 +-
 src/backend/utils/cache/relcache.c           |   6 +
 src/include/pgstat.h                         |   5 +-
 src/tools/pgindent/typedefs.list             |   1 +
 8 files changed, 424 insertions(+), 17 deletions(-)
  92.8% src/backend/utils/activity/
   4.9% src/backend/

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 8dea58ad96b..b71925a22c3 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -1795,7 +1795,7 @@ index_concurrently_swap(Oid newIndexId, Oid oldIndexId, const char *oldName)
 	changeDependenciesOn(RelationRelationId, oldIndexId, newIndexId);
 
 	/* copy over statistics from old to new index */
-	pgstat_copy_relation_stats(newClassRel, oldClassRel);
+	pgstat_copy_relation_stats(newClassRel->rd_locator, oldClassRel->rd_locator, false);
 
 	/* Copy data of pg_statistic from the old index to the new one */
 	CopyStatistics(oldIndexId, newIndexId);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 2120c85ccb4..6155b12afab 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1196,6 +1196,11 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 
 		rel1 = relation_open(r1, NoLock);
 		rel2 = relation_open(r2, NoLock);
+
+		/* Mark that a rewrite happened */
+		if (RELKIND_HAS_STORAGE(rel1->rd_rel->relkind))
+			pgstat_mark_rewrite(rel1->rd_locator, rel2->rd_locator);
+
 		rel2->rd_createSubid = rel1->rd_createSubid;
 		rel2->rd_newRelfilelocatorSubid = rel1->rd_newRelfilelocatorSubid;
 		rel2->rd_firstRelfilelocatorSubid = rel1->rd_firstRelfilelocatorSubid;
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 6b1a00ed477..9de70f321ed 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -16884,6 +16884,7 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 	Oid			reltoastrelid;
 	RelFileNumber newrelfilenumber;
 	RelFileLocator newrlocator;
+	RelFileLocator oldrlocator;
 	List	   *reltoastidxids = NIL;
 	ListCell   *lc;
 
@@ -16922,6 +16923,7 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 	newrlocator = rel->rd_locator;
 	newrlocator.relNumber = newrelfilenumber;
 	newrlocator.spcOid = newTableSpace;
+	oldrlocator = rel->rd_locator;
 
 	/* hand off to AM to actually create new rel storage and copy the data */
 	if (rel->rd_rel->relkind == RELKIND_INDEX)
@@ -16934,6 +16936,10 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 		table_relation_copy_data(rel, &newrlocator);
 	}
 
+	/* mark that a rewrite happened */
+	if (RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
+		pgstat_mark_rewrite(oldrlocator, newrlocator);
+
 	/*
 	 * Update the pg_class row.
 	 *
diff --git a/src/backend/utils/activity/pgstat_relation.c b/src/backend/utils/activity/pgstat_relation.c
index a267e93f8be..123fb50d98f 100644
--- a/src/backend/utils/activity/pgstat_relation.c
+++ b/src/backend/utils/activity/pgstat_relation.c
@@ -30,6 +30,19 @@
 #include "utils/syscache.h"
 #include "utils/timestamp.h"
 
+/* Pending rewrite operations for stats copying */
+typedef struct PgStat_PendingRewrite
+{
+	RelFileLocator old_locator;
+	RelFileLocator new_locator;
+	RelFileLocator original_locator;
+	int			nest_level;		/* Transaction nesting level where rewrite
+								 * occurred */
+	struct PgStat_PendingRewrite *next;
+} PgStat_PendingRewrite;
+
+/* The pending rewrites list for current transaction */
+static PgStat_PendingRewrite *pending_rewrites = NULL;
 
 /* Record that's written to 2PC state file when pgstat state is persisted */
 typedef struct TwoPhasePgStatRecord
@@ -43,6 +56,8 @@ typedef struct TwoPhasePgStatRecord
 	PgStat_Counter deleted_pre_truncdrop;
 	RelFileLocator locator;		/* table's rd_locator */
 	bool		truncdropped;	/* was the relation truncated/dropped? */
+	RelFileLocator rewrite_old_locator;
+	int			rewrite_nest_level;
 } TwoPhasePgStatRecord;
 
 
@@ -54,27 +69,70 @@ static void restore_truncdrop_counters(PgStat_TableXactStatus *trans);
 
 
 /*
- * Copy stats between relations. This is used for things like REINDEX
+ * Copy stats between RelFileLocator. This is used for things like REINDEX
  * CONCURRENTLY.
  */
 void
-pgstat_copy_relation_stats(Relation dst, Relation src)
+pgstat_copy_relation_stats(RelFileLocator dst, RelFileLocator src, bool increment)
 {
 	PgStat_StatTabEntry *srcstats;
 	PgStatShared_Relation *dstshstats;
 	PgStat_EntryRef *dst_ref;
 
-	srcstats = pgstat_fetch_stat_tabentry_ext(RelationGetRelid(src));
+	srcstats = (PgStat_StatTabEntry *) pgstat_fetch_entry(PGSTAT_KIND_RELATION,
+														  src.dbOid,
+														  RelFileLocatorToPgStatObjid(src));
 	if (!srcstats)
 		return;
 
 	dst_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_RELATION,
-										  dst->rd_rel->relisshared ? InvalidOid : MyDatabaseId,
-										  RelationGetRelid(dst),
+										  dst.dbOid,
+										  RelFileLocatorToPgStatObjid(dst),
 										  false);
 
 	dstshstats = (PgStatShared_Relation *) dst_ref->shared_stats;
-	dstshstats->stats = *srcstats;
+
+	if (!increment)
+		dstshstats->stats = *srcstats;
+	else
+	{
+		/* Increment those statistics */
+#define RELFSTAT_ACC(fld, stats_to_add) \
+	(dstshstats->stats.fld += stats_to_add->fld)
+		RELFSTAT_ACC(numscans, srcstats);
+		RELFSTAT_ACC(tuples_returned, srcstats);
+		RELFSTAT_ACC(tuples_fetched, srcstats);
+		RELFSTAT_ACC(tuples_inserted, srcstats);
+		RELFSTAT_ACC(tuples_updated, srcstats);
+		RELFSTAT_ACC(tuples_deleted, srcstats);
+		RELFSTAT_ACC(tuples_hot_updated, srcstats);
+		RELFSTAT_ACC(tuples_newpage_updated, srcstats);
+		RELFSTAT_ACC(live_tuples, srcstats);
+		RELFSTAT_ACC(dead_tuples, srcstats);
+		RELFSTAT_ACC(mod_since_analyze, srcstats);
+		RELFSTAT_ACC(ins_since_vacuum, srcstats);
+		RELFSTAT_ACC(blocks_fetched, srcstats);
+		RELFSTAT_ACC(blocks_hit, srcstats);
+		RELFSTAT_ACC(vacuum_count, srcstats);
+		RELFSTAT_ACC(autovacuum_count, srcstats);
+		RELFSTAT_ACC(analyze_count, srcstats);
+		RELFSTAT_ACC(autoanalyze_count, srcstats);
+		RELFSTAT_ACC(total_vacuum_time, srcstats);
+		RELFSTAT_ACC(total_autovacuum_time, srcstats);
+		RELFSTAT_ACC(total_analyze_time, srcstats);
+		RELFSTAT_ACC(total_autoanalyze_time, srcstats);
+#undef RELFSTAT_ACC
+
+		/* Replace those statistics */
+#define RELFSTAT_REP(fld, stats_to_rep) \
+	(dstshstats->stats.fld = stats_to_rep->fld)
+		RELFSTAT_REP(lastscan, srcstats);
+		RELFSTAT_REP(last_vacuum_time, srcstats);
+		RELFSTAT_REP(last_autovacuum_time, srcstats);
+		RELFSTAT_REP(last_analyze_time, srcstats);
+		RELFSTAT_REP(last_autoanalyze_time, srcstats);
+#undef RELFSTAT_REP
+	}
 
 	pgstat_unlock_entry(dst_ref);
 }
@@ -136,6 +194,7 @@ void
 pgstat_assoc_relation(Relation rel)
 {
 	RelFileLocator locator;
+	PgStat_TableStatus *pgstat_info;
 
 	Assert(rel->pgstat_enabled);
 	Assert(rel->pgstat_info == NULL);
@@ -164,14 +223,54 @@ pgstat_assoc_relation(Relation rel)
 		locator.relNumber = rel->rd_id;
 	}
 
+	/*
+	 * If this relation was rewritten during the current transaction we may be
+	 * reopening it with its new RelFileLocator. In that case, continue using
+	 * the stats entry associated with the old locator rather than creating a
+	 * new one. This ensures all stats from before and after the rewrite are
+	 * tracked in a single entry which will be properly copied to the new
+	 * locator at transaction commit.
+	 */
+	if (pending_rewrites != NULL)
+	{
+		PgStat_PendingRewrite *rewrite;
+
+		for (rewrite = pending_rewrites; rewrite != NULL; rewrite = rewrite->next)
+		{
+			if (locator.dbOid == rewrite->new_locator.dbOid &&
+				locator.spcOid == rewrite->new_locator.spcOid &&
+				locator.relNumber == rewrite->new_locator.relNumber)
+			{
+				pgstat_info = pgstat_prep_relation_pending(rewrite->old_locator);
+				goto found_entry;
+			}
+		}
+	}
+
 	/* Else find or make the PgStat_TableStatus entry, and update link */
-	rel->pgstat_info = pgstat_prep_relation_pending(locator);
+	pgstat_info = pgstat_prep_relation_pending(locator);
+
+found_entry:
+	rel->pgstat_info = pgstat_info;
+
+	/*
+	 * For relations stats, we key by physical file location, not by relation
+	 * OID. This means during operations like ALTER TYPE it's possible that
+	 * the relation OID changes but the relfilenode stays the same (no actual
+	 * rewrite needed). Unlink the old relation first.
+	 */
+	if (pgstat_info->relation != NULL &&
+		pgstat_info->relation != rel)
+	{
+		pgstat_info->relation->pgstat_info = NULL;
+		pgstat_info->relation = NULL;
+	}
 
 	/* don't allow link a stats to multiple relcache entries */
-	Assert(rel->pgstat_info->relation == NULL);
+	Assert(pgstat_info->relation == NULL);
 
 	/* mark this relation as the owner */
-	rel->pgstat_info->relation = rel;
+	pgstat_info->relation = rel;
 }
 
 /*
@@ -214,14 +313,37 @@ pgstat_drop_relation(Relation rel)
 {
 	int			nest_level = GetCurrentTransactionNestLevel();
 	PgStat_TableStatus *pgstat_info;
+	bool		skip_transactional_drop = false;
 
 	/* don't track stats for relations without storage */
 	if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
 		return;
 
-	pgstat_drop_transactional(PGSTAT_KIND_RELATION,
-							  rel->rd_locator.dbOid,
-							  RelFileLocatorToPgStatObjid(rel->rd_locator));
+	/* Check if this drop is part of a pending rewrite */
+	if (pending_rewrites != NULL)
+	{
+		PgStat_PendingRewrite *rewrite;
+
+		for (rewrite = pending_rewrites; rewrite != NULL; rewrite = rewrite->next)
+		{
+			if (rel->rd_locator.dbOid == rewrite->old_locator.dbOid &&
+				rel->rd_locator.spcOid == rewrite->old_locator.spcOid &&
+				rel->rd_locator.relNumber == rewrite->old_locator.relNumber)
+			{
+				skip_transactional_drop = true;
+				break;
+			}
+		}
+	}
+
+	/*
+	 * If it is part of a rewrite, drop its stats later, for example in
+	 * AtEOXact_PgStat_Relations(), so skip it here.
+	 */
+	if (!skip_transactional_drop)
+		pgstat_drop_transactional(PGSTAT_KIND_RELATION,
+								  rel->rd_locator.dbOid,
+								  RelFileLocatorToPgStatObjid(rel->rd_locator));
 
 	if (!pgstat_should_count_relation(rel))
 		return;
@@ -666,6 +788,48 @@ AtEOXact_PgStat_Relations(PgStat_SubXactStatus *xact_state, bool isCommit)
 		}
 		tabstat->trans = NULL;
 	}
+
+	/* preserve the stats in case of rewrite */
+	if (isCommit && pending_rewrites != NULL)
+	{
+		PgStat_PendingRewrite *rewrite;
+		PgStat_PendingRewrite *prev = NULL;
+		PgStat_PendingRewrite *current = pending_rewrites;
+		PgStat_PendingRewrite *next;
+
+		/* reverse the rewrites list to process in chronological order */
+		while (current != NULL)
+		{
+			next = current->next;
+			current->next = prev;
+			prev = current;
+			current = next;
+		}
+
+		/* now process rewrites in chronological order */
+		for (rewrite = prev; rewrite != NULL; rewrite = rewrite->next)
+		{
+			PgStat_EntryRef *old_entry_ref;
+
+			old_entry_ref = pgstat_fetch_pending_entry(PGSTAT_KIND_RELATION,
+													   rewrite->old_locator.dbOid,
+													   RelFileLocatorToPgStatObjid(rewrite->old_locator));
+
+			if (old_entry_ref && old_entry_ref->pending)
+				pgstat_relation_flush_cb(old_entry_ref, false);
+
+			pgstat_copy_relation_stats(rewrite->new_locator,
+									   rewrite->old_locator, true);
+
+			/* drop old locator's stats */
+			if (!pgstat_drop_entry(PGSTAT_KIND_RELATION,
+								   rewrite->old_locator.dbOid,
+								   RelFileLocatorToPgStatObjid(rewrite->old_locator)))
+				pgstat_request_entry_refs_gc();
+		}
+	}
+
+	pending_rewrites = NULL;
 }
 
 /*
@@ -681,6 +845,30 @@ AtEOSubXact_PgStat_Relations(PgStat_SubXactStatus *xact_state, bool isCommit, in
 	PgStat_TableXactStatus *trans;
 	PgStat_TableXactStatus *next_trans;
 
+	/*
+	 * If we don't commit then remove the associated rewrites if any, to keep
+	 * the rewrite chain in sync with what will be eventually committed.
+	 */
+	if (!isCommit)
+	{
+		PgStat_PendingRewrite **rewrite_ptr = &pending_rewrites;
+
+		while (*rewrite_ptr != NULL)
+		{
+			if ((*rewrite_ptr)->nest_level >= nestDepth)
+			{
+				PgStat_PendingRewrite *to_remove = *rewrite_ptr;
+
+				*rewrite_ptr = (*rewrite_ptr)->next;
+				pfree(to_remove);
+			}
+			else
+			{
+				rewrite_ptr = &((*rewrite_ptr)->next);
+			}
+		}
+	}
+
 	for (trans = xact_state->first; trans != NULL; trans = next_trans)
 	{
 		PgStat_TableStatus *tabstat;
@@ -760,11 +948,19 @@ void
 AtPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state)
 {
 	PgStat_TableXactStatus *trans;
+	PgStat_PendingRewrite *rewrite;
 
+	/*
+	 * For each tabstat, find its matching rewrite and remove it from the
+	 * pending rewrites list. This way, after processing all tabstats, pending
+	 * rewrites will only contain rewrite only transactions.
+	 */
 	for (trans = xact_state->first; trans != NULL; trans = trans->next)
 	{
 		PgStat_TableStatus *tabstat PG_USED_FOR_ASSERTS_ONLY;
 		TwoPhasePgStatRecord record;
+		PgStat_PendingRewrite **rewrite_ptr;
+		bool		found_rewrite = false;
 
 		Assert(trans->nest_level == 1);
 		Assert(trans->upper == NULL);
@@ -784,10 +980,83 @@ AtPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state)
 			record.locator = tabstat->locator;
 
 		record.truncdropped = trans->truncdropped;
+		record.rewrite_nest_level = 0;
+
+		/*
+		 * Look for a matching rewrite and remove it from pending rewrites. We
+		 * check three possible matches:
+		 *
+		 * The new_locator when stats have been added after the rewrite. The
+		 * old_locator when stats have been added before the rewrite but not
+		 * after. The original_locator when this tabstat is part of a rewrite
+		 * chain.
+		 */
+		rewrite_ptr = &pending_rewrites;
+		while (*rewrite_ptr != NULL)
+		{
+			rewrite = *rewrite_ptr;
+
+			if ((record.locator.dbOid == rewrite->new_locator.dbOid &&
+				 record.locator.spcOid == rewrite->new_locator.spcOid &&
+				 record.locator.relNumber == rewrite->new_locator.relNumber) ||
+				(tabstat->locator.dbOid == rewrite->old_locator.dbOid &&
+				 tabstat->locator.spcOid == rewrite->old_locator.spcOid &&
+				 tabstat->locator.relNumber == rewrite->old_locator.relNumber) ||
+				(tabstat->locator.dbOid == rewrite->original_locator.dbOid &&
+				 tabstat->locator.spcOid == rewrite->original_locator.spcOid &&
+				 tabstat->locator.relNumber == rewrite->original_locator.relNumber))
+			{
+				/*
+				 * Found matching rewrite. Record the rewrite information and
+				 * remove this rewrite from the list since it's now handled.
+				 */
+				record.rewrite_old_locator = rewrite->original_locator;
+				record.rewrite_nest_level = rewrite->nest_level;
+				record.locator = rewrite->new_locator;
+				found_rewrite = true;
+
+				/* Remove from pending_rewrites list */
+				*rewrite_ptr = rewrite->next;
+				pfree(rewrite);
+				break;
+			}
+			else
+			{
+				/* Move to next rewrite in the list */
+				rewrite_ptr = &(rewrite->next);
+			}
+		}
+
+		/* If no rewrite found, clear the rewrite fields */
+		if (!found_rewrite)
+		{
+			memset(&record.rewrite_old_locator, 0, sizeof(RelFileLocator));
+		}
+
+		RegisterTwoPhaseRecord(TWOPHASE_RM_PGSTAT_ID, 0,
+							   &record, sizeof(TwoPhasePgStatRecord));
+	}
+
+	/*
+	 * Now process any rewrites still pending. These are rewrite only
+	 * transactions. We need to preserve their stats even though there's no
+	 * tabstat entry for them.
+	 */
+	for (rewrite = pending_rewrites; rewrite != NULL; rewrite = rewrite->next)
+	{
+		TwoPhasePgStatRecord record;
+
+		memset(&record, 0, sizeof(TwoPhasePgStatRecord));
+		record.locator = rewrite->new_locator;
+		record.rewrite_old_locator = rewrite->original_locator;
+		record.rewrite_nest_level = rewrite->nest_level;
+		record.truncdropped = false;
 
 		RegisterTwoPhaseRecord(TWOPHASE_RM_PGSTAT_ID, 0,
 							   &record, sizeof(TwoPhasePgStatRecord));
 	}
+
+	pending_rewrites = NULL;
 }
 
 /*
@@ -810,6 +1079,8 @@ PostPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state)
 		tabstat = trans->parent;
 		tabstat->trans = NULL;
 	}
+
+	pending_rewrites = NULL;
 }
 
 /*
@@ -845,6 +1116,29 @@ pgstat_twophase_postcommit(FullTransactionId fxid, uint16 info,
 	pgstat_info->counts.changed_tuples +=
 		rec->tuples_inserted + rec->tuples_updated +
 		rec->tuples_deleted;
+
+	if (rec->rewrite_nest_level > 0)
+	{
+		PgStat_EntryRef *old_entry_ref;
+
+		/* Flush any pending stats for old locator first */
+		old_entry_ref = pgstat_fetch_pending_entry(PGSTAT_KIND_RELATION,
+												   rec->rewrite_old_locator.dbOid,
+												   RelFileLocatorToPgStatObjid(rec->rewrite_old_locator));
+
+		if (old_entry_ref && old_entry_ref->pending)
+			pgstat_relation_flush_cb(old_entry_ref, false);
+
+		/* Copy stats from old to new locator */
+		pgstat_copy_relation_stats(rec->locator, rec->rewrite_old_locator,
+								   true);
+
+		/* Drop old locator's stats */
+		if (!pgstat_drop_entry(PGSTAT_KIND_RELATION,
+							   rec->rewrite_old_locator.dbOid,
+							   RelFileLocatorToPgStatObjid(rec->rewrite_old_locator)))
+			pgstat_request_entry_refs_gc();
+	}
 }
 
 /*
@@ -859,9 +1153,26 @@ pgstat_twophase_postabort(FullTransactionId fxid, uint16 info,
 {
 	TwoPhasePgStatRecord *rec = (TwoPhasePgStatRecord *) recdata;
 	PgStat_TableStatus *pgstat_info;
+	RelFileLocator target_locator;
+
+	/*
+	 * For aborted transactions with rewrites (like TRUNCATE), we need to
+	 * restore stats to the old locator, not the new one. The new locator
+	 * should be dropped since the rewrite is being rolled back.
+	 */
+	if (rec->rewrite_nest_level > 0)
+	{
+		/* Use the old locator */
+		target_locator = rec->rewrite_old_locator;
+	}
+	else
+	{
+		/* No rewrite, use the original locator */
+		target_locator = rec->locator;
+	}
 
 	/* Find or create a tabstat entry for the target locator */
-	pgstat_info = pgstat_prep_relation_pending(rec->locator);
+	pgstat_info = pgstat_prep_relation_pending(target_locator);
 
 	/* Same math as in AtEOXact_PgStat, abort case */
 	if (rec->truncdropped)
@@ -916,7 +1227,17 @@ pgstat_relation_flush_cb(PgStat_EntryRef *entry_ref, bool nowait)
 	tabentry->numscans += lstats->counts.numscans;
 	if (lstats->counts.numscans)
 	{
-		TimestampTz t = GetCurrentTransactionStopTimestamp();
+		TimestampTz t;
+
+		/*
+		 * Checking the transaction state due to the flush call in
+		 * pgstat_twophase_postcommit() that would break the assertion on the
+		 * state in GetCurrentTransactionStopTimestamp().
+		 */
+		if (!IsTransactionState())
+			t = GetCurrentTransactionStopTimestamp();
+		else
+			t = GetCurrentTimestamp();
 
 		if (t > tabentry->lastscan)
 			tabentry->lastscan = t;
@@ -1167,3 +1488,45 @@ pgstat_reloid_to_relfilelocator(Oid reloid, RelFileLocator *locator)
 	ReleaseSysCache(tuple);
 	return result;
 }
+
+/*
+ * Mark that a relation rewrite has occurred, preserving the original locator
+ * so stats can be copied at transaction commit.
+ */
+void
+pgstat_mark_rewrite(RelFileLocator old_locator, RelFileLocator new_locator)
+{
+	PgStat_PendingRewrite *rewrite;
+	PgStat_PendingRewrite *existing;
+	RelFileLocator original_locator = old_locator;
+
+	for (existing = pending_rewrites; existing != NULL; existing = existing->next)
+	{
+		if (old_locator.dbOid == existing->new_locator.dbOid &&
+			old_locator.spcOid == existing->new_locator.spcOid &&
+			old_locator.relNumber == existing->new_locator.relNumber)
+		{
+			original_locator = existing->original_locator;
+			break;
+		}
+	}
+
+	/* Allocate in TopTransactionContext memory context */
+	rewrite = MemoryContextAlloc(TopTransactionContext,
+								 sizeof(PgStat_PendingRewrite));
+
+	rewrite->old_locator = old_locator;
+	rewrite->new_locator = new_locator;
+	rewrite->original_locator = original_locator;
+	rewrite->nest_level = GetCurrentTransactionNestLevel();
+
+	/* Add to the list */
+	rewrite->next = pending_rewrites;
+	pending_rewrites = rewrite;
+}
+
+void
+pgstat_clear_rewrite(void)
+{
+	pending_rewrites = NULL;
+}
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index bc9864bd8d9..f8cf3755ce2 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -55,6 +55,8 @@ AtEOXact_PgStat(bool isCommit, bool parallel)
 	}
 	pgStatXactStack = NULL;
 
+	pgstat_clear_rewrite();
+
 	/* Make sure any stats snapshot is thrown away */
 	pgstat_clear_snapshot();
 }
@@ -360,8 +362,29 @@ create_drop_transactional_internal(PgStat_Kind kind, Oid dboid, uint64 objid, bo
 void
 pgstat_create_transactional(PgStat_Kind kind, Oid dboid, uint64 objid)
 {
-	if (pgstat_get_entry_ref(kind, dboid, objid, false, NULL))
+	PgStat_EntryRef *entry_ref;
+
+	entry_ref = pgstat_get_entry_ref(kind, dboid, objid, false, NULL);
+
+	if (entry_ref)
 	{
+		/*
+		 * For relations stats, we key by physical file location, not by
+		 * relation OID. This means during operations like ALTER TYPE where
+		 * the relation OID changes but the relfilenode stays the same (no
+		 * actual rewrite needed), we'll find an existing entry.
+		 *
+		 * This is expected behavior, we want to preserve stats across the
+		 * catalog change. Simply reset and recreate the entry for the new
+		 * relation OID without warning.
+		 */
+		if (kind == PGSTAT_KIND_RELATION)
+		{
+			pgstat_reset(kind, dboid, objid);
+			create_drop_transactional_internal(kind, dboid, objid, true);
+			return;
+		}
+
 		ereport(WARNING,
 				errmsg("resetting existing statistics for kind %s, db=%u, oid=%" PRIu64,
 					   (pgstat_get_kind_info(kind))->name, dboid,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 2d0cb7bcfd4..c98e5c51d63 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -85,6 +85,7 @@
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
+#include "utils/pgstat_internal.h"
 #include "utils/relmapper.h"
 #include "utils/resowner.h"
 #include "utils/snapmgr.h"
@@ -3780,6 +3781,7 @@ RelationSetNewRelfilenumber(Relation relation, char persistence)
 	MultiXactId minmulti = InvalidMultiXactId;
 	TransactionId freezeXid = InvalidTransactionId;
 	RelFileLocator newrlocator;
+	RelFileLocator oldrlocator = relation->rd_locator;
 
 	if (!IsBinaryUpgrade)
 	{
@@ -3951,6 +3953,10 @@ RelationSetNewRelfilenumber(Relation relation, char persistence)
 
 	table_close(pg_class, RowExclusiveLock);
 
+	/* Mark that a rewrite happened */
+	if (RELKIND_HAS_STORAGE(relation->rd_rel->relkind))
+		pgstat_mark_rewrite(oldrlocator, newrlocator);
+
 	/*
 	 * Make the pg_class row change or relation map change visible.  This will
 	 * cause the relcache entry to get updated, too.
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 3102f86aa24..8750c025bbe 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -670,7 +670,7 @@ extern PgStat_FunctionCounts *find_funcstat_entry(Oid func_id);
 
 extern void pgstat_create_relation(Relation rel);
 extern void pgstat_drop_relation(Relation rel);
-extern void pgstat_copy_relation_stats(Relation dst, Relation src);
+extern void pgstat_copy_relation_stats(RelFileLocator dst, RelFileLocator src, bool increment);
 
 extern void pgstat_init_relation(Relation rel);
 extern void pgstat_assoc_relation(Relation rel);
@@ -682,6 +682,9 @@ extern void pgstat_report_vacuum(Relation rel, PgStat_Counter livetuples,
 extern void pgstat_report_analyze(Relation rel,
 								  PgStat_Counter livetuples, PgStat_Counter deadtuples,
 								  bool resetcounter, TimestampTz starttime);
+extern void pgstat_mark_rewrite(RelFileLocator old_locator,
+								RelFileLocator new_locator);
+extern void pgstat_clear_rewrite(void);
 
 /*
  * If stats are enabled, but pending data hasn't been prepared yet, call
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 04845d5e680..3184e9c464b 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2269,6 +2269,7 @@ PgStat_KindInfo
 PgStat_LocalState
 PgStat_PendingDroppedStatsItem
 PgStat_PendingIO
+PgStat_PendingRewrite
 PgStat_SLRUStats
 PgStat_ShmemControl
 PgStat_Snapshot
-- 
2.34.1


--xJsrX25x3tm7Tn81--





^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* [PATCH v6 04/14] bufmgr: Change BufferDesc.state to be a 64bit atomic
@ 2025-11-06 00:22  Andres Freund <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Andres Freund @ 2025-11-06 00:22 UTC (permalink / raw)

This is motivated by wanting to merge buffer content locks into
BufferDesc.state in a future commit, rather than having a separate lwlock (see
commit c75ebc657ff more details). As this change is rather mechanical, it
seems to make sense to split it out into a separate commit, for easier review.

Discussion: https://postgr.es/m/fvfmkr5kk4nyex56ejgxj3uzi63isfxovp2biecb4bspbjrze7@az2pljabhnff
---
 src/include/storage/buf_internals.h           |  88 ++++++----
 src/backend/storage/buffer/buf_init.c         |   2 +-
 src/backend/storage/buffer/bufmgr.c           | 158 +++++++++---------
 src/backend/storage/buffer/freelist.c         |  24 +--
 src/backend/storage/buffer/localbuf.c         |  72 ++++----
 contrib/pg_buffercache/pg_buffercache_pages.c |   8 +-
 src/test/modules/test_aio/test_aio.c          |  12 +-
 7 files changed, 192 insertions(+), 172 deletions(-)

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index 5400c56a965..28519ad2813 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -30,7 +30,7 @@
 #include "utils/resowner.h"
 
 /*
- * Buffer state is a single 32-bit variable where following data is combined.
+ * Buffer state is a single 64-bit variable where following data is combined.
  *
  * - 18 bits refcount
  * - 4 bits usage count
@@ -39,6 +39,9 @@
  * Combining these values allows to perform some operations without locking
  * the buffer header, by modifying them together with a CAS loop.
  *
+ * NB: A future commit will use a significant portion of the remaining bits to
+ * implement buffer locking as part of the state variable.
+ *
  * The definition of buffer state components is below.
  */
 #define BUF_REFCOUNT_BITS 18
@@ -49,15 +52,21 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
 				 "parts of buffer state space need to equal 32");
 
 #define BUF_REFCOUNT_ONE 1
-#define BUF_REFCOUNT_MASK ((1U << BUF_REFCOUNT_BITS) - 1)
-#define BUF_USAGECOUNT_MASK (((1U << BUF_USAGECOUNT_BITS) - 1) << (BUF_REFCOUNT_BITS))
-#define BUF_USAGECOUNT_ONE (1U << BUF_REFCOUNT_BITS)
+#define BUF_REFCOUNT_MASK \
+	((UINT64CONST(1) << BUF_REFCOUNT_BITS) - 1)
+#define BUF_USAGECOUNT_MASK \
+	(((UINT64CONST(1) << BUF_USAGECOUNT_BITS) - 1) << (BUF_REFCOUNT_BITS))
+#define BUF_USAGECOUNT_ONE \
+	(UINT64CONST(1) << BUF_REFCOUNT_BITS)
 #define BUF_USAGECOUNT_SHIFT BUF_REFCOUNT_BITS
-#define BUF_FLAG_MASK (((1U << BUF_FLAG_BITS) - 1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS))
+#define BUF_FLAG_MASK \
+	(((UINT64CONST(1) << BUF_FLAG_BITS) - 1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS))
 
 /* Get refcount and usagecount from buffer state */
-#define BUF_STATE_GET_REFCOUNT(state) ((state) & BUF_REFCOUNT_MASK)
-#define BUF_STATE_GET_USAGECOUNT(state) (((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT)
+#define BUF_STATE_GET_REFCOUNT(state) \
+	((uint32)((state) & BUF_REFCOUNT_MASK))
+#define BUF_STATE_GET_USAGECOUNT(state) \
+	((uint32)(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT))
 
 /*
  * Flags for buffer descriptors
@@ -65,17 +74,28 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  * Note: BM_TAG_VALID essentially means that there is a buffer hashtable
  * entry associated with the buffer's tag.
  */
-#define BM_LOCKED				(1U << 22)	/* buffer header is locked */
-#define BM_DIRTY				(1U << 23)	/* data needs writing */
-#define BM_VALID				(1U << 24)	/* data is valid */
-#define BM_TAG_VALID			(1U << 25)	/* tag is assigned */
-#define BM_IO_IN_PROGRESS		(1U << 26)	/* read or write in progress */
-#define BM_IO_ERROR				(1U << 27)	/* previous I/O failed */
-#define BM_JUST_DIRTIED			(1U << 28)	/* dirtied since write started */
-#define BM_PIN_COUNT_WAITER		(1U << 29)	/* have waiter for sole pin */
-#define BM_CHECKPOINT_NEEDED	(1U << 30)	/* must write for checkpoint */
-#define BM_PERMANENT			(1U << 31)	/* permanent buffer (not unlogged,
-											 * or init fork) */
+
+/* buffer header is locked */
+#define BM_LOCKED				(UINT64CONST(1) << 22)
+/* data needs writing */
+#define BM_DIRTY				(UINT64CONST(1) << 23)
+/* data is valid */
+#define BM_VALID				(UINT64CONST(1) << 24)
+/* tag is assigned */
+#define BM_TAG_VALID			(UINT64CONST(1) << 25)
+/* read or write in progress */
+#define BM_IO_IN_PROGRESS		(UINT64CONST(1) << 26)
+/* previous I/O failed */
+#define BM_IO_ERROR				(UINT64CONST(1) << 27)
+/* dirtied since write started */
+#define BM_JUST_DIRTIED			(UINT64CONST(1) << 28)
+/* have waiter for sole pin */
+#define BM_PIN_COUNT_WAITER		(UINT64CONST(1) << 29)
+/* must write for checkpoint */
+#define BM_CHECKPOINT_NEEDED	(UINT64CONST(1) << 30)
+/* permanent buffer (not unlogged, or init fork) */
+#define BM_PERMANENT			(UINT64CONST(1) << 31)
+
 /*
  * The maximum allowed value of usage_count represents a tradeoff between
  * accuracy and speed of the clock-sweep buffer management algorithm.  A
@@ -86,7 +106,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 #define BM_MAX_USAGE_COUNT	5
 
-StaticAssertDecl(BM_MAX_USAGE_COUNT < (1 << BUF_USAGECOUNT_BITS),
+StaticAssertDecl(BM_MAX_USAGE_COUNT < (UINT64CONST(1) << BUF_USAGECOUNT_BITS),
 				 "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
 StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
 				 "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
@@ -251,8 +271,8 @@ BufMappingPartitionLockByIndex(uint32 index)
  * We use this same struct for local buffer headers, but the locks are not
  * used and not all of the flag bits are useful either. To avoid unnecessary
  * overhead, manipulations of the state field should be done without actual
- * atomic operations (i.e. only pg_atomic_read_u32() and
- * pg_atomic_unlocked_write_u32()).
+ * atomic operations (i.e. only pg_atomic_read_u64() and
+ * pg_atomic_unlocked_write_u64()).
  *
  * Be careful to avoid increasing the size of the struct when adding or
  * reordering members.  Keeping it below 64 bytes (the most common CPU
@@ -280,7 +300,7 @@ typedef struct BufferDesc
 	 * State of the buffer, containing flags, refcount and usagecount. See
 	 * BUF_* and BM_* defines at the top of this file.
 	 */
-	pg_atomic_uint32 state;
+	pg_atomic_uint64 state;
 
 	/*
 	 * Backend of pin-count waiter. The buffer header spinlock needs to be
@@ -386,7 +406,7 @@ BufferDescriptorGetContentLock(const BufferDesc *bdesc)
  * Functions for acquiring/releasing a shared buffer header's spinlock.  Do
  * not apply these to local buffers!
  */
-extern uint32 LockBufHdr(BufferDesc *desc);
+extern uint64 LockBufHdr(BufferDesc *desc);
 
 /*
  * Unlock the buffer header.
@@ -397,9 +417,9 @@ extern uint32 LockBufHdr(BufferDesc *desc);
 static inline void
 UnlockBufHdr(BufferDesc *desc)
 {
-	Assert(pg_atomic_read_u32(&desc->state) & BM_LOCKED);
+	Assert(pg_atomic_read_u64(&desc->state) & BM_LOCKED);
 
-	pg_atomic_fetch_sub_u32(&desc->state, BM_LOCKED);
+	pg_atomic_fetch_sub_u64(&desc->state, BM_LOCKED);
 }
 
 /*
@@ -410,14 +430,14 @@ UnlockBufHdr(BufferDesc *desc)
  * Note that this approach would not work for usagecount, since we need to cap
  * the usagecount at BM_MAX_USAGE_COUNT.
  */
-static inline uint32
-UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
-				uint32 set_bits, uint32 unset_bits,
+static inline uint64
+UnlockBufHdrExt(BufferDesc *desc, uint64 old_buf_state,
+				uint64 set_bits, uint64 unset_bits,
 				int refcount_change)
 {
 	for (;;)
 	{
-		uint32		buf_state = old_buf_state;
+		uint64		buf_state = old_buf_state;
 
 		Assert(buf_state & BM_LOCKED);
 
@@ -428,7 +448,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 		if (refcount_change != 0)
 			buf_state += BUF_REFCOUNT_ONE * refcount_change;
 
-		if (pg_atomic_compare_exchange_u32(&desc->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&desc->state, &old_buf_state,
 										   buf_state))
 		{
 			return old_buf_state;
@@ -436,7 +456,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 	}
 }
 
-extern uint32 WaitBufHdrUnlocked(BufferDesc *buf);
+extern uint64 WaitBufHdrUnlocked(BufferDesc *buf);
 
 /* in bufmgr.c */
 
@@ -496,14 +516,14 @@ extern void TrackNewBufferPin(Buffer buf);
 
 /* solely to make it easier to write tests */
 extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
-extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 							  bool forget_owner, bool release_aio);
 
 
 /* freelist.c */
 extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
 extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
-									 uint32 *buf_state, bool *from_ring);
+									 uint64 *buf_state, bool *from_ring);
 extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
 								 BufferDesc *buf, bool from_ring);
 
@@ -539,7 +559,7 @@ extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
 										  uint32 *extended_by);
 extern void MarkLocalBufferDirty(Buffer buffer);
 extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
-								   uint32 set_flag_bits, bool release_aio);
+								   uint64 set_flag_bits, bool release_aio);
 extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
 extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
 extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
diff --git a/src/backend/storage/buffer/buf_init.c b/src/backend/storage/buffer/buf_init.c
index 6fd3a6bbac5..25f71191ec3 100644
--- a/src/backend/storage/buffer/buf_init.c
+++ b/src/backend/storage/buffer/buf_init.c
@@ -121,7 +121,7 @@ BufferManagerShmemInit(void)
 
 			ClearBufferTag(&buf->tag);
 
-			pg_atomic_init_u32(&buf->state, 0);
+			pg_atomic_init_u64(&buf->state, 0);
 			buf->wait_backend_pgprocno = INVALID_PROC_NUMBER;
 
 			buf->buf_id = i;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index b682878b1fb..e33fa0cbfec 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -686,7 +686,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 {
 	BufferDesc *bufHdr;
 	BufferTag	tag;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(recent_buffer));
 
@@ -699,7 +699,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 		int			b = -recent_buffer - 1;
 
 		bufHdr = GetLocalBufferDescriptor(b);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		/* Is it still valid and holding the right tag? */
 		if ((buf_state & BM_VALID) && BufferTagsEqual(&tag, &bufHdr->tag))
@@ -1292,8 +1292,8 @@ StartReadBuffersImpl(ReadBuffersOperation *operation,
 				bufHdr = GetLocalBufferDescriptor(-buffers[i] - 1);
 			else
 				bufHdr = GetBufferDescriptor(buffers[i] - 1);
-			Assert(pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID);
-			found = pg_atomic_read_u32(&bufHdr->state) & BM_VALID;
+			Assert(pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID);
+			found = pg_atomic_read_u64(&bufHdr->state) & BM_VALID;
 		}
 		else
 		{
@@ -1519,10 +1519,10 @@ CheckReadBuffersOperation(ReadBuffersOperation *operation, bool is_complete)
 			GetBufferDescriptor(buffer - 1);
 
 		Assert(BufferGetBlockNumber(buffer) == operation->blocknum + i);
-		Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_TAG_VALID);
+		Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_TAG_VALID);
 
 		if (i < operation->nblocks_done)
-			Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_VALID);
+			Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_VALID);
 	}
 #endif
 }
@@ -1989,8 +1989,8 @@ BufferAlloc(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 	int			existing_buf_id;
 	Buffer		victim_buffer;
 	BufferDesc *victim_buf_hdr;
-	uint32		victim_buf_state;
-	uint32		set_bits = 0;
+	uint64		victim_buf_state;
+	uint64		set_bits = 0;
 
 	/* Make sure we will have room to remember the buffer pin */
 	ResourceOwnerEnlarge(CurrentResourceOwner);
@@ -2157,7 +2157,7 @@ InvalidateBuffer(BufferDesc *buf)
 	uint32		oldHash;		/* hash value for oldTag */
 	LWLock	   *oldPartitionLock;	/* buffer partition lock for it */
 	uint32		oldFlags;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/* Save the original buffer tag before dropping the spinlock */
 	oldTag = buf->tag;
@@ -2248,7 +2248,7 @@ retry:
 static bool
 InvalidateVictimBuffer(BufferDesc *buf_hdr)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	uint32		hash;
 	LWLock	   *partition_lock;
 	BufferTag	tag;
@@ -2308,10 +2308,10 @@ InvalidateVictimBuffer(BufferDesc *buf_hdr)
 
 	LWLockRelease(partition_lock);
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	Assert(!(buf_state & (BM_DIRTY | BM_VALID | BM_TAG_VALID)));
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
-	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u32(&buf_hdr->state)) > 0);
+	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u64(&buf_hdr->state)) > 0);
 
 	return true;
 }
@@ -2321,7 +2321,7 @@ GetVictimBuffer(BufferAccessStrategy strategy, IOContext io_context)
 {
 	BufferDesc *buf_hdr;
 	Buffer		buf;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		from_ring;
 
 	/*
@@ -2454,7 +2454,7 @@ again:
 
 	/* a final set of sanity checks */
 #ifdef USE_ASSERT_CHECKING
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) == 1);
 	Assert(!(buf_state & (BM_TAG_VALID | BM_VALID | BM_DIRTY)));
@@ -2745,13 +2745,13 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
 			 */
 			do
 			{
-				pg_atomic_fetch_and_u32(&existing_hdr->state, ~BM_VALID);
+				pg_atomic_fetch_and_u64(&existing_hdr->state, ~BM_VALID);
 			} while (!StartBufferIO(existing_hdr, true, false));
 		}
 		else
 		{
-			uint32		buf_state;
-			uint32		set_bits = 0;
+			uint64		buf_state;
+			uint64		set_bits = 0;
 
 			buf_state = LockBufHdr(victim_buf_hdr);
 
@@ -2927,7 +2927,7 @@ BufferIsDirty(Buffer buffer)
 		Assert(BufferIsLockedByMeInMode(buffer, BUFFER_LOCK_EXCLUSIVE));
 	}
 
-	return pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY;
+	return pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY;
 }
 
 /*
@@ -2943,8 +2943,8 @@ void
 MarkBufferDirty(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
-	uint32		old_buf_state;
+	uint64		buf_state;
+	uint64		old_buf_state;
 
 	if (!BufferIsValid(buffer))
 		elog(ERROR, "bad buffer ID: %d", buffer);
@@ -2964,7 +2964,7 @@ MarkBufferDirty(Buffer buffer)
 	 * NB: We have to wait for the buffer header spinlock to be not held, as
 	 * TerminateBufferIO() relies on the spinlock.
 	 */
-	old_buf_state = pg_atomic_read_u32(&bufHdr->state);
+	old_buf_state = pg_atomic_read_u64(&bufHdr->state);
 	for (;;)
 	{
 		if (old_buf_state & BM_LOCKED)
@@ -2975,7 +2975,7 @@ MarkBufferDirty(Buffer buffer)
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state |= BM_DIRTY | BM_JUST_DIRTIED;
 
-		if (pg_atomic_compare_exchange_u32(&bufHdr->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&bufHdr->state, &old_buf_state,
 										   buf_state))
 			break;
 	}
@@ -3079,10 +3079,10 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 
 	if (ref == NULL)
 	{
-		uint32		buf_state;
-		uint32		old_buf_state;
+		uint64		buf_state;
+		uint64		old_buf_state;
 
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			if (unlikely(skip_if_not_valid && !(old_buf_state & BM_VALID)))
@@ -3116,7 +3116,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 					buf_state += BUF_USAGECOUNT_ONE;
 			}
 
-			if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+			if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 											   buf_state))
 			{
 				result = (buf_state & BM_VALID) != 0;
@@ -3143,7 +3143,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 		 * that the buffer page is legitimately non-accessible here.  We
 		 * cannot meddle with that.
 		 */
-		result = (pg_atomic_read_u32(&buf->state) & BM_VALID) != 0;
+		result = (pg_atomic_read_u64(&buf->state) & BM_VALID) != 0;
 
 		Assert(ref->refcount > 0);
 		ref->refcount++;
@@ -3178,7 +3178,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 static void
 PinBuffer_Locked(BufferDesc *buf)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	/*
 	 * As explained, We don't expect any preexisting pins. That allows us to
@@ -3190,7 +3190,7 @@ PinBuffer_Locked(BufferDesc *buf)
 	 * Since we hold the buffer spinlock, we can update the buffer state and
 	 * release the lock in one operation.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 
 	UnlockBufHdrExt(buf, old_buf_state,
 					0, 0, 1);
@@ -3220,7 +3220,7 @@ WakePinCountWaiter(BufferDesc *buf)
 	 * BM_PIN_COUNT_WAITER if it stops waiting for a reason other than this
 	 * backend waking it up.
 	 */
-	uint32		buf_state = LockBufHdr(buf);
+	uint64		buf_state = LockBufHdr(buf);
 
 	if ((buf_state & BM_PIN_COUNT_WAITER) &&
 		BUF_STATE_GET_REFCOUNT(buf_state) == 1)
@@ -3267,7 +3267,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 	ref->refcount--;
 	if (ref->refcount == 0)
 	{
-		uint32		old_buf_state;
+		uint64		old_buf_state;
 
 		/*
 		 * Mark buffer non-accessible to Valgrind.
@@ -3285,7 +3285,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 		Assert(!LWLockHeldByMe(BufferDescriptorGetContentLock(buf)));
 
 		/* decrement the shared reference count */
-		old_buf_state = pg_atomic_fetch_sub_u32(&buf->state, BUF_REFCOUNT_ONE);
+		old_buf_state = pg_atomic_fetch_sub_u64(&buf->state, BUF_REFCOUNT_ONE);
 
 		/* Support LockBufferForCleanup() */
 		if (old_buf_state & BM_PIN_COUNT_WAITER)
@@ -3342,7 +3342,7 @@ TrackNewBufferPin(Buffer buf)
 static void
 BufferSync(int flags)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	int			buf_id;
 	int			num_to_scan;
 	int			num_spaces;
@@ -3352,7 +3352,7 @@ BufferSync(int flags)
 	Oid			last_tsid;
 	binaryheap *ts_heap;
 	int			i;
-	uint32		mask = BM_DIRTY;
+	uint64		mask = BM_DIRTY;
 	WritebackContext wb_context;
 
 	/*
@@ -3384,7 +3384,7 @@ BufferSync(int flags)
 	for (buf_id = 0; buf_id < NBuffers; buf_id++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
-		uint32		set_bits = 0;
+		uint64		set_bits = 0;
 
 		/*
 		 * Header spinlock is enough to examine BM_DIRTY, see comment in
@@ -3551,7 +3551,7 @@ BufferSync(int flags)
 		 * write the buffer though we didn't need to.  It doesn't seem worth
 		 * guarding against this, though.
 		 */
-		if (pg_atomic_read_u32(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
+		if (pg_atomic_read_u64(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
 		{
 			if (SyncOneBuffer(buf_id, false, &wb_context) & BUF_WRITTEN)
 			{
@@ -3921,7 +3921,7 @@ SyncOneBuffer(int buf_id, bool skip_recently_used, WritebackContext *wb_context)
 {
 	BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
 	int			result = 0;
-	uint32		buf_state;
+	uint64		buf_state;
 	BufferTag	tag;
 
 	/* Make sure we can handle the pin */
@@ -4169,7 +4169,7 @@ DebugPrintBufferRefcount(Buffer buffer)
 	int32		loccount;
 	char	   *result;
 	ProcNumber	backend;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
@@ -4186,9 +4186,9 @@ DebugPrintBufferRefcount(Buffer buffer)
 	}
 
 	/* theoretically we should lock the bufhdr here */
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
-	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
+	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%" PRIx64 ", refcount=%u %d)",
 					  buffer,
 					  relpathbackend(BufTagGetRelFileLocator(&buf->tag), backend,
 									 BufTagGetForkNum(&buf->tag)).str,
@@ -4288,7 +4288,7 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
 	instr_time	io_start;
 	Block		bufBlock;
 	char	   *bufToWrite;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * Try to start an I/O operation.  If StartBufferIO returns false, then
@@ -4486,7 +4486,7 @@ BufferIsPermanent(Buffer buffer)
 	 * not random garbage.
 	 */
 	bufHdr = GetBufferDescriptor(buffer - 1);
-	return (pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT) != 0;
+	return (pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT) != 0;
 }
 
 /*
@@ -4949,11 +4949,11 @@ FlushRelationBuffers(Relation rel)
 	{
 		for (i = 0; i < NLocBuffer; i++)
 		{
-			uint32		buf_state;
+			uint64		buf_state;
 
 			bufHdr = GetLocalBufferDescriptor(i);
 			if (BufTagMatchesRelFileLocator(&bufHdr->tag, &rel->rd_locator) &&
-				((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
+				((buf_state = pg_atomic_read_u64(&bufHdr->state)) &
 				 (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
 			{
 				ErrorContextCallback errcallback;
@@ -4989,7 +4989,7 @@ FlushRelationBuffers(Relation rel)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5061,7 +5061,7 @@ FlushRelationsAllBuffers(SMgrRelation *smgrs, int nrels)
 	{
 		SMgrSortArray *srelent = NULL;
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * As in DropRelationBuffers, an unlocked precheck should be safe and
@@ -5310,7 +5310,7 @@ FlushDatabaseBuffers(Oid dbid)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5458,13 +5458,13 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 	 * is only intended to be used in cases where failing to write out the
 	 * data would be harmless anyway, it doesn't really matter.
 	 */
-	if ((pg_atomic_read_u32(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
+	if ((pg_atomic_read_u64(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
 		(BM_DIRTY | BM_JUST_DIRTIED))
 	{
 		XLogRecPtr	lsn = InvalidXLogRecPtr;
 		bool		dirtied = false;
 		bool		delayChkptFlags = false;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * If we need to protect hint bit updates from torn writes, WAL-log a
@@ -5476,7 +5476,7 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 		 * when we call XLogInsert() since the value changes dynamically.
 		 */
 		if (XLogHintBitIsNeeded() &&
-			(pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT))
+			(pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT))
 		{
 			/*
 			 * If we must not write WAL, due to a relfilelocator-specific
@@ -5576,8 +5576,8 @@ UnlockBuffers(void)
 
 	if (buf)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		buf_state = LockBufHdr(buf);
 
@@ -5708,8 +5708,8 @@ LockBufferForCleanup(Buffer buffer)
 
 	for (;;)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -5857,7 +5857,7 @@ bool
 ConditionalLockBufferForCleanup(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state,
+	uint64		buf_state,
 				refcount;
 
 	Assert(BufferIsValid(buffer));
@@ -5915,7 +5915,7 @@ bool
 IsBufferCleanupOK(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 
@@ -5971,7 +5971,7 @@ WaitIO(BufferDesc *buf)
 	ConditionVariablePrepareToSleep(cv);
 	for (;;)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 		PgAioWaitRef iow;
 
 		/*
@@ -6045,7 +6045,7 @@ WaitIO(BufferDesc *buf)
 bool
 StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	ResourceOwnerEnlarge(CurrentResourceOwner);
 
@@ -6101,11 +6101,11 @@ StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
  * is being released)
  */
 void
-TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 				  bool forget_owner, bool release_aio)
 {
-	uint32		buf_state;
-	uint32		unset_flag_bits = 0;
+	uint64		buf_state;
+	uint64		unset_flag_bits = 0;
 	int			refcount_change = 0;
 
 	buf_state = LockBufHdr(buf);
@@ -6166,7 +6166,7 @@ static void
 AbortBufferIO(Buffer buffer)
 {
 	BufferDesc *buf_hdr = GetBufferDescriptor(buffer - 1);
-	uint32		buf_state;
+	uint64		buf_state;
 
 	buf_state = LockBufHdr(buf_hdr);
 	Assert(buf_state & (BM_IO_IN_PROGRESS | BM_TAG_VALID));
@@ -6260,11 +6260,11 @@ rlocator_comparator(const void *p1, const void *p2)
 /*
  * Lock buffer header - set BM_LOCKED in buffer state.
  */
-uint32
+uint64
 LockBufHdr(BufferDesc *desc)
 {
 	SpinDelayStatus delayStatus;
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	Assert(!BufferIsLocal(BufferDescriptorGetBuffer(desc)));
 
@@ -6273,7 +6273,7 @@ LockBufHdr(BufferDesc *desc)
 	while (true)
 	{
 		/* set BM_LOCKED flag */
-		old_buf_state = pg_atomic_fetch_or_u32(&desc->state, BM_LOCKED);
+		old_buf_state = pg_atomic_fetch_or_u64(&desc->state, BM_LOCKED);
 		/* if it wasn't set before we're OK */
 		if (!(old_buf_state & BM_LOCKED))
 			break;
@@ -6290,20 +6290,20 @@ LockBufHdr(BufferDesc *desc)
  * Obviously the buffer could be locked by the time the value is returned, so
  * this is primarily useful in CAS style loops.
  */
-pg_noinline uint32
+pg_noinline uint64
 WaitBufHdrUnlocked(BufferDesc *buf)
 {
 	SpinDelayStatus delayStatus;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	init_local_spin_delay(&delayStatus);
 
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
 	while (buf_state & BM_LOCKED)
 	{
 		perform_spin_delay(&delayStatus);
-		buf_state = pg_atomic_read_u32(&buf->state);
+		buf_state = pg_atomic_read_u64(&buf->state);
 	}
 
 	finish_spin_delay(&delayStatus);
@@ -6591,12 +6591,12 @@ ResOwnerPrintBufferPin(Datum res)
 static bool
 EvictUnpinnedBufferInternal(BufferDesc *desc, bool *buffer_flushed)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result;
 
 	*buffer_flushed = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -6690,12 +6690,12 @@ EvictAllUnpinnedBuffers(int32 *buffers_evicted, int32 *buffers_flushed,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -6742,7 +6742,7 @@ EvictRelUnpinnedBuffers(Relation rel, int32 *buffers_evicted,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
@@ -6809,7 +6809,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		BufferDesc *buf_hdr = is_temp ?
 			GetLocalBufferDescriptor(-buffer - 1)
 			: GetBufferDescriptor(buffer - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * Check that all the buffers are actually ones that could conceivably
@@ -6827,7 +6827,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		}
 
 		if (is_temp)
-			buf_state = pg_atomic_read_u32(&buf_hdr->state);
+			buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		else
 			buf_state = LockBufHdr(buf_hdr);
 
@@ -6865,7 +6865,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		if (is_temp)
 		{
 			buf_state += BUF_REFCOUNT_ONE;
-			pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 		}
 		else
 			UnlockBufHdrExt(buf_hdr, buf_state, 0, 0, 1);
@@ -7051,13 +7051,13 @@ buffer_readv_complete_one(PgAioTargetData *td, uint8 buf_off, Buffer buffer,
 		: GetBufferDescriptor(buffer - 1);
 	BufferTag	tag = buf_hdr->tag;
 	char	   *bufdata = BufferGetBlock(buffer);
-	uint32		set_flag_bits;
+	uint64		set_flag_bits;
 	int			piv_flags;
 
 	/* check that the buffer is in the expected state for a read */
 #ifdef USE_ASSERT_CHECKING
 	{
-		uint32		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 		Assert(buf_state & BM_TAG_VALID);
 		Assert(!(buf_state & BM_VALID));
diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 28d952b3534..1d4f19a9afd 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -86,7 +86,7 @@ typedef struct BufferAccessStrategyData
 
 /* Prototypes for internal functions */
 static BufferDesc *GetBufferFromRing(BufferAccessStrategy strategy,
-									 uint32 *buf_state);
+									 uint64 *buf_state);
 static void AddBufferToRing(BufferAccessStrategy strategy,
 							BufferDesc *buf);
 
@@ -171,7 +171,7 @@ ClockSweepTick(void)
  *	before returning.
  */
 BufferDesc *
-StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_ring)
+StrategyGetBuffer(BufferAccessStrategy strategy, uint64 *buf_state, bool *from_ring)
 {
 	BufferDesc *buf;
 	int			bgwprocno;
@@ -230,8 +230,8 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 	trycounter = NBuffers;
 	for (;;)
 	{
-		uint32		old_buf_state;
-		uint32		local_buf_state;
+		uint64		old_buf_state;
+		uint64		local_buf_state;
 
 		buf = GetBufferDescriptor(ClockSweepTick());
 
@@ -239,7 +239,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 		 * Check whether the buffer can be used and pin it if so. Do this
 		 * using a CAS loop, to avoid having to lock the buffer header.
 		 */
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			local_buf_state = old_buf_state;
@@ -277,7 +277,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 			{
 				local_buf_state -= BUF_USAGECOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					trycounter = NBuffers;
@@ -289,7 +289,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 				/* pin the buffer if the CAS succeeds */
 				local_buf_state += BUF_REFCOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					/* Found a usable buffer */
@@ -655,12 +655,12 @@ FreeAccessStrategy(BufferAccessStrategy strategy)
  * returning.
  */
 static BufferDesc *
-GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
+GetBufferFromRing(BufferAccessStrategy strategy, uint64 *buf_state)
 {
 	BufferDesc *buf;
 	Buffer		bufnum;
-	uint32		old_buf_state;
-	uint32		local_buf_state;	/* to avoid repeated (de-)referencing */
+	uint64		old_buf_state;
+	uint64		local_buf_state;	/* to avoid repeated (de-)referencing */
 
 
 	/* Advance to next ring slot */
@@ -682,7 +682,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 	 * Check whether the buffer can be used and pin it if so. Do this using a
 	 * CAS loop, to avoid having to lock the buffer header.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 	for (;;)
 	{
 		local_buf_state = old_buf_state;
@@ -710,7 +710,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 		/* pin the buffer if the CAS succeeds */
 		local_buf_state += BUF_REFCOUNT_ONE;
 
-		if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 										   local_buf_state))
 		{
 			*buf_state = local_buf_state;
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 15aac7d1c9f..a41a5facd3a 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -148,7 +148,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	}
 	else
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		victim_buffer = GetLocalVictimBuffer();
 		bufid = -victim_buffer - 1;
@@ -165,10 +165,10 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		 */
 		bufHdr->tag = newTag;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		buf_state &= ~(BUF_FLAG_MASK | BUF_USAGECOUNT_MASK);
 		buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 		*foundPtr = false;
 	}
@@ -245,12 +245,12 @@ GetLocalVictimBuffer(void)
 
 		if (LocalRefCount[victim_bufid] == 0)
 		{
-			uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 			if (BUF_STATE_GET_USAGECOUNT(buf_state) > 0)
 			{
 				buf_state -= BUF_USAGECOUNT_ONE;
-				pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+				pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 				trycounter = NLocBuffer;
 			}
 			else if (BUF_STATE_GET_REFCOUNT(buf_state) > 0)
@@ -286,13 +286,13 @@ GetLocalVictimBuffer(void)
 	 * this buffer is not referenced but it might still be dirty. if that's
 	 * the case, write it out before reusing it!
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY)
 		FlushLocalBuffer(bufHdr, NULL);
 
 	/*
 	 * Remove the victim buffer from the hashtable and mark as invalid.
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID)
 	{
 		InvalidateLocalBuffer(bufHdr, false);
 
@@ -417,7 +417,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 		if (found)
 		{
 			BufferDesc *existing_hdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			UnpinLocalBuffer(BufferDescriptorGetBuffer(victim_buf_hdr));
 
@@ -428,18 +428,18 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 			/*
 			 * Clear the BM_VALID bit, do StartLocalBufferIO() and proceed.
 			 */
-			buf_state = pg_atomic_read_u32(&existing_hdr->state);
+			buf_state = pg_atomic_read_u64(&existing_hdr->state);
 			Assert(buf_state & BM_TAG_VALID);
 			Assert(!(buf_state & BM_DIRTY));
 			buf_state &= ~BM_VALID;
-			pg_atomic_unlocked_write_u32(&existing_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&existing_hdr->state, buf_state);
 
 			/* no need to loop for local buffers */
 			StartLocalBufferIO(existing_hdr, true, false);
 		}
 		else
 		{
-			uint32		buf_state = pg_atomic_read_u32(&victim_buf_hdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&victim_buf_hdr->state);
 
 			Assert(!(buf_state & (BM_VALID | BM_TAG_VALID | BM_DIRTY | BM_JUST_DIRTIED)));
 
@@ -447,7 +447,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 
 			buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
 
-			pg_atomic_unlocked_write_u32(&victim_buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&victim_buf_hdr->state, buf_state);
 
 			hresult->id = victim_buf_id;
 
@@ -467,13 +467,13 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 	{
 		Buffer		buf = buffers[i];
 		BufferDesc *buf_hdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		buf_state |= BM_VALID;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 
 	*extended_by = extend_by;
@@ -492,7 +492,7 @@ MarkLocalBufferDirty(Buffer buffer)
 {
 	int			bufid;
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsLocal(buffer));
 
@@ -506,14 +506,14 @@ MarkLocalBufferDirty(Buffer buffer)
 
 	bufHdr = GetLocalBufferDescriptor(bufid);
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	if (!(buf_state & BM_DIRTY))
 		pgBufferUsage.local_blks_dirtied++;
 
 	buf_state |= BM_DIRTY;
 
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -522,7 +522,7 @@ MarkLocalBufferDirty(Buffer buffer)
 bool
 StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * With AIO the buffer could have IO in progress, e.g. when there are two
@@ -542,7 +542,7 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 	/* Once we get here, there is definitely no I/O active on this buffer */
 
 	/* Check if someone else already did the I/O */
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 	if (forInput ? (buf_state & BM_VALID) : !(buf_state & BM_DIRTY))
 	{
 		return false;
@@ -559,11 +559,11 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
  * Like TerminateBufferIO, but for local buffers
  */
 void
-TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bits,
+TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint64 set_flag_bits,
 					   bool release_aio)
 {
 	/* Only need to adjust flags */
-	uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+	uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/* BM_IO_IN_PROGRESS isn't currently used for local buffers */
 
@@ -582,7 +582,7 @@ TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bit
 	}
 
 	buf_state |= set_flag_bits;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 	/* local buffers don't track IO using resowners */
 
@@ -606,7 +606,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 {
 	Buffer		buffer = BufferDescriptorGetBuffer(bufHdr);
 	int			bufid = -buffer - 1;
-	uint32		buf_state;
+	uint64		buf_state;
 	LocalBufferLookupEnt *hresult;
 
 	/*
@@ -622,7 +622,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 		Assert(!pgaio_wref_valid(&bufHdr->io_wref));
 	}
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/*
 	 * We need to test not just LocalRefCount[bufid] but also the BufferDesc
@@ -647,7 +647,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 	ClearBufferTag(&bufHdr->tag);
 	buf_state &= ~BUF_FLAG_MASK;
 	buf_state &= ~BUF_USAGECOUNT_MASK;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -671,9 +671,9 @@ DropRelationLocalBuffers(RelFileLocator rlocator, ForkNumber *forkNum,
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (!(buf_state & BM_TAG_VALID) ||
 			!BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -706,9 +706,9 @@ DropRelationAllLocalBuffers(RelFileLocator rlocator)
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if ((buf_state & BM_TAG_VALID) &&
 			BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -804,11 +804,11 @@ InitLocalBuffers(void)
 bool
 PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	Buffer		buffer = BufferDescriptorGetBuffer(buf_hdr);
 	int			bufid = -buffer - 1;
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	if (LocalRefCount[bufid] == 0)
 	{
@@ -819,7 +819,7 @@ PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 		{
 			buf_state += BUF_USAGECOUNT_ONE;
 		}
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/*
 		 * See comment in PinBuffer().
@@ -856,14 +856,14 @@ UnpinLocalBufferNoOwner(Buffer buffer)
 	if (--LocalRefCount[buffid] == 0)
 	{
 		BufferDesc *buf_hdr = GetLocalBufferDescriptor(buffid);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		NLocalPinnedBuffers--;
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state -= BUF_REFCOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/* see comment in UnpinBufferNoOwner */
 		VALGRIND_MAKE_MEM_NOACCESS(LocalBufHdrGetBlock(buf_hdr), BLCKSZ);
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index c29b784dfa1..32bd8aa784a 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -192,7 +192,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 		for (i = 0; i < NBuffers; i++)
 		{
 			BufferDesc *bufHdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			CHECK_FOR_INTERRUPTS();
 
@@ -559,7 +559,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		CHECK_FOR_INTERRUPTS();
 
@@ -570,7 +570,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 		 * noticeably increase the cost of the function.
 		 */
 		bufHdr = GetBufferDescriptor(i);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (buf_state & BM_VALID)
 		{
@@ -620,7 +620,7 @@ pg_buffercache_usage_counts(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		int			usage_count;
 
 		CHECK_FOR_INTERRUPTS();
diff --git a/src/test/modules/test_aio/test_aio.c b/src/test/modules/test_aio/test_aio.c
index d7eadeab256..488d98e7e66 100644
--- a/src/test/modules/test_aio/test_aio.c
+++ b/src/test/modules/test_aio/test_aio.c
@@ -308,9 +308,9 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 {
 	Buffer		buf;
 	BufferDesc *buf_hdr;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		was_pinned = false;
-	uint32		unset_bits = 0;
+	uint64		unset_bits = 0;
 
 	/* place buffer in shared buffers without erroring out */
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_ZERO_AND_LOCK, NULL);
@@ -319,7 +319,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	}
 	else
 	{
@@ -340,7 +340,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_state &= ~unset_bits;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 	else
 	{
@@ -489,7 +489,7 @@ invalidate_rel_block(PG_FUNCTION_ARGS)
 
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-			if (pg_atomic_read_u32(&buf_hdr->state) & BM_DIRTY)
+			if (pg_atomic_read_u64(&buf_hdr->state) & BM_DIRTY)
 			{
 				if (BufferIsLocal(buf))
 					FlushLocalBuffer(buf_hdr, NULL);
@@ -572,7 +572,7 @@ buffer_call_terminate_io(PG_FUNCTION_ARGS)
 	bool		io_error = PG_GETARG_BOOL(3);
 	bool		release_aio = PG_GETARG_BOOL(4);
 	bool		clear_dirty = false;
-	uint32		set_flag_bits = 0;
+	uint64		set_flag_bits = 0;
 
 	if (io_error)
 		set_flag_bits |= BM_IO_ERROR;
-- 
2.48.1.76.g4e746b1a31.dirty


--mhhc7c45w3dmihtp
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v6-0005-Rename-BUFFERPIN-wait-event-class-to-BUFFER.patch"



^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* [PATCH v7 11/15] bufmgr: Change BufferDesc.state to be a 64bit atomic
@ 2025-12-02 23:46  Andres Freund <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Andres Freund @ 2025-12-02 23:46 UTC (permalink / raw)

This is motivated by wanting to merge buffer content locks into
BufferDesc.state in a future commit, rather than having a separate lwlock (see
commit c75ebc657ff more details). As this change is rather mechanical, it
seems to make sense to split it out into a separate commit, for easier review.

Reviewed-by: Melanie Plageman <[email protected]>
Discussion: https://postgr.es/m/fvfmkr5kk4nyex56ejgxj3uzi63isfxovp2biecb4bspbjrze7@az2pljabhnff
---
 src/include/storage/buf_internals.h           |  88 +++++----
 src/include/storage/procnumber.h              |  14 +-
 src/backend/storage/buffer/buf_init.c         |   2 +-
 src/backend/storage/buffer/bufmgr.c           | 170 +++++++++---------
 src/backend/storage/buffer/freelist.c         |  24 +--
 src/backend/storage/buffer/localbuf.c         |  72 ++++----
 contrib/pg_buffercache/pg_buffercache_pages.c |   8 +-
 src/test/modules/test_aio/test_aio.c          |  12 +-
 8 files changed, 205 insertions(+), 185 deletions(-)

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index 5400c56a965..28519ad2813 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -30,7 +30,7 @@
 #include "utils/resowner.h"
 
 /*
- * Buffer state is a single 32-bit variable where following data is combined.
+ * Buffer state is a single 64-bit variable where following data is combined.
  *
  * - 18 bits refcount
  * - 4 bits usage count
@@ -39,6 +39,9 @@
  * Combining these values allows to perform some operations without locking
  * the buffer header, by modifying them together with a CAS loop.
  *
+ * NB: A future commit will use a significant portion of the remaining bits to
+ * implement buffer locking as part of the state variable.
+ *
  * The definition of buffer state components is below.
  */
 #define BUF_REFCOUNT_BITS 18
@@ -49,15 +52,21 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
 				 "parts of buffer state space need to equal 32");
 
 #define BUF_REFCOUNT_ONE 1
-#define BUF_REFCOUNT_MASK ((1U << BUF_REFCOUNT_BITS) - 1)
-#define BUF_USAGECOUNT_MASK (((1U << BUF_USAGECOUNT_BITS) - 1) << (BUF_REFCOUNT_BITS))
-#define BUF_USAGECOUNT_ONE (1U << BUF_REFCOUNT_BITS)
+#define BUF_REFCOUNT_MASK \
+	((UINT64CONST(1) << BUF_REFCOUNT_BITS) - 1)
+#define BUF_USAGECOUNT_MASK \
+	(((UINT64CONST(1) << BUF_USAGECOUNT_BITS) - 1) << (BUF_REFCOUNT_BITS))
+#define BUF_USAGECOUNT_ONE \
+	(UINT64CONST(1) << BUF_REFCOUNT_BITS)
 #define BUF_USAGECOUNT_SHIFT BUF_REFCOUNT_BITS
-#define BUF_FLAG_MASK (((1U << BUF_FLAG_BITS) - 1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS))
+#define BUF_FLAG_MASK \
+	(((UINT64CONST(1) << BUF_FLAG_BITS) - 1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS))
 
 /* Get refcount and usagecount from buffer state */
-#define BUF_STATE_GET_REFCOUNT(state) ((state) & BUF_REFCOUNT_MASK)
-#define BUF_STATE_GET_USAGECOUNT(state) (((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT)
+#define BUF_STATE_GET_REFCOUNT(state) \
+	((uint32)((state) & BUF_REFCOUNT_MASK))
+#define BUF_STATE_GET_USAGECOUNT(state) \
+	((uint32)(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT))
 
 /*
  * Flags for buffer descriptors
@@ -65,17 +74,28 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  * Note: BM_TAG_VALID essentially means that there is a buffer hashtable
  * entry associated with the buffer's tag.
  */
-#define BM_LOCKED				(1U << 22)	/* buffer header is locked */
-#define BM_DIRTY				(1U << 23)	/* data needs writing */
-#define BM_VALID				(1U << 24)	/* data is valid */
-#define BM_TAG_VALID			(1U << 25)	/* tag is assigned */
-#define BM_IO_IN_PROGRESS		(1U << 26)	/* read or write in progress */
-#define BM_IO_ERROR				(1U << 27)	/* previous I/O failed */
-#define BM_JUST_DIRTIED			(1U << 28)	/* dirtied since write started */
-#define BM_PIN_COUNT_WAITER		(1U << 29)	/* have waiter for sole pin */
-#define BM_CHECKPOINT_NEEDED	(1U << 30)	/* must write for checkpoint */
-#define BM_PERMANENT			(1U << 31)	/* permanent buffer (not unlogged,
-											 * or init fork) */
+
+/* buffer header is locked */
+#define BM_LOCKED				(UINT64CONST(1) << 22)
+/* data needs writing */
+#define BM_DIRTY				(UINT64CONST(1) << 23)
+/* data is valid */
+#define BM_VALID				(UINT64CONST(1) << 24)
+/* tag is assigned */
+#define BM_TAG_VALID			(UINT64CONST(1) << 25)
+/* read or write in progress */
+#define BM_IO_IN_PROGRESS		(UINT64CONST(1) << 26)
+/* previous I/O failed */
+#define BM_IO_ERROR				(UINT64CONST(1) << 27)
+/* dirtied since write started */
+#define BM_JUST_DIRTIED			(UINT64CONST(1) << 28)
+/* have waiter for sole pin */
+#define BM_PIN_COUNT_WAITER		(UINT64CONST(1) << 29)
+/* must write for checkpoint */
+#define BM_CHECKPOINT_NEEDED	(UINT64CONST(1) << 30)
+/* permanent buffer (not unlogged, or init fork) */
+#define BM_PERMANENT			(UINT64CONST(1) << 31)
+
 /*
  * The maximum allowed value of usage_count represents a tradeoff between
  * accuracy and speed of the clock-sweep buffer management algorithm.  A
@@ -86,7 +106,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 #define BM_MAX_USAGE_COUNT	5
 
-StaticAssertDecl(BM_MAX_USAGE_COUNT < (1 << BUF_USAGECOUNT_BITS),
+StaticAssertDecl(BM_MAX_USAGE_COUNT < (UINT64CONST(1) << BUF_USAGECOUNT_BITS),
 				 "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
 StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
 				 "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
@@ -251,8 +271,8 @@ BufMappingPartitionLockByIndex(uint32 index)
  * We use this same struct for local buffer headers, but the locks are not
  * used and not all of the flag bits are useful either. To avoid unnecessary
  * overhead, manipulations of the state field should be done without actual
- * atomic operations (i.e. only pg_atomic_read_u32() and
- * pg_atomic_unlocked_write_u32()).
+ * atomic operations (i.e. only pg_atomic_read_u64() and
+ * pg_atomic_unlocked_write_u64()).
  *
  * Be careful to avoid increasing the size of the struct when adding or
  * reordering members.  Keeping it below 64 bytes (the most common CPU
@@ -280,7 +300,7 @@ typedef struct BufferDesc
 	 * State of the buffer, containing flags, refcount and usagecount. See
 	 * BUF_* and BM_* defines at the top of this file.
 	 */
-	pg_atomic_uint32 state;
+	pg_atomic_uint64 state;
 
 	/*
 	 * Backend of pin-count waiter. The buffer header spinlock needs to be
@@ -386,7 +406,7 @@ BufferDescriptorGetContentLock(const BufferDesc *bdesc)
  * Functions for acquiring/releasing a shared buffer header's spinlock.  Do
  * not apply these to local buffers!
  */
-extern uint32 LockBufHdr(BufferDesc *desc);
+extern uint64 LockBufHdr(BufferDesc *desc);
 
 /*
  * Unlock the buffer header.
@@ -397,9 +417,9 @@ extern uint32 LockBufHdr(BufferDesc *desc);
 static inline void
 UnlockBufHdr(BufferDesc *desc)
 {
-	Assert(pg_atomic_read_u32(&desc->state) & BM_LOCKED);
+	Assert(pg_atomic_read_u64(&desc->state) & BM_LOCKED);
 
-	pg_atomic_fetch_sub_u32(&desc->state, BM_LOCKED);
+	pg_atomic_fetch_sub_u64(&desc->state, BM_LOCKED);
 }
 
 /*
@@ -410,14 +430,14 @@ UnlockBufHdr(BufferDesc *desc)
  * Note that this approach would not work for usagecount, since we need to cap
  * the usagecount at BM_MAX_USAGE_COUNT.
  */
-static inline uint32
-UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
-				uint32 set_bits, uint32 unset_bits,
+static inline uint64
+UnlockBufHdrExt(BufferDesc *desc, uint64 old_buf_state,
+				uint64 set_bits, uint64 unset_bits,
 				int refcount_change)
 {
 	for (;;)
 	{
-		uint32		buf_state = old_buf_state;
+		uint64		buf_state = old_buf_state;
 
 		Assert(buf_state & BM_LOCKED);
 
@@ -428,7 +448,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 		if (refcount_change != 0)
 			buf_state += BUF_REFCOUNT_ONE * refcount_change;
 
-		if (pg_atomic_compare_exchange_u32(&desc->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&desc->state, &old_buf_state,
 										   buf_state))
 		{
 			return old_buf_state;
@@ -436,7 +456,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 	}
 }
 
-extern uint32 WaitBufHdrUnlocked(BufferDesc *buf);
+extern uint64 WaitBufHdrUnlocked(BufferDesc *buf);
 
 /* in bufmgr.c */
 
@@ -496,14 +516,14 @@ extern void TrackNewBufferPin(Buffer buf);
 
 /* solely to make it easier to write tests */
 extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
-extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 							  bool forget_owner, bool release_aio);
 
 
 /* freelist.c */
 extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
 extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
-									 uint32 *buf_state, bool *from_ring);
+									 uint64 *buf_state, bool *from_ring);
 extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
 								 BufferDesc *buf, bool from_ring);
 
@@ -539,7 +559,7 @@ extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
 										  uint32 *extended_by);
 extern void MarkLocalBufferDirty(Buffer buffer);
 extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
-								   uint32 set_flag_bits, bool release_aio);
+								   uint64 set_flag_bits, bool release_aio);
 extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
 extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
 extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
diff --git a/src/include/storage/procnumber.h b/src/include/storage/procnumber.h
index 2ddaaf0c646..6baac7c77f1 100644
--- a/src/include/storage/procnumber.h
+++ b/src/include/storage/procnumber.h
@@ -27,13 +27,13 @@ typedef int ProcNumber;
 
 /*
  * Note: MAX_BACKENDS_BITS is 18 as that is the space available for buffer
- * refcounts in buf_internals.h.  This limitation could be lifted by using a
- * 64bit state; but it's unlikely to be worthwhile as 2^18-1 backends exceed
- * currently realistic configurations. Even if that limitation were removed,
- * we still could not a) exceed 2^23-1 because inval.c stores the ProcNumber
- * as a 3-byte signed integer, b) INT_MAX/4 because some places compute
- * 4*MaxBackends without any overflow check.  We check that the configured
- * number of backends does not exceed MAX_BACKENDS in InitializeMaxBackends().
+ * refcounts in buf_internals.h.  This limitation could be lifted, but it's
+ * unlikely to be worthwhile as 2^18-1 backends exceed currently realistic
+ * configurations. Even if that limitation were removed, we still could not a)
+ * exceed 2^23-1 because inval.c stores the ProcNumber as a 3-byte signed
+ * integer, b) INT_MAX/4 because some places compute 4*MaxBackends without any
+ * overflow check.  We check that the configured number of backends does not
+ * exceed MAX_BACKENDS in InitializeMaxBackends().
  */
 #define MAX_BACKENDS_BITS		18
 #define MAX_BACKENDS			((1U << MAX_BACKENDS_BITS)-1)
diff --git a/src/backend/storage/buffer/buf_init.c b/src/backend/storage/buffer/buf_init.c
index 6fd3a6bbac5..25f71191ec3 100644
--- a/src/backend/storage/buffer/buf_init.c
+++ b/src/backend/storage/buffer/buf_init.c
@@ -121,7 +121,7 @@ BufferManagerShmemInit(void)
 
 			ClearBufferTag(&buf->tag);
 
-			pg_atomic_init_u32(&buf->state, 0);
+			pg_atomic_init_u64(&buf->state, 0);
 			buf->wait_backend_pgprocno = INVALID_PROC_NUMBER;
 
 			buf->buf_id = i;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index be32bd596f6..d0b8f8d20eb 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -775,7 +775,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 {
 	BufferDesc *bufHdr;
 	BufferTag	tag;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(recent_buffer));
 
@@ -788,7 +788,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 		int			b = -recent_buffer - 1;
 
 		bufHdr = GetLocalBufferDescriptor(b);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		/* Is it still valid and holding the right tag? */
 		if ((buf_state & BM_VALID) && BufferTagsEqual(&tag, &bufHdr->tag))
@@ -1381,8 +1381,8 @@ StartReadBuffersImpl(ReadBuffersOperation *operation,
 				bufHdr = GetLocalBufferDescriptor(-buffers[i] - 1);
 			else
 				bufHdr = GetBufferDescriptor(buffers[i] - 1);
-			Assert(pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID);
-			found = pg_atomic_read_u32(&bufHdr->state) & BM_VALID;
+			Assert(pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID);
+			found = pg_atomic_read_u64(&bufHdr->state) & BM_VALID;
 		}
 		else
 		{
@@ -1608,10 +1608,10 @@ CheckReadBuffersOperation(ReadBuffersOperation *operation, bool is_complete)
 			GetBufferDescriptor(buffer - 1);
 
 		Assert(BufferGetBlockNumber(buffer) == operation->blocknum + i);
-		Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_TAG_VALID);
+		Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_TAG_VALID);
 
 		if (i < operation->nblocks_done)
-			Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_VALID);
+			Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_VALID);
 	}
 #endif
 }
@@ -2078,8 +2078,8 @@ BufferAlloc(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 	int			existing_buf_id;
 	Buffer		victim_buffer;
 	BufferDesc *victim_buf_hdr;
-	uint32		victim_buf_state;
-	uint32		set_bits = 0;
+	uint64		victim_buf_state;
+	uint64		set_bits = 0;
 
 	/* Make sure we will have room to remember the buffer pin */
 	ResourceOwnerEnlarge(CurrentResourceOwner);
@@ -2246,7 +2246,7 @@ InvalidateBuffer(BufferDesc *buf)
 	uint32		oldHash;		/* hash value for oldTag */
 	LWLock	   *oldPartitionLock;	/* buffer partition lock for it */
 	uint32		oldFlags;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/* Save the original buffer tag before dropping the spinlock */
 	oldTag = buf->tag;
@@ -2337,7 +2337,7 @@ retry:
 static bool
 InvalidateVictimBuffer(BufferDesc *buf_hdr)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	uint32		hash;
 	LWLock	   *partition_lock;
 	BufferTag	tag;
@@ -2397,10 +2397,10 @@ InvalidateVictimBuffer(BufferDesc *buf_hdr)
 
 	LWLockRelease(partition_lock);
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	Assert(!(buf_state & (BM_DIRTY | BM_VALID | BM_TAG_VALID)));
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
-	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u32(&buf_hdr->state)) > 0);
+	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u64(&buf_hdr->state)) > 0);
 
 	return true;
 }
@@ -2410,7 +2410,7 @@ GetVictimBuffer(BufferAccessStrategy strategy, IOContext io_context)
 {
 	BufferDesc *buf_hdr;
 	Buffer		buf;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		from_ring;
 
 	/*
@@ -2543,7 +2543,7 @@ again:
 
 	/* a final set of sanity checks */
 #ifdef USE_ASSERT_CHECKING
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) == 1);
 	Assert(!(buf_state & (BM_TAG_VALID | BM_VALID | BM_DIRTY)));
@@ -2834,13 +2834,13 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
 			 */
 			do
 			{
-				pg_atomic_fetch_and_u32(&existing_hdr->state, ~BM_VALID);
+				pg_atomic_fetch_and_u64(&existing_hdr->state, ~BM_VALID);
 			} while (!StartBufferIO(existing_hdr, true, false));
 		}
 		else
 		{
-			uint32		buf_state;
-			uint32		set_bits = 0;
+			uint64		buf_state;
+			uint64		set_bits = 0;
 
 			buf_state = LockBufHdr(victim_buf_hdr);
 
@@ -3016,7 +3016,7 @@ BufferIsDirty(Buffer buffer)
 		Assert(BufferIsLockedByMeInMode(buffer, BUFFER_LOCK_EXCLUSIVE));
 	}
 
-	return pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY;
+	return pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY;
 }
 
 /*
@@ -3032,8 +3032,8 @@ void
 MarkBufferDirty(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
-	uint32		old_buf_state;
+	uint64		buf_state;
+	uint64		old_buf_state;
 
 	if (!BufferIsValid(buffer))
 		elog(ERROR, "bad buffer ID: %d", buffer);
@@ -3053,7 +3053,7 @@ MarkBufferDirty(Buffer buffer)
 	 * NB: We have to wait for the buffer header spinlock to be not held, as
 	 * TerminateBufferIO() relies on the spinlock.
 	 */
-	old_buf_state = pg_atomic_read_u32(&bufHdr->state);
+	old_buf_state = pg_atomic_read_u64(&bufHdr->state);
 	for (;;)
 	{
 		if (old_buf_state & BM_LOCKED)
@@ -3064,7 +3064,7 @@ MarkBufferDirty(Buffer buffer)
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state |= BM_DIRTY | BM_JUST_DIRTIED;
 
-		if (pg_atomic_compare_exchange_u32(&bufHdr->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&bufHdr->state, &old_buf_state,
 										   buf_state))
 			break;
 	}
@@ -3168,10 +3168,10 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 
 	if (ref == NULL)
 	{
-		uint32		buf_state;
-		uint32		old_buf_state;
+		uint64		buf_state;
+		uint64		old_buf_state;
 
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			if (unlikely(skip_if_not_valid && !(old_buf_state & BM_VALID)))
@@ -3205,7 +3205,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 					buf_state += BUF_USAGECOUNT_ONE;
 			}
 
-			if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+			if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 											   buf_state))
 			{
 				result = (buf_state & BM_VALID) != 0;
@@ -3232,7 +3232,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 		 * that the buffer page is legitimately non-accessible here.  We
 		 * cannot meddle with that.
 		 */
-		result = (pg_atomic_read_u32(&buf->state) & BM_VALID) != 0;
+		result = (pg_atomic_read_u64(&buf->state) & BM_VALID) != 0;
 
 		Assert(ref->data.refcount > 0);
 		ref->data.refcount++;
@@ -3267,7 +3267,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 static void
 PinBuffer_Locked(BufferDesc *buf)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	/*
 	 * As explained, We don't expect any preexisting pins. That allows us to
@@ -3279,7 +3279,7 @@ PinBuffer_Locked(BufferDesc *buf)
 	 * Since we hold the buffer spinlock, we can update the buffer state and
 	 * release the lock in one operation.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 
 	UnlockBufHdrExt(buf, old_buf_state,
 					0, 0, 1);
@@ -3309,7 +3309,7 @@ WakePinCountWaiter(BufferDesc *buf)
 	 * BM_PIN_COUNT_WAITER if it stops waiting for a reason other than this
 	 * backend waking it up.
 	 */
-	uint32		buf_state = LockBufHdr(buf);
+	uint64		buf_state = LockBufHdr(buf);
 
 	if ((buf_state & BM_PIN_COUNT_WAITER) &&
 		BUF_STATE_GET_REFCOUNT(buf_state) == 1)
@@ -3356,7 +3356,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 	ref->data.refcount--;
 	if (ref->data.refcount == 0)
 	{
-		uint32		old_buf_state;
+		uint64		old_buf_state;
 
 		/*
 		 * Mark buffer non-accessible to Valgrind.
@@ -3374,7 +3374,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 		Assert(!LWLockHeldByMe(BufferDescriptorGetContentLock(buf)));
 
 		/* decrement the shared reference count */
-		old_buf_state = pg_atomic_fetch_sub_u32(&buf->state, BUF_REFCOUNT_ONE);
+		old_buf_state = pg_atomic_fetch_sub_u64(&buf->state, BUF_REFCOUNT_ONE);
 
 		/* Support LockBufferForCleanup() */
 		if (old_buf_state & BM_PIN_COUNT_WAITER)
@@ -3431,7 +3431,7 @@ TrackNewBufferPin(Buffer buf)
 static void
 BufferSync(int flags)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	int			buf_id;
 	int			num_to_scan;
 	int			num_spaces;
@@ -3441,7 +3441,7 @@ BufferSync(int flags)
 	Oid			last_tsid;
 	binaryheap *ts_heap;
 	int			i;
-	uint32		mask = BM_DIRTY;
+	uint64		mask = BM_DIRTY;
 	WritebackContext wb_context;
 
 	/*
@@ -3473,7 +3473,7 @@ BufferSync(int flags)
 	for (buf_id = 0; buf_id < NBuffers; buf_id++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
-		uint32		set_bits = 0;
+		uint64		set_bits = 0;
 
 		/*
 		 * Header spinlock is enough to examine BM_DIRTY, see comment in
@@ -3640,7 +3640,7 @@ BufferSync(int flags)
 		 * write the buffer though we didn't need to.  It doesn't seem worth
 		 * guarding against this, though.
 		 */
-		if (pg_atomic_read_u32(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
+		if (pg_atomic_read_u64(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
 		{
 			if (SyncOneBuffer(buf_id, false, &wb_context) & BUF_WRITTEN)
 			{
@@ -4010,7 +4010,7 @@ SyncOneBuffer(int buf_id, bool skip_recently_used, WritebackContext *wb_context)
 {
 	BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
 	int			result = 0;
-	uint32		buf_state;
+	uint64		buf_state;
 	BufferTag	tag;
 
 	/* Make sure we can handle the pin */
@@ -4259,7 +4259,7 @@ DebugPrintBufferRefcount(Buffer buffer)
 	int32		loccount;
 	char	   *result;
 	ProcNumber	backend;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
@@ -4276,9 +4276,9 @@ DebugPrintBufferRefcount(Buffer buffer)
 	}
 
 	/* theoretically we should lock the bufhdr here */
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
-	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
+	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%" PRIx64 ", refcount=%u %d)",
 					  buffer,
 					  relpathbackend(BufTagGetRelFileLocator(&buf->tag), backend,
 									 BufTagGetForkNum(&buf->tag)).str,
@@ -4378,7 +4378,7 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
 	instr_time	io_start;
 	Block		bufBlock;
 	char	   *bufToWrite;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * Try to start an I/O operation.  If StartBufferIO returns false, then
@@ -4576,7 +4576,7 @@ BufferIsPermanent(Buffer buffer)
 	 * not random garbage.
 	 */
 	bufHdr = GetBufferDescriptor(buffer - 1);
-	return (pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT) != 0;
+	return (pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT) != 0;
 }
 
 /*
@@ -5039,11 +5039,11 @@ FlushRelationBuffers(Relation rel)
 	{
 		for (i = 0; i < NLocBuffer; i++)
 		{
-			uint32		buf_state;
+			uint64		buf_state;
 
 			bufHdr = GetLocalBufferDescriptor(i);
 			if (BufTagMatchesRelFileLocator(&bufHdr->tag, &rel->rd_locator) &&
-				((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
+				((buf_state = pg_atomic_read_u64(&bufHdr->state)) &
 				 (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
 			{
 				ErrorContextCallback errcallback;
@@ -5079,7 +5079,7 @@ FlushRelationBuffers(Relation rel)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5151,7 +5151,7 @@ FlushRelationsAllBuffers(SMgrRelation *smgrs, int nrels)
 	{
 		SMgrSortArray *srelent = NULL;
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * As in DropRelationBuffers, an unlocked precheck should be safe and
@@ -5400,7 +5400,7 @@ FlushDatabaseBuffers(Oid dbid)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5548,13 +5548,13 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 	 * is only intended to be used in cases where failing to write out the
 	 * data would be harmless anyway, it doesn't really matter.
 	 */
-	if ((pg_atomic_read_u32(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
+	if ((pg_atomic_read_u64(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
 		(BM_DIRTY | BM_JUST_DIRTIED))
 	{
 		XLogRecPtr	lsn = InvalidXLogRecPtr;
 		bool		dirtied = false;
 		bool		delayChkptFlags = false;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * If we need to protect hint bit updates from torn writes, WAL-log a
@@ -5566,7 +5566,7 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 		 * when we call XLogInsert() since the value changes dynamically.
 		 */
 		if (XLogHintBitIsNeeded() &&
-			(pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT))
+			(pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT))
 		{
 			/*
 			 * If we must not write WAL, due to a relfilelocator-specific
@@ -5666,8 +5666,8 @@ UnlockBuffers(void)
 
 	if (buf)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		buf_state = LockBufHdr(buf);
 
@@ -5798,8 +5798,8 @@ LockBufferForCleanup(Buffer buffer)
 
 	for (;;)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -5947,7 +5947,7 @@ bool
 ConditionalLockBufferForCleanup(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state,
+	uint64		buf_state,
 				refcount;
 
 	Assert(BufferIsValid(buffer));
@@ -6005,7 +6005,7 @@ bool
 IsBufferCleanupOK(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 
@@ -6061,7 +6061,7 @@ WaitIO(BufferDesc *buf)
 	ConditionVariablePrepareToSleep(cv);
 	for (;;)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 		PgAioWaitRef iow;
 
 		/*
@@ -6135,7 +6135,7 @@ WaitIO(BufferDesc *buf)
 bool
 StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	ResourceOwnerEnlarge(CurrentResourceOwner);
 
@@ -6191,11 +6191,11 @@ StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
  * is being released)
  */
 void
-TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 				  bool forget_owner, bool release_aio)
 {
-	uint32		buf_state;
-	uint32		unset_flag_bits = 0;
+	uint64		buf_state;
+	uint64		unset_flag_bits = 0;
 	int			refcount_change = 0;
 
 	buf_state = LockBufHdr(buf);
@@ -6256,7 +6256,7 @@ static void
 AbortBufferIO(Buffer buffer)
 {
 	BufferDesc *buf_hdr = GetBufferDescriptor(buffer - 1);
-	uint32		buf_state;
+	uint64		buf_state;
 
 	buf_state = LockBufHdr(buf_hdr);
 	Assert(buf_state & (BM_IO_IN_PROGRESS | BM_TAG_VALID));
@@ -6350,10 +6350,10 @@ rlocator_comparator(const void *p1, const void *p2)
 /*
  * Lock buffer header - set BM_LOCKED in buffer state.
  */
-uint32
+uint64
 LockBufHdr(BufferDesc *desc)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	Assert(!BufferIsLocal(BufferDescriptorGetBuffer(desc)));
 
@@ -6362,7 +6362,7 @@ LockBufHdr(BufferDesc *desc)
 	 * infrastructure. The work necessary for that shows up in profiles and is
 	 * rarely necessary.
 	 */
-	old_buf_state = pg_atomic_fetch_or_u32(&desc->state, BM_LOCKED);
+	old_buf_state = pg_atomic_fetch_or_u64(&desc->state, BM_LOCKED);
 
 	if (unlikely(old_buf_state & BM_LOCKED))
 	{
@@ -6373,7 +6373,7 @@ LockBufHdr(BufferDesc *desc)
 		while (true)
 		{
 			/* set BM_LOCKED flag */
-			old_buf_state = pg_atomic_fetch_or_u32(&desc->state, BM_LOCKED);
+			old_buf_state = pg_atomic_fetch_or_u64(&desc->state, BM_LOCKED);
 			/* if it wasn't set before we're OK */
 			if (!(old_buf_state & BM_LOCKED))
 				break;
@@ -6392,20 +6392,20 @@ LockBufHdr(BufferDesc *desc)
  * Obviously the buffer could be locked by the time the value is returned, so
  * this is primarily useful in CAS style loops.
  */
-pg_noinline uint32
+pg_noinline uint64
 WaitBufHdrUnlocked(BufferDesc *buf)
 {
 	SpinDelayStatus delayStatus;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	init_local_spin_delay(&delayStatus);
 
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
 	while (buf_state & BM_LOCKED)
 	{
 		perform_spin_delay(&delayStatus);
-		buf_state = pg_atomic_read_u32(&buf->state);
+		buf_state = pg_atomic_read_u64(&buf->state);
 	}
 
 	finish_spin_delay(&delayStatus);
@@ -6693,12 +6693,12 @@ ResOwnerPrintBufferPin(Datum res)
 static bool
 EvictUnpinnedBufferInternal(BufferDesc *desc, bool *buffer_flushed)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result;
 
 	*buffer_flushed = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -6792,12 +6792,12 @@ EvictAllUnpinnedBuffers(int32 *buffers_evicted, int32 *buffers_flushed,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -6844,7 +6844,7 @@ EvictRelUnpinnedBuffers(Relation rel, int32 *buffers_evicted,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
@@ -6886,12 +6886,12 @@ static bool
 MarkDirtyUnpinnedBufferInternal(Buffer buf, BufferDesc *desc,
 								bool *buffer_already_dirty)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result = false;
 
 	*buffer_already_dirty = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -6989,7 +6989,7 @@ MarkDirtyRelUnpinnedBuffers(Relation rel,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
@@ -7043,12 +7043,12 @@ MarkDirtyAllUnpinnedBuffers(int32 *buffers_dirtied,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -7099,7 +7099,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		BufferDesc *buf_hdr = is_temp ?
 			GetLocalBufferDescriptor(-buffer - 1)
 			: GetBufferDescriptor(buffer - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * Check that all the buffers are actually ones that could conceivably
@@ -7117,7 +7117,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		}
 
 		if (is_temp)
-			buf_state = pg_atomic_read_u32(&buf_hdr->state);
+			buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		else
 			buf_state = LockBufHdr(buf_hdr);
 
@@ -7155,7 +7155,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		if (is_temp)
 		{
 			buf_state += BUF_REFCOUNT_ONE;
-			pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 		}
 		else
 			UnlockBufHdrExt(buf_hdr, buf_state, 0, 0, 1);
@@ -7341,13 +7341,13 @@ buffer_readv_complete_one(PgAioTargetData *td, uint8 buf_off, Buffer buffer,
 		: GetBufferDescriptor(buffer - 1);
 	BufferTag	tag = buf_hdr->tag;
 	char	   *bufdata = BufferGetBlock(buffer);
-	uint32		set_flag_bits;
+	uint64		set_flag_bits;
 	int			piv_flags;
 
 	/* check that the buffer is in the expected state for a read */
 #ifdef USE_ASSERT_CHECKING
 	{
-		uint32		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 		Assert(buf_state & BM_TAG_VALID);
 		Assert(!(buf_state & BM_VALID));
diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 28d952b3534..1d4f19a9afd 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -86,7 +86,7 @@ typedef struct BufferAccessStrategyData
 
 /* Prototypes for internal functions */
 static BufferDesc *GetBufferFromRing(BufferAccessStrategy strategy,
-									 uint32 *buf_state);
+									 uint64 *buf_state);
 static void AddBufferToRing(BufferAccessStrategy strategy,
 							BufferDesc *buf);
 
@@ -171,7 +171,7 @@ ClockSweepTick(void)
  *	before returning.
  */
 BufferDesc *
-StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_ring)
+StrategyGetBuffer(BufferAccessStrategy strategy, uint64 *buf_state, bool *from_ring)
 {
 	BufferDesc *buf;
 	int			bgwprocno;
@@ -230,8 +230,8 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 	trycounter = NBuffers;
 	for (;;)
 	{
-		uint32		old_buf_state;
-		uint32		local_buf_state;
+		uint64		old_buf_state;
+		uint64		local_buf_state;
 
 		buf = GetBufferDescriptor(ClockSweepTick());
 
@@ -239,7 +239,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 		 * Check whether the buffer can be used and pin it if so. Do this
 		 * using a CAS loop, to avoid having to lock the buffer header.
 		 */
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			local_buf_state = old_buf_state;
@@ -277,7 +277,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 			{
 				local_buf_state -= BUF_USAGECOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					trycounter = NBuffers;
@@ -289,7 +289,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 				/* pin the buffer if the CAS succeeds */
 				local_buf_state += BUF_REFCOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					/* Found a usable buffer */
@@ -655,12 +655,12 @@ FreeAccessStrategy(BufferAccessStrategy strategy)
  * returning.
  */
 static BufferDesc *
-GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
+GetBufferFromRing(BufferAccessStrategy strategy, uint64 *buf_state)
 {
 	BufferDesc *buf;
 	Buffer		bufnum;
-	uint32		old_buf_state;
-	uint32		local_buf_state;	/* to avoid repeated (de-)referencing */
+	uint64		old_buf_state;
+	uint64		local_buf_state;	/* to avoid repeated (de-)referencing */
 
 
 	/* Advance to next ring slot */
@@ -682,7 +682,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 	 * Check whether the buffer can be used and pin it if so. Do this using a
 	 * CAS loop, to avoid having to lock the buffer header.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 	for (;;)
 	{
 		local_buf_state = old_buf_state;
@@ -710,7 +710,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 		/* pin the buffer if the CAS succeeds */
 		local_buf_state += BUF_REFCOUNT_ONE;
 
-		if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 										   local_buf_state))
 		{
 			*buf_state = local_buf_state;
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 15aac7d1c9f..a41a5facd3a 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -148,7 +148,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	}
 	else
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		victim_buffer = GetLocalVictimBuffer();
 		bufid = -victim_buffer - 1;
@@ -165,10 +165,10 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		 */
 		bufHdr->tag = newTag;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		buf_state &= ~(BUF_FLAG_MASK | BUF_USAGECOUNT_MASK);
 		buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 		*foundPtr = false;
 	}
@@ -245,12 +245,12 @@ GetLocalVictimBuffer(void)
 
 		if (LocalRefCount[victim_bufid] == 0)
 		{
-			uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 			if (BUF_STATE_GET_USAGECOUNT(buf_state) > 0)
 			{
 				buf_state -= BUF_USAGECOUNT_ONE;
-				pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+				pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 				trycounter = NLocBuffer;
 			}
 			else if (BUF_STATE_GET_REFCOUNT(buf_state) > 0)
@@ -286,13 +286,13 @@ GetLocalVictimBuffer(void)
 	 * this buffer is not referenced but it might still be dirty. if that's
 	 * the case, write it out before reusing it!
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY)
 		FlushLocalBuffer(bufHdr, NULL);
 
 	/*
 	 * Remove the victim buffer from the hashtable and mark as invalid.
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID)
 	{
 		InvalidateLocalBuffer(bufHdr, false);
 
@@ -417,7 +417,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 		if (found)
 		{
 			BufferDesc *existing_hdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			UnpinLocalBuffer(BufferDescriptorGetBuffer(victim_buf_hdr));
 
@@ -428,18 +428,18 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 			/*
 			 * Clear the BM_VALID bit, do StartLocalBufferIO() and proceed.
 			 */
-			buf_state = pg_atomic_read_u32(&existing_hdr->state);
+			buf_state = pg_atomic_read_u64(&existing_hdr->state);
 			Assert(buf_state & BM_TAG_VALID);
 			Assert(!(buf_state & BM_DIRTY));
 			buf_state &= ~BM_VALID;
-			pg_atomic_unlocked_write_u32(&existing_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&existing_hdr->state, buf_state);
 
 			/* no need to loop for local buffers */
 			StartLocalBufferIO(existing_hdr, true, false);
 		}
 		else
 		{
-			uint32		buf_state = pg_atomic_read_u32(&victim_buf_hdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&victim_buf_hdr->state);
 
 			Assert(!(buf_state & (BM_VALID | BM_TAG_VALID | BM_DIRTY | BM_JUST_DIRTIED)));
 
@@ -447,7 +447,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 
 			buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
 
-			pg_atomic_unlocked_write_u32(&victim_buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&victim_buf_hdr->state, buf_state);
 
 			hresult->id = victim_buf_id;
 
@@ -467,13 +467,13 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 	{
 		Buffer		buf = buffers[i];
 		BufferDesc *buf_hdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		buf_state |= BM_VALID;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 
 	*extended_by = extend_by;
@@ -492,7 +492,7 @@ MarkLocalBufferDirty(Buffer buffer)
 {
 	int			bufid;
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsLocal(buffer));
 
@@ -506,14 +506,14 @@ MarkLocalBufferDirty(Buffer buffer)
 
 	bufHdr = GetLocalBufferDescriptor(bufid);
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	if (!(buf_state & BM_DIRTY))
 		pgBufferUsage.local_blks_dirtied++;
 
 	buf_state |= BM_DIRTY;
 
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -522,7 +522,7 @@ MarkLocalBufferDirty(Buffer buffer)
 bool
 StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * With AIO the buffer could have IO in progress, e.g. when there are two
@@ -542,7 +542,7 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 	/* Once we get here, there is definitely no I/O active on this buffer */
 
 	/* Check if someone else already did the I/O */
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 	if (forInput ? (buf_state & BM_VALID) : !(buf_state & BM_DIRTY))
 	{
 		return false;
@@ -559,11 +559,11 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
  * Like TerminateBufferIO, but for local buffers
  */
 void
-TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bits,
+TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint64 set_flag_bits,
 					   bool release_aio)
 {
 	/* Only need to adjust flags */
-	uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+	uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/* BM_IO_IN_PROGRESS isn't currently used for local buffers */
 
@@ -582,7 +582,7 @@ TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bit
 	}
 
 	buf_state |= set_flag_bits;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 	/* local buffers don't track IO using resowners */
 
@@ -606,7 +606,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 {
 	Buffer		buffer = BufferDescriptorGetBuffer(bufHdr);
 	int			bufid = -buffer - 1;
-	uint32		buf_state;
+	uint64		buf_state;
 	LocalBufferLookupEnt *hresult;
 
 	/*
@@ -622,7 +622,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 		Assert(!pgaio_wref_valid(&bufHdr->io_wref));
 	}
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/*
 	 * We need to test not just LocalRefCount[bufid] but also the BufferDesc
@@ -647,7 +647,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 	ClearBufferTag(&bufHdr->tag);
 	buf_state &= ~BUF_FLAG_MASK;
 	buf_state &= ~BUF_USAGECOUNT_MASK;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -671,9 +671,9 @@ DropRelationLocalBuffers(RelFileLocator rlocator, ForkNumber *forkNum,
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (!(buf_state & BM_TAG_VALID) ||
 			!BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -706,9 +706,9 @@ DropRelationAllLocalBuffers(RelFileLocator rlocator)
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if ((buf_state & BM_TAG_VALID) &&
 			BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -804,11 +804,11 @@ InitLocalBuffers(void)
 bool
 PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	Buffer		buffer = BufferDescriptorGetBuffer(buf_hdr);
 	int			bufid = -buffer - 1;
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	if (LocalRefCount[bufid] == 0)
 	{
@@ -819,7 +819,7 @@ PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 		{
 			buf_state += BUF_USAGECOUNT_ONE;
 		}
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/*
 		 * See comment in PinBuffer().
@@ -856,14 +856,14 @@ UnpinLocalBufferNoOwner(Buffer buffer)
 	if (--LocalRefCount[buffid] == 0)
 	{
 		BufferDesc *buf_hdr = GetLocalBufferDescriptor(buffid);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		NLocalPinnedBuffers--;
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state -= BUF_REFCOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/* see comment in UnpinBufferNoOwner */
 		VALGRIND_MAKE_MEM_NOACCESS(LocalBufHdrGetBlock(buf_hdr), BLCKSZ);
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index 702307a49e2..294caf7a1eb 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -199,7 +199,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 		for (i = 0; i < NBuffers; i++)
 		{
 			BufferDesc *bufHdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			CHECK_FOR_INTERRUPTS();
 
@@ -615,7 +615,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		CHECK_FOR_INTERRUPTS();
 
@@ -626,7 +626,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 		 * noticeably increase the cost of the function.
 		 */
 		bufHdr = GetBufferDescriptor(i);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (buf_state & BM_VALID)
 		{
@@ -676,7 +676,7 @@ pg_buffercache_usage_counts(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		int			usage_count;
 
 		CHECK_FOR_INTERRUPTS();
diff --git a/src/test/modules/test_aio/test_aio.c b/src/test/modules/test_aio/test_aio.c
index d7eadeab256..488d98e7e66 100644
--- a/src/test/modules/test_aio/test_aio.c
+++ b/src/test/modules/test_aio/test_aio.c
@@ -308,9 +308,9 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 {
 	Buffer		buf;
 	BufferDesc *buf_hdr;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		was_pinned = false;
-	uint32		unset_bits = 0;
+	uint64		unset_bits = 0;
 
 	/* place buffer in shared buffers without erroring out */
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_ZERO_AND_LOCK, NULL);
@@ -319,7 +319,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	}
 	else
 	{
@@ -340,7 +340,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_state &= ~unset_bits;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 	else
 	{
@@ -489,7 +489,7 @@ invalidate_rel_block(PG_FUNCTION_ARGS)
 
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-			if (pg_atomic_read_u32(&buf_hdr->state) & BM_DIRTY)
+			if (pg_atomic_read_u64(&buf_hdr->state) & BM_DIRTY)
 			{
 				if (BufferIsLocal(buf))
 					FlushLocalBuffer(buf_hdr, NULL);
@@ -572,7 +572,7 @@ buffer_call_terminate_io(PG_FUNCTION_ARGS)
 	bool		io_error = PG_GETARG_BOOL(3);
 	bool		release_aio = PG_GETARG_BOOL(4);
 	bool		clear_dirty = false;
-	uint32		set_flag_bits = 0;
+	uint64		set_flag_bits = 0;
 
 	if (io_error)
 		set_flag_bits |= BM_IO_ERROR;
-- 
2.48.1.76.g4e746b1a31.dirty


--kad4mm4awdo7v2ki
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v7-0012-bufmgr-Implement-buffer-content-locks-independent.patch"



^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* [PATCH v8 06/10] bufmgr: Change BufferDesc.state to be a 64bit atomic
@ 2025-12-18 23:28  Andres Freund <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Andres Freund @ 2025-12-18 23:28 UTC (permalink / raw)

This is motivated by wanting to merge buffer content locks into
BufferDesc.state in a future commit, rather than having a separate lwlock (see
commit c75ebc657ff more details). As this change is rather mechanical, it
seems to make sense to split it out into a separate commit, for easier review.

Reviewed-by: Melanie Plageman <[email protected]>
Discussion: https://postgr.es/m/fvfmkr5kk4nyex56ejgxj3uzi63isfxovp2biecb4bspbjrze7@az2pljabhnff
---
 src/include/storage/buf_internals.h           |  88 +++++----
 src/include/storage/procnumber.h              |  14 +-
 src/backend/storage/buffer/buf_init.c         |   2 +-
 src/backend/storage/buffer/bufmgr.c           | 170 +++++++++---------
 src/backend/storage/buffer/freelist.c         |  24 +--
 src/backend/storage/buffer/localbuf.c         |  72 ++++----
 contrib/pg_buffercache/pg_buffercache_pages.c |   8 +-
 src/test/modules/test_aio/test_aio.c          |  12 +-
 8 files changed, 205 insertions(+), 185 deletions(-)

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index 5400c56a965..28519ad2813 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -30,7 +30,7 @@
 #include "utils/resowner.h"
 
 /*
- * Buffer state is a single 32-bit variable where following data is combined.
+ * Buffer state is a single 64-bit variable where following data is combined.
  *
  * - 18 bits refcount
  * - 4 bits usage count
@@ -39,6 +39,9 @@
  * Combining these values allows to perform some operations without locking
  * the buffer header, by modifying them together with a CAS loop.
  *
+ * NB: A future commit will use a significant portion of the remaining bits to
+ * implement buffer locking as part of the state variable.
+ *
  * The definition of buffer state components is below.
  */
 #define BUF_REFCOUNT_BITS 18
@@ -49,15 +52,21 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
 				 "parts of buffer state space need to equal 32");
 
 #define BUF_REFCOUNT_ONE 1
-#define BUF_REFCOUNT_MASK ((1U << BUF_REFCOUNT_BITS) - 1)
-#define BUF_USAGECOUNT_MASK (((1U << BUF_USAGECOUNT_BITS) - 1) << (BUF_REFCOUNT_BITS))
-#define BUF_USAGECOUNT_ONE (1U << BUF_REFCOUNT_BITS)
+#define BUF_REFCOUNT_MASK \
+	((UINT64CONST(1) << BUF_REFCOUNT_BITS) - 1)
+#define BUF_USAGECOUNT_MASK \
+	(((UINT64CONST(1) << BUF_USAGECOUNT_BITS) - 1) << (BUF_REFCOUNT_BITS))
+#define BUF_USAGECOUNT_ONE \
+	(UINT64CONST(1) << BUF_REFCOUNT_BITS)
 #define BUF_USAGECOUNT_SHIFT BUF_REFCOUNT_BITS
-#define BUF_FLAG_MASK (((1U << BUF_FLAG_BITS) - 1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS))
+#define BUF_FLAG_MASK \
+	(((UINT64CONST(1) << BUF_FLAG_BITS) - 1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS))
 
 /* Get refcount and usagecount from buffer state */
-#define BUF_STATE_GET_REFCOUNT(state) ((state) & BUF_REFCOUNT_MASK)
-#define BUF_STATE_GET_USAGECOUNT(state) (((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT)
+#define BUF_STATE_GET_REFCOUNT(state) \
+	((uint32)((state) & BUF_REFCOUNT_MASK))
+#define BUF_STATE_GET_USAGECOUNT(state) \
+	((uint32)(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT))
 
 /*
  * Flags for buffer descriptors
@@ -65,17 +74,28 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  * Note: BM_TAG_VALID essentially means that there is a buffer hashtable
  * entry associated with the buffer's tag.
  */
-#define BM_LOCKED				(1U << 22)	/* buffer header is locked */
-#define BM_DIRTY				(1U << 23)	/* data needs writing */
-#define BM_VALID				(1U << 24)	/* data is valid */
-#define BM_TAG_VALID			(1U << 25)	/* tag is assigned */
-#define BM_IO_IN_PROGRESS		(1U << 26)	/* read or write in progress */
-#define BM_IO_ERROR				(1U << 27)	/* previous I/O failed */
-#define BM_JUST_DIRTIED			(1U << 28)	/* dirtied since write started */
-#define BM_PIN_COUNT_WAITER		(1U << 29)	/* have waiter for sole pin */
-#define BM_CHECKPOINT_NEEDED	(1U << 30)	/* must write for checkpoint */
-#define BM_PERMANENT			(1U << 31)	/* permanent buffer (not unlogged,
-											 * or init fork) */
+
+/* buffer header is locked */
+#define BM_LOCKED				(UINT64CONST(1) << 22)
+/* data needs writing */
+#define BM_DIRTY				(UINT64CONST(1) << 23)
+/* data is valid */
+#define BM_VALID				(UINT64CONST(1) << 24)
+/* tag is assigned */
+#define BM_TAG_VALID			(UINT64CONST(1) << 25)
+/* read or write in progress */
+#define BM_IO_IN_PROGRESS		(UINT64CONST(1) << 26)
+/* previous I/O failed */
+#define BM_IO_ERROR				(UINT64CONST(1) << 27)
+/* dirtied since write started */
+#define BM_JUST_DIRTIED			(UINT64CONST(1) << 28)
+/* have waiter for sole pin */
+#define BM_PIN_COUNT_WAITER		(UINT64CONST(1) << 29)
+/* must write for checkpoint */
+#define BM_CHECKPOINT_NEEDED	(UINT64CONST(1) << 30)
+/* permanent buffer (not unlogged, or init fork) */
+#define BM_PERMANENT			(UINT64CONST(1) << 31)
+
 /*
  * The maximum allowed value of usage_count represents a tradeoff between
  * accuracy and speed of the clock-sweep buffer management algorithm.  A
@@ -86,7 +106,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 #define BM_MAX_USAGE_COUNT	5
 
-StaticAssertDecl(BM_MAX_USAGE_COUNT < (1 << BUF_USAGECOUNT_BITS),
+StaticAssertDecl(BM_MAX_USAGE_COUNT < (UINT64CONST(1) << BUF_USAGECOUNT_BITS),
 				 "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
 StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
 				 "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
@@ -251,8 +271,8 @@ BufMappingPartitionLockByIndex(uint32 index)
  * We use this same struct for local buffer headers, but the locks are not
  * used and not all of the flag bits are useful either. To avoid unnecessary
  * overhead, manipulations of the state field should be done without actual
- * atomic operations (i.e. only pg_atomic_read_u32() and
- * pg_atomic_unlocked_write_u32()).
+ * atomic operations (i.e. only pg_atomic_read_u64() and
+ * pg_atomic_unlocked_write_u64()).
  *
  * Be careful to avoid increasing the size of the struct when adding or
  * reordering members.  Keeping it below 64 bytes (the most common CPU
@@ -280,7 +300,7 @@ typedef struct BufferDesc
 	 * State of the buffer, containing flags, refcount and usagecount. See
 	 * BUF_* and BM_* defines at the top of this file.
 	 */
-	pg_atomic_uint32 state;
+	pg_atomic_uint64 state;
 
 	/*
 	 * Backend of pin-count waiter. The buffer header spinlock needs to be
@@ -386,7 +406,7 @@ BufferDescriptorGetContentLock(const BufferDesc *bdesc)
  * Functions for acquiring/releasing a shared buffer header's spinlock.  Do
  * not apply these to local buffers!
  */
-extern uint32 LockBufHdr(BufferDesc *desc);
+extern uint64 LockBufHdr(BufferDesc *desc);
 
 /*
  * Unlock the buffer header.
@@ -397,9 +417,9 @@ extern uint32 LockBufHdr(BufferDesc *desc);
 static inline void
 UnlockBufHdr(BufferDesc *desc)
 {
-	Assert(pg_atomic_read_u32(&desc->state) & BM_LOCKED);
+	Assert(pg_atomic_read_u64(&desc->state) & BM_LOCKED);
 
-	pg_atomic_fetch_sub_u32(&desc->state, BM_LOCKED);
+	pg_atomic_fetch_sub_u64(&desc->state, BM_LOCKED);
 }
 
 /*
@@ -410,14 +430,14 @@ UnlockBufHdr(BufferDesc *desc)
  * Note that this approach would not work for usagecount, since we need to cap
  * the usagecount at BM_MAX_USAGE_COUNT.
  */
-static inline uint32
-UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
-				uint32 set_bits, uint32 unset_bits,
+static inline uint64
+UnlockBufHdrExt(BufferDesc *desc, uint64 old_buf_state,
+				uint64 set_bits, uint64 unset_bits,
 				int refcount_change)
 {
 	for (;;)
 	{
-		uint32		buf_state = old_buf_state;
+		uint64		buf_state = old_buf_state;
 
 		Assert(buf_state & BM_LOCKED);
 
@@ -428,7 +448,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 		if (refcount_change != 0)
 			buf_state += BUF_REFCOUNT_ONE * refcount_change;
 
-		if (pg_atomic_compare_exchange_u32(&desc->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&desc->state, &old_buf_state,
 										   buf_state))
 		{
 			return old_buf_state;
@@ -436,7 +456,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 	}
 }
 
-extern uint32 WaitBufHdrUnlocked(BufferDesc *buf);
+extern uint64 WaitBufHdrUnlocked(BufferDesc *buf);
 
 /* in bufmgr.c */
 
@@ -496,14 +516,14 @@ extern void TrackNewBufferPin(Buffer buf);
 
 /* solely to make it easier to write tests */
 extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
-extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 							  bool forget_owner, bool release_aio);
 
 
 /* freelist.c */
 extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
 extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
-									 uint32 *buf_state, bool *from_ring);
+									 uint64 *buf_state, bool *from_ring);
 extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
 								 BufferDesc *buf, bool from_ring);
 
@@ -539,7 +559,7 @@ extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
 										  uint32 *extended_by);
 extern void MarkLocalBufferDirty(Buffer buffer);
 extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
-								   uint32 set_flag_bits, bool release_aio);
+								   uint64 set_flag_bits, bool release_aio);
 extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
 extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
 extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
diff --git a/src/include/storage/procnumber.h b/src/include/storage/procnumber.h
index 2ddaaf0c646..6baac7c77f1 100644
--- a/src/include/storage/procnumber.h
+++ b/src/include/storage/procnumber.h
@@ -27,13 +27,13 @@ typedef int ProcNumber;
 
 /*
  * Note: MAX_BACKENDS_BITS is 18 as that is the space available for buffer
- * refcounts in buf_internals.h.  This limitation could be lifted by using a
- * 64bit state; but it's unlikely to be worthwhile as 2^18-1 backends exceed
- * currently realistic configurations. Even if that limitation were removed,
- * we still could not a) exceed 2^23-1 because inval.c stores the ProcNumber
- * as a 3-byte signed integer, b) INT_MAX/4 because some places compute
- * 4*MaxBackends without any overflow check.  We check that the configured
- * number of backends does not exceed MAX_BACKENDS in InitializeMaxBackends().
+ * refcounts in buf_internals.h.  This limitation could be lifted, but it's
+ * unlikely to be worthwhile as 2^18-1 backends exceed currently realistic
+ * configurations. Even if that limitation were removed, we still could not a)
+ * exceed 2^23-1 because inval.c stores the ProcNumber as a 3-byte signed
+ * integer, b) INT_MAX/4 because some places compute 4*MaxBackends without any
+ * overflow check.  We check that the configured number of backends does not
+ * exceed MAX_BACKENDS in InitializeMaxBackends().
  */
 #define MAX_BACKENDS_BITS		18
 #define MAX_BACKENDS			((1U << MAX_BACKENDS_BITS)-1)
diff --git a/src/backend/storage/buffer/buf_init.c b/src/backend/storage/buffer/buf_init.c
index 6fd3a6bbac5..25f71191ec3 100644
--- a/src/backend/storage/buffer/buf_init.c
+++ b/src/backend/storage/buffer/buf_init.c
@@ -121,7 +121,7 @@ BufferManagerShmemInit(void)
 
 			ClearBufferTag(&buf->tag);
 
-			pg_atomic_init_u32(&buf->state, 0);
+			pg_atomic_init_u64(&buf->state, 0);
 			buf->wait_backend_pgprocno = INVALID_PROC_NUMBER;
 
 			buf->buf_id = i;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index eb55102b0d7..03d99d294d5 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -780,7 +780,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 {
 	BufferDesc *bufHdr;
 	BufferTag	tag;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(recent_buffer));
 
@@ -793,7 +793,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 		int			b = -recent_buffer - 1;
 
 		bufHdr = GetLocalBufferDescriptor(b);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		/* Is it still valid and holding the right tag? */
 		if ((buf_state & BM_VALID) && BufferTagsEqual(&tag, &bufHdr->tag))
@@ -1386,8 +1386,8 @@ StartReadBuffersImpl(ReadBuffersOperation *operation,
 				bufHdr = GetLocalBufferDescriptor(-buffers[i] - 1);
 			else
 				bufHdr = GetBufferDescriptor(buffers[i] - 1);
-			Assert(pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID);
-			found = pg_atomic_read_u32(&bufHdr->state) & BM_VALID;
+			Assert(pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID);
+			found = pg_atomic_read_u64(&bufHdr->state) & BM_VALID;
 		}
 		else
 		{
@@ -1613,10 +1613,10 @@ CheckReadBuffersOperation(ReadBuffersOperation *operation, bool is_complete)
 			GetBufferDescriptor(buffer - 1);
 
 		Assert(BufferGetBlockNumber(buffer) == operation->blocknum + i);
-		Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_TAG_VALID);
+		Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_TAG_VALID);
 
 		if (i < operation->nblocks_done)
-			Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_VALID);
+			Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_VALID);
 	}
 #endif
 }
@@ -2083,8 +2083,8 @@ BufferAlloc(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 	int			existing_buf_id;
 	Buffer		victim_buffer;
 	BufferDesc *victim_buf_hdr;
-	uint32		victim_buf_state;
-	uint32		set_bits = 0;
+	uint64		victim_buf_state;
+	uint64		set_bits = 0;
 
 	/* Make sure we will have room to remember the buffer pin */
 	ResourceOwnerEnlarge(CurrentResourceOwner);
@@ -2251,7 +2251,7 @@ InvalidateBuffer(BufferDesc *buf)
 	uint32		oldHash;		/* hash value for oldTag */
 	LWLock	   *oldPartitionLock;	/* buffer partition lock for it */
 	uint32		oldFlags;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/* Save the original buffer tag before dropping the spinlock */
 	oldTag = buf->tag;
@@ -2342,7 +2342,7 @@ retry:
 static bool
 InvalidateVictimBuffer(BufferDesc *buf_hdr)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	uint32		hash;
 	LWLock	   *partition_lock;
 	BufferTag	tag;
@@ -2402,10 +2402,10 @@ InvalidateVictimBuffer(BufferDesc *buf_hdr)
 
 	LWLockRelease(partition_lock);
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	Assert(!(buf_state & (BM_DIRTY | BM_VALID | BM_TAG_VALID)));
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
-	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u32(&buf_hdr->state)) > 0);
+	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u64(&buf_hdr->state)) > 0);
 
 	return true;
 }
@@ -2415,7 +2415,7 @@ GetVictimBuffer(BufferAccessStrategy strategy, IOContext io_context)
 {
 	BufferDesc *buf_hdr;
 	Buffer		buf;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		from_ring;
 
 	/*
@@ -2548,7 +2548,7 @@ again:
 
 	/* a final set of sanity checks */
 #ifdef USE_ASSERT_CHECKING
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) == 1);
 	Assert(!(buf_state & (BM_TAG_VALID | BM_VALID | BM_DIRTY)));
@@ -2839,13 +2839,13 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
 			 */
 			do
 			{
-				pg_atomic_fetch_and_u32(&existing_hdr->state, ~BM_VALID);
+				pg_atomic_fetch_and_u64(&existing_hdr->state, ~BM_VALID);
 			} while (!StartBufferIO(existing_hdr, true, false));
 		}
 		else
 		{
-			uint32		buf_state;
-			uint32		set_bits = 0;
+			uint64		buf_state;
+			uint64		set_bits = 0;
 
 			buf_state = LockBufHdr(victim_buf_hdr);
 
@@ -3021,7 +3021,7 @@ BufferIsDirty(Buffer buffer)
 		Assert(BufferIsLockedByMeInMode(buffer, BUFFER_LOCK_EXCLUSIVE));
 	}
 
-	return pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY;
+	return pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY;
 }
 
 /*
@@ -3037,8 +3037,8 @@ void
 MarkBufferDirty(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
-	uint32		old_buf_state;
+	uint64		buf_state;
+	uint64		old_buf_state;
 
 	if (!BufferIsValid(buffer))
 		elog(ERROR, "bad buffer ID: %d", buffer);
@@ -3058,7 +3058,7 @@ MarkBufferDirty(Buffer buffer)
 	 * NB: We have to wait for the buffer header spinlock to be not held, as
 	 * TerminateBufferIO() relies on the spinlock.
 	 */
-	old_buf_state = pg_atomic_read_u32(&bufHdr->state);
+	old_buf_state = pg_atomic_read_u64(&bufHdr->state);
 	for (;;)
 	{
 		if (old_buf_state & BM_LOCKED)
@@ -3069,7 +3069,7 @@ MarkBufferDirty(Buffer buffer)
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state |= BM_DIRTY | BM_JUST_DIRTIED;
 
-		if (pg_atomic_compare_exchange_u32(&bufHdr->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&bufHdr->state, &old_buf_state,
 										   buf_state))
 			break;
 	}
@@ -3173,10 +3173,10 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 
 	if (ref == NULL)
 	{
-		uint32		buf_state;
-		uint32		old_buf_state;
+		uint64		buf_state;
+		uint64		old_buf_state;
 
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			if (unlikely(skip_if_not_valid && !(old_buf_state & BM_VALID)))
@@ -3210,7 +3210,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 					buf_state += BUF_USAGECOUNT_ONE;
 			}
 
-			if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+			if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 											   buf_state))
 			{
 				result = (buf_state & BM_VALID) != 0;
@@ -3237,7 +3237,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 		 * that the buffer page is legitimately non-accessible here.  We
 		 * cannot meddle with that.
 		 */
-		result = (pg_atomic_read_u32(&buf->state) & BM_VALID) != 0;
+		result = (pg_atomic_read_u64(&buf->state) & BM_VALID) != 0;
 
 		Assert(ref->data.refcount > 0);
 		ref->data.refcount++;
@@ -3272,7 +3272,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 static void
 PinBuffer_Locked(BufferDesc *buf)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	/*
 	 * As explained, We don't expect any preexisting pins. That allows us to
@@ -3284,7 +3284,7 @@ PinBuffer_Locked(BufferDesc *buf)
 	 * Since we hold the buffer spinlock, we can update the buffer state and
 	 * release the lock in one operation.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 
 	UnlockBufHdrExt(buf, old_buf_state,
 					0, 0, 1);
@@ -3314,7 +3314,7 @@ WakePinCountWaiter(BufferDesc *buf)
 	 * BM_PIN_COUNT_WAITER if it stops waiting for a reason other than this
 	 * backend waking it up.
 	 */
-	uint32		buf_state = LockBufHdr(buf);
+	uint64		buf_state = LockBufHdr(buf);
 
 	if ((buf_state & BM_PIN_COUNT_WAITER) &&
 		BUF_STATE_GET_REFCOUNT(buf_state) == 1)
@@ -3361,7 +3361,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 	ref->data.refcount--;
 	if (ref->data.refcount == 0)
 	{
-		uint32		old_buf_state;
+		uint64		old_buf_state;
 
 		/*
 		 * Mark buffer non-accessible to Valgrind.
@@ -3379,7 +3379,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 		Assert(!LWLockHeldByMe(BufferDescriptorGetContentLock(buf)));
 
 		/* decrement the shared reference count */
-		old_buf_state = pg_atomic_fetch_sub_u32(&buf->state, BUF_REFCOUNT_ONE);
+		old_buf_state = pg_atomic_fetch_sub_u64(&buf->state, BUF_REFCOUNT_ONE);
 
 		/* Support LockBufferForCleanup() */
 		if (old_buf_state & BM_PIN_COUNT_WAITER)
@@ -3436,7 +3436,7 @@ TrackNewBufferPin(Buffer buf)
 static void
 BufferSync(int flags)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	int			buf_id;
 	int			num_to_scan;
 	int			num_spaces;
@@ -3446,7 +3446,7 @@ BufferSync(int flags)
 	Oid			last_tsid;
 	binaryheap *ts_heap;
 	int			i;
-	uint32		mask = BM_DIRTY;
+	uint64		mask = BM_DIRTY;
 	WritebackContext wb_context;
 
 	/*
@@ -3478,7 +3478,7 @@ BufferSync(int flags)
 	for (buf_id = 0; buf_id < NBuffers; buf_id++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
-		uint32		set_bits = 0;
+		uint64		set_bits = 0;
 
 		/*
 		 * Header spinlock is enough to examine BM_DIRTY, see comment in
@@ -3645,7 +3645,7 @@ BufferSync(int flags)
 		 * write the buffer though we didn't need to.  It doesn't seem worth
 		 * guarding against this, though.
 		 */
-		if (pg_atomic_read_u32(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
+		if (pg_atomic_read_u64(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
 		{
 			if (SyncOneBuffer(buf_id, false, &wb_context) & BUF_WRITTEN)
 			{
@@ -4015,7 +4015,7 @@ SyncOneBuffer(int buf_id, bool skip_recently_used, WritebackContext *wb_context)
 {
 	BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
 	int			result = 0;
-	uint32		buf_state;
+	uint64		buf_state;
 	BufferTag	tag;
 
 	/* Make sure we can handle the pin */
@@ -4264,7 +4264,7 @@ DebugPrintBufferRefcount(Buffer buffer)
 	int32		loccount;
 	char	   *result;
 	ProcNumber	backend;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
@@ -4281,9 +4281,9 @@ DebugPrintBufferRefcount(Buffer buffer)
 	}
 
 	/* theoretically we should lock the bufhdr here */
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
-	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
+	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%" PRIx64 ", refcount=%u %d)",
 					  buffer,
 					  relpathbackend(BufTagGetRelFileLocator(&buf->tag), backend,
 									 BufTagGetForkNum(&buf->tag)).str,
@@ -4383,7 +4383,7 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
 	instr_time	io_start;
 	Block		bufBlock;
 	char	   *bufToWrite;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * Try to start an I/O operation.  If StartBufferIO returns false, then
@@ -4581,7 +4581,7 @@ BufferIsPermanent(Buffer buffer)
 	 * not random garbage.
 	 */
 	bufHdr = GetBufferDescriptor(buffer - 1);
-	return (pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT) != 0;
+	return (pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT) != 0;
 }
 
 /*
@@ -5044,11 +5044,11 @@ FlushRelationBuffers(Relation rel)
 	{
 		for (i = 0; i < NLocBuffer; i++)
 		{
-			uint32		buf_state;
+			uint64		buf_state;
 
 			bufHdr = GetLocalBufferDescriptor(i);
 			if (BufTagMatchesRelFileLocator(&bufHdr->tag, &rel->rd_locator) &&
-				((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
+				((buf_state = pg_atomic_read_u64(&bufHdr->state)) &
 				 (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
 			{
 				ErrorContextCallback errcallback;
@@ -5084,7 +5084,7 @@ FlushRelationBuffers(Relation rel)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5156,7 +5156,7 @@ FlushRelationsAllBuffers(SMgrRelation *smgrs, int nrels)
 	{
 		SMgrSortArray *srelent = NULL;
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * As in DropRelationBuffers, an unlocked precheck should be safe and
@@ -5405,7 +5405,7 @@ FlushDatabaseBuffers(Oid dbid)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5553,13 +5553,13 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 	 * is only intended to be used in cases where failing to write out the
 	 * data would be harmless anyway, it doesn't really matter.
 	 */
-	if ((pg_atomic_read_u32(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
+	if ((pg_atomic_read_u64(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
 		(BM_DIRTY | BM_JUST_DIRTIED))
 	{
 		XLogRecPtr	lsn = InvalidXLogRecPtr;
 		bool		dirtied = false;
 		bool		delayChkptFlags = false;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * If we need to protect hint bit updates from torn writes, WAL-log a
@@ -5571,7 +5571,7 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 		 * when we call XLogInsert() since the value changes dynamically.
 		 */
 		if (XLogHintBitIsNeeded() &&
-			(pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT))
+			(pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT))
 		{
 			/*
 			 * If we must not write WAL, due to a relfilelocator-specific
@@ -5671,8 +5671,8 @@ UnlockBuffers(void)
 
 	if (buf)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		buf_state = LockBufHdr(buf);
 
@@ -5803,8 +5803,8 @@ LockBufferForCleanup(Buffer buffer)
 
 	for (;;)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -5952,7 +5952,7 @@ bool
 ConditionalLockBufferForCleanup(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state,
+	uint64		buf_state,
 				refcount;
 
 	Assert(BufferIsValid(buffer));
@@ -6010,7 +6010,7 @@ bool
 IsBufferCleanupOK(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 
@@ -6066,7 +6066,7 @@ WaitIO(BufferDesc *buf)
 	ConditionVariablePrepareToSleep(cv);
 	for (;;)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 		PgAioWaitRef iow;
 
 		/*
@@ -6140,7 +6140,7 @@ WaitIO(BufferDesc *buf)
 bool
 StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	ResourceOwnerEnlarge(CurrentResourceOwner);
 
@@ -6196,11 +6196,11 @@ StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
  * is being released)
  */
 void
-TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 				  bool forget_owner, bool release_aio)
 {
-	uint32		buf_state;
-	uint32		unset_flag_bits = 0;
+	uint64		buf_state;
+	uint64		unset_flag_bits = 0;
 	int			refcount_change = 0;
 
 	buf_state = LockBufHdr(buf);
@@ -6261,7 +6261,7 @@ static void
 AbortBufferIO(Buffer buffer)
 {
 	BufferDesc *buf_hdr = GetBufferDescriptor(buffer - 1);
-	uint32		buf_state;
+	uint64		buf_state;
 
 	buf_state = LockBufHdr(buf_hdr);
 	Assert(buf_state & (BM_IO_IN_PROGRESS | BM_TAG_VALID));
@@ -6355,10 +6355,10 @@ rlocator_comparator(const void *p1, const void *p2)
 /*
  * Lock buffer header - set BM_LOCKED in buffer state.
  */
-uint32
+uint64
 LockBufHdr(BufferDesc *desc)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	Assert(!BufferIsLocal(BufferDescriptorGetBuffer(desc)));
 
@@ -6369,7 +6369,7 @@ LockBufHdr(BufferDesc *desc)
 		 * the spin-delay infrastructure. The work necessary for that shows up
 		 * in profiles and is rarely necessary.
 		 */
-		old_buf_state = pg_atomic_fetch_or_u32(&desc->state, BM_LOCKED);
+		old_buf_state = pg_atomic_fetch_or_u64(&desc->state, BM_LOCKED);
 		if (likely(!(old_buf_state & BM_LOCKED)))
 			break;				/* got lock */
 
@@ -6382,7 +6382,7 @@ LockBufHdr(BufferDesc *desc)
 			while (old_buf_state & BM_LOCKED)
 			{
 				perform_spin_delay(&delayStatus);
-				old_buf_state = pg_atomic_read_u32(&desc->state);
+				old_buf_state = pg_atomic_read_u64(&desc->state);
 			}
 			finish_spin_delay(&delayStatus);
 		}
@@ -6403,20 +6403,20 @@ LockBufHdr(BufferDesc *desc)
  * Obviously the buffer could be locked by the time the value is returned, so
  * this is primarily useful in CAS style loops.
  */
-pg_noinline uint32
+pg_noinline uint64
 WaitBufHdrUnlocked(BufferDesc *buf)
 {
 	SpinDelayStatus delayStatus;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	init_local_spin_delay(&delayStatus);
 
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
 	while (buf_state & BM_LOCKED)
 	{
 		perform_spin_delay(&delayStatus);
-		buf_state = pg_atomic_read_u32(&buf->state);
+		buf_state = pg_atomic_read_u64(&buf->state);
 	}
 
 	finish_spin_delay(&delayStatus);
@@ -6704,12 +6704,12 @@ ResOwnerPrintBufferPin(Datum res)
 static bool
 EvictUnpinnedBufferInternal(BufferDesc *desc, bool *buffer_flushed)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result;
 
 	*buffer_flushed = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -6803,12 +6803,12 @@ EvictAllUnpinnedBuffers(int32 *buffers_evicted, int32 *buffers_flushed,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -6855,7 +6855,7 @@ EvictRelUnpinnedBuffers(Relation rel, int32 *buffers_evicted,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
@@ -6897,12 +6897,12 @@ static bool
 MarkDirtyUnpinnedBufferInternal(Buffer buf, BufferDesc *desc,
 								bool *buffer_already_dirty)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result = false;
 
 	*buffer_already_dirty = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -7000,7 +7000,7 @@ MarkDirtyRelUnpinnedBuffers(Relation rel,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
@@ -7054,12 +7054,12 @@ MarkDirtyAllUnpinnedBuffers(int32 *buffers_dirtied,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -7110,7 +7110,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		BufferDesc *buf_hdr = is_temp ?
 			GetLocalBufferDescriptor(-buffer - 1)
 			: GetBufferDescriptor(buffer - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * Check that all the buffers are actually ones that could conceivably
@@ -7128,7 +7128,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		}
 
 		if (is_temp)
-			buf_state = pg_atomic_read_u32(&buf_hdr->state);
+			buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		else
 			buf_state = LockBufHdr(buf_hdr);
 
@@ -7166,7 +7166,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		if (is_temp)
 		{
 			buf_state += BUF_REFCOUNT_ONE;
-			pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 		}
 		else
 			UnlockBufHdrExt(buf_hdr, buf_state, 0, 0, 1);
@@ -7352,13 +7352,13 @@ buffer_readv_complete_one(PgAioTargetData *td, uint8 buf_off, Buffer buffer,
 		: GetBufferDescriptor(buffer - 1);
 	BufferTag	tag = buf_hdr->tag;
 	char	   *bufdata = BufferGetBlock(buffer);
-	uint32		set_flag_bits;
+	uint64		set_flag_bits;
 	int			piv_flags;
 
 	/* check that the buffer is in the expected state for a read */
 #ifdef USE_ASSERT_CHECKING
 	{
-		uint32		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 		Assert(buf_state & BM_TAG_VALID);
 		Assert(!(buf_state & BM_VALID));
diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 28d952b3534..1d4f19a9afd 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -86,7 +86,7 @@ typedef struct BufferAccessStrategyData
 
 /* Prototypes for internal functions */
 static BufferDesc *GetBufferFromRing(BufferAccessStrategy strategy,
-									 uint32 *buf_state);
+									 uint64 *buf_state);
 static void AddBufferToRing(BufferAccessStrategy strategy,
 							BufferDesc *buf);
 
@@ -171,7 +171,7 @@ ClockSweepTick(void)
  *	before returning.
  */
 BufferDesc *
-StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_ring)
+StrategyGetBuffer(BufferAccessStrategy strategy, uint64 *buf_state, bool *from_ring)
 {
 	BufferDesc *buf;
 	int			bgwprocno;
@@ -230,8 +230,8 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 	trycounter = NBuffers;
 	for (;;)
 	{
-		uint32		old_buf_state;
-		uint32		local_buf_state;
+		uint64		old_buf_state;
+		uint64		local_buf_state;
 
 		buf = GetBufferDescriptor(ClockSweepTick());
 
@@ -239,7 +239,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 		 * Check whether the buffer can be used and pin it if so. Do this
 		 * using a CAS loop, to avoid having to lock the buffer header.
 		 */
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			local_buf_state = old_buf_state;
@@ -277,7 +277,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 			{
 				local_buf_state -= BUF_USAGECOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					trycounter = NBuffers;
@@ -289,7 +289,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 				/* pin the buffer if the CAS succeeds */
 				local_buf_state += BUF_REFCOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					/* Found a usable buffer */
@@ -655,12 +655,12 @@ FreeAccessStrategy(BufferAccessStrategy strategy)
  * returning.
  */
 static BufferDesc *
-GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
+GetBufferFromRing(BufferAccessStrategy strategy, uint64 *buf_state)
 {
 	BufferDesc *buf;
 	Buffer		bufnum;
-	uint32		old_buf_state;
-	uint32		local_buf_state;	/* to avoid repeated (de-)referencing */
+	uint64		old_buf_state;
+	uint64		local_buf_state;	/* to avoid repeated (de-)referencing */
 
 
 	/* Advance to next ring slot */
@@ -682,7 +682,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 	 * Check whether the buffer can be used and pin it if so. Do this using a
 	 * CAS loop, to avoid having to lock the buffer header.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 	for (;;)
 	{
 		local_buf_state = old_buf_state;
@@ -710,7 +710,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 		/* pin the buffer if the CAS succeeds */
 		local_buf_state += BUF_REFCOUNT_ONE;
 
-		if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 										   local_buf_state))
 		{
 			*buf_state = local_buf_state;
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index 15aac7d1c9f..a41a5facd3a 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -148,7 +148,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	}
 	else
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		victim_buffer = GetLocalVictimBuffer();
 		bufid = -victim_buffer - 1;
@@ -165,10 +165,10 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		 */
 		bufHdr->tag = newTag;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		buf_state &= ~(BUF_FLAG_MASK | BUF_USAGECOUNT_MASK);
 		buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 		*foundPtr = false;
 	}
@@ -245,12 +245,12 @@ GetLocalVictimBuffer(void)
 
 		if (LocalRefCount[victim_bufid] == 0)
 		{
-			uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 			if (BUF_STATE_GET_USAGECOUNT(buf_state) > 0)
 			{
 				buf_state -= BUF_USAGECOUNT_ONE;
-				pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+				pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 				trycounter = NLocBuffer;
 			}
 			else if (BUF_STATE_GET_REFCOUNT(buf_state) > 0)
@@ -286,13 +286,13 @@ GetLocalVictimBuffer(void)
 	 * this buffer is not referenced but it might still be dirty. if that's
 	 * the case, write it out before reusing it!
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY)
 		FlushLocalBuffer(bufHdr, NULL);
 
 	/*
 	 * Remove the victim buffer from the hashtable and mark as invalid.
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID)
 	{
 		InvalidateLocalBuffer(bufHdr, false);
 
@@ -417,7 +417,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 		if (found)
 		{
 			BufferDesc *existing_hdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			UnpinLocalBuffer(BufferDescriptorGetBuffer(victim_buf_hdr));
 
@@ -428,18 +428,18 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 			/*
 			 * Clear the BM_VALID bit, do StartLocalBufferIO() and proceed.
 			 */
-			buf_state = pg_atomic_read_u32(&existing_hdr->state);
+			buf_state = pg_atomic_read_u64(&existing_hdr->state);
 			Assert(buf_state & BM_TAG_VALID);
 			Assert(!(buf_state & BM_DIRTY));
 			buf_state &= ~BM_VALID;
-			pg_atomic_unlocked_write_u32(&existing_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&existing_hdr->state, buf_state);
 
 			/* no need to loop for local buffers */
 			StartLocalBufferIO(existing_hdr, true, false);
 		}
 		else
 		{
-			uint32		buf_state = pg_atomic_read_u32(&victim_buf_hdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&victim_buf_hdr->state);
 
 			Assert(!(buf_state & (BM_VALID | BM_TAG_VALID | BM_DIRTY | BM_JUST_DIRTIED)));
 
@@ -447,7 +447,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 
 			buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
 
-			pg_atomic_unlocked_write_u32(&victim_buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&victim_buf_hdr->state, buf_state);
 
 			hresult->id = victim_buf_id;
 
@@ -467,13 +467,13 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 	{
 		Buffer		buf = buffers[i];
 		BufferDesc *buf_hdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		buf_state |= BM_VALID;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 
 	*extended_by = extend_by;
@@ -492,7 +492,7 @@ MarkLocalBufferDirty(Buffer buffer)
 {
 	int			bufid;
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsLocal(buffer));
 
@@ -506,14 +506,14 @@ MarkLocalBufferDirty(Buffer buffer)
 
 	bufHdr = GetLocalBufferDescriptor(bufid);
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	if (!(buf_state & BM_DIRTY))
 		pgBufferUsage.local_blks_dirtied++;
 
 	buf_state |= BM_DIRTY;
 
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -522,7 +522,7 @@ MarkLocalBufferDirty(Buffer buffer)
 bool
 StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * With AIO the buffer could have IO in progress, e.g. when there are two
@@ -542,7 +542,7 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 	/* Once we get here, there is definitely no I/O active on this buffer */
 
 	/* Check if someone else already did the I/O */
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 	if (forInput ? (buf_state & BM_VALID) : !(buf_state & BM_DIRTY))
 	{
 		return false;
@@ -559,11 +559,11 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
  * Like TerminateBufferIO, but for local buffers
  */
 void
-TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bits,
+TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint64 set_flag_bits,
 					   bool release_aio)
 {
 	/* Only need to adjust flags */
-	uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+	uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/* BM_IO_IN_PROGRESS isn't currently used for local buffers */
 
@@ -582,7 +582,7 @@ TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bit
 	}
 
 	buf_state |= set_flag_bits;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 	/* local buffers don't track IO using resowners */
 
@@ -606,7 +606,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 {
 	Buffer		buffer = BufferDescriptorGetBuffer(bufHdr);
 	int			bufid = -buffer - 1;
-	uint32		buf_state;
+	uint64		buf_state;
 	LocalBufferLookupEnt *hresult;
 
 	/*
@@ -622,7 +622,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 		Assert(!pgaio_wref_valid(&bufHdr->io_wref));
 	}
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/*
 	 * We need to test not just LocalRefCount[bufid] but also the BufferDesc
@@ -647,7 +647,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 	ClearBufferTag(&bufHdr->tag);
 	buf_state &= ~BUF_FLAG_MASK;
 	buf_state &= ~BUF_USAGECOUNT_MASK;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -671,9 +671,9 @@ DropRelationLocalBuffers(RelFileLocator rlocator, ForkNumber *forkNum,
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (!(buf_state & BM_TAG_VALID) ||
 			!BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -706,9 +706,9 @@ DropRelationAllLocalBuffers(RelFileLocator rlocator)
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if ((buf_state & BM_TAG_VALID) &&
 			BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -804,11 +804,11 @@ InitLocalBuffers(void)
 bool
 PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	Buffer		buffer = BufferDescriptorGetBuffer(buf_hdr);
 	int			bufid = -buffer - 1;
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	if (LocalRefCount[bufid] == 0)
 	{
@@ -819,7 +819,7 @@ PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 		{
 			buf_state += BUF_USAGECOUNT_ONE;
 		}
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/*
 		 * See comment in PinBuffer().
@@ -856,14 +856,14 @@ UnpinLocalBufferNoOwner(Buffer buffer)
 	if (--LocalRefCount[buffid] == 0)
 	{
 		BufferDesc *buf_hdr = GetLocalBufferDescriptor(buffid);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		NLocalPinnedBuffers--;
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state -= BUF_REFCOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/* see comment in UnpinBufferNoOwner */
 		VALGRIND_MAKE_MEM_NOACCESS(LocalBufHdrGetBlock(buf_hdr), BLCKSZ);
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index 0c58e4b265c..529803346ce 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -199,7 +199,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 		for (i = 0; i < NBuffers; i++)
 		{
 			BufferDesc *bufHdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			CHECK_FOR_INTERRUPTS();
 
@@ -615,7 +615,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		CHECK_FOR_INTERRUPTS();
 
@@ -626,7 +626,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 		 * noticeably increase the cost of the function.
 		 */
 		bufHdr = GetBufferDescriptor(i);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (buf_state & BM_VALID)
 		{
@@ -676,7 +676,7 @@ pg_buffercache_usage_counts(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		int			usage_count;
 
 		CHECK_FOR_INTERRUPTS();
diff --git a/src/test/modules/test_aio/test_aio.c b/src/test/modules/test_aio/test_aio.c
index d7eadeab256..488d98e7e66 100644
--- a/src/test/modules/test_aio/test_aio.c
+++ b/src/test/modules/test_aio/test_aio.c
@@ -308,9 +308,9 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 {
 	Buffer		buf;
 	BufferDesc *buf_hdr;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		was_pinned = false;
-	uint32		unset_bits = 0;
+	uint64		unset_bits = 0;
 
 	/* place buffer in shared buffers without erroring out */
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_ZERO_AND_LOCK, NULL);
@@ -319,7 +319,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	}
 	else
 	{
@@ -340,7 +340,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_state &= ~unset_bits;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 	else
 	{
@@ -489,7 +489,7 @@ invalidate_rel_block(PG_FUNCTION_ARGS)
 
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-			if (pg_atomic_read_u32(&buf_hdr->state) & BM_DIRTY)
+			if (pg_atomic_read_u64(&buf_hdr->state) & BM_DIRTY)
 			{
 				if (BufferIsLocal(buf))
 					FlushLocalBuffer(buf_hdr, NULL);
@@ -572,7 +572,7 @@ buffer_call_terminate_io(PG_FUNCTION_ARGS)
 	bool		io_error = PG_GETARG_BOOL(3);
 	bool		release_aio = PG_GETARG_BOOL(4);
 	bool		clear_dirty = false;
-	uint32		set_flag_bits = 0;
+	uint64		set_flag_bits = 0;
 
 	if (io_error)
 		set_flag_bits |= BM_IO_ERROR;
-- 
2.48.1.76.g4e746b1a31.dirty


--lbbj3oq7cjvyhmbk
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v8-0007-bufmgr-Implement-buffer-content-locks-independent.patch"



^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* [PATCH v9 06/10] bufmgr: Change BufferDesc.state to be a 64bit atomic
@ 2026-01-07 22:26  Andres Freund <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Andres Freund @ 2026-01-07 22:26 UTC (permalink / raw)

This is motivated by wanting to merge buffer content locks into
BufferDesc.state in a future commit, rather than having a separate lwlock (see
commit c75ebc657ff more details). As this change is rather mechanical, it
seems to make sense to split it out into a separate commit, for easier review.

Reviewed-by: Melanie Plageman <[email protected]>
Discussion: https://postgr.es/m/fvfmkr5kk4nyex56ejgxj3uzi63isfxovp2biecb4bspbjrze7@az2pljabhnff
---
 src/include/storage/buf_internals.h           |  51 +++---
 src/include/storage/procnumber.h              |  14 +-
 src/backend/storage/buffer/buf_init.c         |   2 +-
 src/backend/storage/buffer/bufmgr.c           | 170 +++++++++---------
 src/backend/storage/buffer/freelist.c         |  24 +--
 src/backend/storage/buffer/localbuf.c         |  72 ++++----
 contrib/pg_buffercache/pg_buffercache_pages.c |   8 +-
 src/test/modules/test_aio/test_aio.c          |  12 +-
 8 files changed, 178 insertions(+), 175 deletions(-)

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index 2f607ea2ac5..a4d36e9ca01 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -30,7 +30,7 @@
 #include "utils/resowner.h"
 
 /*
- * Buffer state is a single 32-bit variable where following data is combined.
+ * Buffer state is a single 64-bit variable where following data is combined.
  *
  * State of the buffer itself (in order):
  * - 18 bits refcount
@@ -40,6 +40,9 @@
  * Combining these values allows to perform some operations without locking
  * the buffer header, by modifying them together with a CAS loop.
  *
+ * NB: A future commit will use a significant portion of the remaining bits to
+ * implement buffer locking as part of the state variable.
+ *
  * The definition of buffer state components is below.
  */
 #define BUF_REFCOUNT_BITS 18
@@ -52,27 +55,27 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
 /* refcount related definitions */
 #define BUF_REFCOUNT_ONE 1
 #define BUF_REFCOUNT_MASK \
-	((1U << BUF_REFCOUNT_BITS) - 1)
+	((UINT64CONST(1) << BUF_REFCOUNT_BITS) - 1)
 
 /* usage count related definitions */
 #define BUF_USAGECOUNT_SHIFT \
 	BUF_REFCOUNT_BITS
 #define BUF_USAGECOUNT_MASK \
-	(((1U << BUF_USAGECOUNT_BITS) - 1) << (BUF_USAGECOUNT_SHIFT))
+	(((UINT64CONST(1) << BUF_USAGECOUNT_BITS) - 1) << (BUF_USAGECOUNT_SHIFT))
 #define BUF_USAGECOUNT_ONE \
-	(1U << BUF_REFCOUNT_BITS)
+	(UINT64CONST(1) << BUF_REFCOUNT_BITS)
 
 /* flags related definitions */
 #define BUF_FLAG_SHIFT \
 	(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS)
 #define BUF_FLAG_MASK \
-	(((1U << BUF_FLAG_BITS) - 1) << BUF_FLAG_SHIFT)
+	(((UINT64CONST(1) << BUF_FLAG_BITS) - 1) << BUF_FLAG_SHIFT)
 
 /* Get refcount and usagecount from buffer state */
 #define BUF_STATE_GET_REFCOUNT(state) \
-	((state) & BUF_REFCOUNT_MASK)
+	((uint32)((state) & BUF_REFCOUNT_MASK))
 #define BUF_STATE_GET_USAGECOUNT(state) \
-	(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT)
+	((uint32)(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT))
 
 /*
  * Flags for buffer descriptors
@@ -82,7 +85,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 
 #define BUF_DEFINE_FLAG(flagno)	\
-	(1U << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + (flagno)))
+	(UINT64CONST(1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + (flagno)))
 
 /* buffer header is locked */
 #define BM_LOCKED					BUF_DEFINE_FLAG( 0)
@@ -115,7 +118,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 #define BM_MAX_USAGE_COUNT	5
 
-StaticAssertDecl(BM_MAX_USAGE_COUNT < (1 << BUF_USAGECOUNT_BITS),
+StaticAssertDecl(BM_MAX_USAGE_COUNT < (UINT64CONST(1) << BUF_USAGECOUNT_BITS),
 				 "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
 StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
 				 "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
@@ -280,8 +283,8 @@ BufMappingPartitionLockByIndex(uint32 index)
  * We use this same struct for local buffer headers, but the locks are not
  * used and not all of the flag bits are useful either. To avoid unnecessary
  * overhead, manipulations of the state field should be done without actual
- * atomic operations (i.e. only pg_atomic_read_u32() and
- * pg_atomic_unlocked_write_u32()).
+ * atomic operations (i.e. only pg_atomic_read_u64() and
+ * pg_atomic_unlocked_write_u64()).
  *
  * Be careful to avoid increasing the size of the struct when adding or
  * reordering members.  Keeping it below 64 bytes (the most common CPU
@@ -309,7 +312,7 @@ typedef struct BufferDesc
 	 * State of the buffer, containing flags, refcount and usagecount. See
 	 * BUF_* and BM_* defines at the top of this file.
 	 */
-	pg_atomic_uint32 state;
+	pg_atomic_uint64 state;
 
 	/*
 	 * Backend of pin-count waiter. The buffer header spinlock needs to be
@@ -415,7 +418,7 @@ BufferDescriptorGetContentLock(const BufferDesc *bdesc)
  * Functions for acquiring/releasing a shared buffer header's spinlock.  Do
  * not apply these to local buffers!
  */
-extern uint32 LockBufHdr(BufferDesc *desc);
+extern uint64 LockBufHdr(BufferDesc *desc);
 
 /*
  * Unlock the buffer header.
@@ -426,9 +429,9 @@ extern uint32 LockBufHdr(BufferDesc *desc);
 static inline void
 UnlockBufHdr(BufferDesc *desc)
 {
-	Assert(pg_atomic_read_u32(&desc->state) & BM_LOCKED);
+	Assert(pg_atomic_read_u64(&desc->state) & BM_LOCKED);
 
-	pg_atomic_fetch_sub_u32(&desc->state, BM_LOCKED);
+	pg_atomic_fetch_sub_u64(&desc->state, BM_LOCKED);
 }
 
 /*
@@ -439,14 +442,14 @@ UnlockBufHdr(BufferDesc *desc)
  * Note that this approach would not work for usagecount, since we need to cap
  * the usagecount at BM_MAX_USAGE_COUNT.
  */
-static inline uint32
-UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
-				uint32 set_bits, uint32 unset_bits,
+static inline uint64
+UnlockBufHdrExt(BufferDesc *desc, uint64 old_buf_state,
+				uint64 set_bits, uint64 unset_bits,
 				int refcount_change)
 {
 	for (;;)
 	{
-		uint32		buf_state = old_buf_state;
+		uint64		buf_state = old_buf_state;
 
 		Assert(buf_state & BM_LOCKED);
 
@@ -457,7 +460,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 		if (refcount_change != 0)
 			buf_state += BUF_REFCOUNT_ONE * refcount_change;
 
-		if (pg_atomic_compare_exchange_u32(&desc->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&desc->state, &old_buf_state,
 										   buf_state))
 		{
 			return old_buf_state;
@@ -465,7 +468,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 	}
 }
 
-extern uint32 WaitBufHdrUnlocked(BufferDesc *buf);
+extern uint64 WaitBufHdrUnlocked(BufferDesc *buf);
 
 /* in bufmgr.c */
 
@@ -525,14 +528,14 @@ extern void TrackNewBufferPin(Buffer buf);
 
 /* solely to make it easier to write tests */
 extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
-extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 							  bool forget_owner, bool release_aio);
 
 
 /* freelist.c */
 extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
 extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
-									 uint32 *buf_state, bool *from_ring);
+									 uint64 *buf_state, bool *from_ring);
 extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
 								 BufferDesc *buf, bool from_ring);
 
@@ -568,7 +571,7 @@ extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
 										  uint32 *extended_by);
 extern void MarkLocalBufferDirty(Buffer buffer);
 extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
-								   uint32 set_flag_bits, bool release_aio);
+								   uint64 set_flag_bits, bool release_aio);
 extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
 extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
 extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
diff --git a/src/include/storage/procnumber.h b/src/include/storage/procnumber.h
index 30c360ad350..bd9cb3891cc 100644
--- a/src/include/storage/procnumber.h
+++ b/src/include/storage/procnumber.h
@@ -27,13 +27,13 @@ typedef int ProcNumber;
 
 /*
  * Note: MAX_BACKENDS_BITS is 18 as that is the space available for buffer
- * refcounts in buf_internals.h.  This limitation could be lifted by using a
- * 64bit state; but it's unlikely to be worthwhile as 2^18-1 backends exceed
- * currently realistic configurations. Even if that limitation were removed,
- * we still could not a) exceed 2^23-1 because inval.c stores the ProcNumber
- * as a 3-byte signed integer, b) INT_MAX/4 because some places compute
- * 4*MaxBackends without any overflow check.  We check that the configured
- * number of backends does not exceed MAX_BACKENDS in InitializeMaxBackends().
+ * refcounts in buf_internals.h.  This limitation could be lifted, but it's
+ * unlikely to be worthwhile as 2^18-1 backends exceed currently realistic
+ * configurations. Even if that limitation were removed, we still could not a)
+ * exceed 2^23-1 because inval.c stores the ProcNumber as a 3-byte signed
+ * integer, b) INT_MAX/4 because some places compute 4*MaxBackends without any
+ * overflow check.  We check that the configured number of backends does not
+ * exceed MAX_BACKENDS in InitializeMaxBackends().
  */
 #define MAX_BACKENDS_BITS		18
 #define MAX_BACKENDS			((1U << MAX_BACKENDS_BITS)-1)
diff --git a/src/backend/storage/buffer/buf_init.c b/src/backend/storage/buffer/buf_init.c
index 9a312bcc7b3..7d894522526 100644
--- a/src/backend/storage/buffer/buf_init.c
+++ b/src/backend/storage/buffer/buf_init.c
@@ -121,7 +121,7 @@ BufferManagerShmemInit(void)
 
 			ClearBufferTag(&buf->tag);
 
-			pg_atomic_init_u32(&buf->state, 0);
+			pg_atomic_init_u64(&buf->state, 0);
 			buf->wait_backend_pgprocno = INVALID_PROC_NUMBER;
 
 			buf->buf_id = i;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index a036c2aa275..b0de8e45d4d 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -780,7 +780,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 {
 	BufferDesc *bufHdr;
 	BufferTag	tag;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(recent_buffer));
 
@@ -793,7 +793,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 		int			b = -recent_buffer - 1;
 
 		bufHdr = GetLocalBufferDescriptor(b);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		/* Is it still valid and holding the right tag? */
 		if ((buf_state & BM_VALID) && BufferTagsEqual(&tag, &bufHdr->tag))
@@ -1386,8 +1386,8 @@ StartReadBuffersImpl(ReadBuffersOperation *operation,
 				bufHdr = GetLocalBufferDescriptor(-buffers[i] - 1);
 			else
 				bufHdr = GetBufferDescriptor(buffers[i] - 1);
-			Assert(pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID);
-			found = pg_atomic_read_u32(&bufHdr->state) & BM_VALID;
+			Assert(pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID);
+			found = pg_atomic_read_u64(&bufHdr->state) & BM_VALID;
 		}
 		else
 		{
@@ -1613,10 +1613,10 @@ CheckReadBuffersOperation(ReadBuffersOperation *operation, bool is_complete)
 			GetBufferDescriptor(buffer - 1);
 
 		Assert(BufferGetBlockNumber(buffer) == operation->blocknum + i);
-		Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_TAG_VALID);
+		Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_TAG_VALID);
 
 		if (i < operation->nblocks_done)
-			Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_VALID);
+			Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_VALID);
 	}
 #endif
 }
@@ -2083,8 +2083,8 @@ BufferAlloc(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 	int			existing_buf_id;
 	Buffer		victim_buffer;
 	BufferDesc *victim_buf_hdr;
-	uint32		victim_buf_state;
-	uint32		set_bits = 0;
+	uint64		victim_buf_state;
+	uint64		set_bits = 0;
 
 	/* Make sure we will have room to remember the buffer pin */
 	ResourceOwnerEnlarge(CurrentResourceOwner);
@@ -2251,7 +2251,7 @@ InvalidateBuffer(BufferDesc *buf)
 	uint32		oldHash;		/* hash value for oldTag */
 	LWLock	   *oldPartitionLock;	/* buffer partition lock for it */
 	uint32		oldFlags;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/* Save the original buffer tag before dropping the spinlock */
 	oldTag = buf->tag;
@@ -2342,7 +2342,7 @@ retry:
 static bool
 InvalidateVictimBuffer(BufferDesc *buf_hdr)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	uint32		hash;
 	LWLock	   *partition_lock;
 	BufferTag	tag;
@@ -2402,10 +2402,10 @@ InvalidateVictimBuffer(BufferDesc *buf_hdr)
 
 	LWLockRelease(partition_lock);
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	Assert(!(buf_state & (BM_DIRTY | BM_VALID | BM_TAG_VALID)));
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
-	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u32(&buf_hdr->state)) > 0);
+	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u64(&buf_hdr->state)) > 0);
 
 	return true;
 }
@@ -2415,7 +2415,7 @@ GetVictimBuffer(BufferAccessStrategy strategy, IOContext io_context)
 {
 	BufferDesc *buf_hdr;
 	Buffer		buf;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		from_ring;
 
 	/*
@@ -2548,7 +2548,7 @@ again:
 
 	/* a final set of sanity checks */
 #ifdef USE_ASSERT_CHECKING
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) == 1);
 	Assert(!(buf_state & (BM_TAG_VALID | BM_VALID | BM_DIRTY)));
@@ -2839,13 +2839,13 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
 			 */
 			do
 			{
-				pg_atomic_fetch_and_u32(&existing_hdr->state, ~BM_VALID);
+				pg_atomic_fetch_and_u64(&existing_hdr->state, ~BM_VALID);
 			} while (!StartBufferIO(existing_hdr, true, false));
 		}
 		else
 		{
-			uint32		buf_state;
-			uint32		set_bits = 0;
+			uint64		buf_state;
+			uint64		set_bits = 0;
 
 			buf_state = LockBufHdr(victim_buf_hdr);
 
@@ -3021,7 +3021,7 @@ BufferIsDirty(Buffer buffer)
 		Assert(BufferIsLockedByMeInMode(buffer, BUFFER_LOCK_EXCLUSIVE));
 	}
 
-	return pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY;
+	return pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY;
 }
 
 /*
@@ -3037,8 +3037,8 @@ void
 MarkBufferDirty(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
-	uint32		old_buf_state;
+	uint64		buf_state;
+	uint64		old_buf_state;
 
 	if (!BufferIsValid(buffer))
 		elog(ERROR, "bad buffer ID: %d", buffer);
@@ -3058,7 +3058,7 @@ MarkBufferDirty(Buffer buffer)
 	 * NB: We have to wait for the buffer header spinlock to be not held, as
 	 * TerminateBufferIO() relies on the spinlock.
 	 */
-	old_buf_state = pg_atomic_read_u32(&bufHdr->state);
+	old_buf_state = pg_atomic_read_u64(&bufHdr->state);
 	for (;;)
 	{
 		if (old_buf_state & BM_LOCKED)
@@ -3069,7 +3069,7 @@ MarkBufferDirty(Buffer buffer)
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state |= BM_DIRTY | BM_JUST_DIRTIED;
 
-		if (pg_atomic_compare_exchange_u32(&bufHdr->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&bufHdr->state, &old_buf_state,
 										   buf_state))
 			break;
 	}
@@ -3173,10 +3173,10 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 
 	if (ref == NULL)
 	{
-		uint32		buf_state;
-		uint32		old_buf_state;
+		uint64		buf_state;
+		uint64		old_buf_state;
 
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			if (unlikely(skip_if_not_valid && !(old_buf_state & BM_VALID)))
@@ -3210,7 +3210,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 					buf_state += BUF_USAGECOUNT_ONE;
 			}
 
-			if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+			if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 											   buf_state))
 			{
 				result = (buf_state & BM_VALID) != 0;
@@ -3237,7 +3237,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 		 * that the buffer page is legitimately non-accessible here.  We
 		 * cannot meddle with that.
 		 */
-		result = (pg_atomic_read_u32(&buf->state) & BM_VALID) != 0;
+		result = (pg_atomic_read_u64(&buf->state) & BM_VALID) != 0;
 
 		Assert(ref->data.refcount > 0);
 		ref->data.refcount++;
@@ -3272,7 +3272,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 static void
 PinBuffer_Locked(BufferDesc *buf)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	/*
 	 * As explained, We don't expect any preexisting pins. That allows us to
@@ -3284,7 +3284,7 @@ PinBuffer_Locked(BufferDesc *buf)
 	 * Since we hold the buffer spinlock, we can update the buffer state and
 	 * release the lock in one operation.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 
 	UnlockBufHdrExt(buf, old_buf_state,
 					0, 0, 1);
@@ -3314,7 +3314,7 @@ WakePinCountWaiter(BufferDesc *buf)
 	 * BM_PIN_COUNT_WAITER if it stops waiting for a reason other than this
 	 * backend waking it up.
 	 */
-	uint32		buf_state = LockBufHdr(buf);
+	uint64		buf_state = LockBufHdr(buf);
 
 	if ((buf_state & BM_PIN_COUNT_WAITER) &&
 		BUF_STATE_GET_REFCOUNT(buf_state) == 1)
@@ -3361,7 +3361,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 	ref->data.refcount--;
 	if (ref->data.refcount == 0)
 	{
-		uint32		old_buf_state;
+		uint64		old_buf_state;
 
 		/*
 		 * Mark buffer non-accessible to Valgrind.
@@ -3379,7 +3379,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 		Assert(!LWLockHeldByMe(BufferDescriptorGetContentLock(buf)));
 
 		/* decrement the shared reference count */
-		old_buf_state = pg_atomic_fetch_sub_u32(&buf->state, BUF_REFCOUNT_ONE);
+		old_buf_state = pg_atomic_fetch_sub_u64(&buf->state, BUF_REFCOUNT_ONE);
 
 		/* Support LockBufferForCleanup() */
 		if (old_buf_state & BM_PIN_COUNT_WAITER)
@@ -3436,7 +3436,7 @@ TrackNewBufferPin(Buffer buf)
 static void
 BufferSync(int flags)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	int			buf_id;
 	int			num_to_scan;
 	int			num_spaces;
@@ -3446,7 +3446,7 @@ BufferSync(int flags)
 	Oid			last_tsid;
 	binaryheap *ts_heap;
 	int			i;
-	uint32		mask = BM_DIRTY;
+	uint64		mask = BM_DIRTY;
 	WritebackContext wb_context;
 
 	/*
@@ -3478,7 +3478,7 @@ BufferSync(int flags)
 	for (buf_id = 0; buf_id < NBuffers; buf_id++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
-		uint32		set_bits = 0;
+		uint64		set_bits = 0;
 
 		/*
 		 * Header spinlock is enough to examine BM_DIRTY, see comment in
@@ -3645,7 +3645,7 @@ BufferSync(int flags)
 		 * write the buffer though we didn't need to.  It doesn't seem worth
 		 * guarding against this, though.
 		 */
-		if (pg_atomic_read_u32(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
+		if (pg_atomic_read_u64(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
 		{
 			if (SyncOneBuffer(buf_id, false, &wb_context) & BUF_WRITTEN)
 			{
@@ -4015,7 +4015,7 @@ SyncOneBuffer(int buf_id, bool skip_recently_used, WritebackContext *wb_context)
 {
 	BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
 	int			result = 0;
-	uint32		buf_state;
+	uint64		buf_state;
 	BufferTag	tag;
 
 	/* Make sure we can handle the pin */
@@ -4264,7 +4264,7 @@ DebugPrintBufferRefcount(Buffer buffer)
 	int32		loccount;
 	char	   *result;
 	ProcNumber	backend;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
@@ -4281,9 +4281,9 @@ DebugPrintBufferRefcount(Buffer buffer)
 	}
 
 	/* theoretically we should lock the bufHdr here */
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
-	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
+	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%" PRIx64 ", refcount=%u %d)",
 					  buffer,
 					  relpathbackend(BufTagGetRelFileLocator(&buf->tag), backend,
 									 BufTagGetForkNum(&buf->tag)).str,
@@ -4383,7 +4383,7 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
 	instr_time	io_start;
 	Block		bufBlock;
 	char	   *bufToWrite;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * Try to start an I/O operation.  If StartBufferIO returns false, then
@@ -4581,7 +4581,7 @@ BufferIsPermanent(Buffer buffer)
 	 * not random garbage.
 	 */
 	bufHdr = GetBufferDescriptor(buffer - 1);
-	return (pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT) != 0;
+	return (pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT) != 0;
 }
 
 /*
@@ -5044,11 +5044,11 @@ FlushRelationBuffers(Relation rel)
 	{
 		for (i = 0; i < NLocBuffer; i++)
 		{
-			uint32		buf_state;
+			uint64		buf_state;
 
 			bufHdr = GetLocalBufferDescriptor(i);
 			if (BufTagMatchesRelFileLocator(&bufHdr->tag, &rel->rd_locator) &&
-				((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
+				((buf_state = pg_atomic_read_u64(&bufHdr->state)) &
 				 (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
 			{
 				ErrorContextCallback errcallback;
@@ -5084,7 +5084,7 @@ FlushRelationBuffers(Relation rel)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5156,7 +5156,7 @@ FlushRelationsAllBuffers(SMgrRelation *smgrs, int nrels)
 	{
 		SMgrSortArray *srelent = NULL;
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * As in DropRelationBuffers, an unlocked precheck should be safe and
@@ -5405,7 +5405,7 @@ FlushDatabaseBuffers(Oid dbid)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5553,13 +5553,13 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 	 * is only intended to be used in cases where failing to write out the
 	 * data would be harmless anyway, it doesn't really matter.
 	 */
-	if ((pg_atomic_read_u32(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
+	if ((pg_atomic_read_u64(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
 		(BM_DIRTY | BM_JUST_DIRTIED))
 	{
 		XLogRecPtr	lsn = InvalidXLogRecPtr;
 		bool		dirtied = false;
 		bool		delayChkptFlags = false;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * If we need to protect hint bit updates from torn writes, WAL-log a
@@ -5571,7 +5571,7 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 		 * when we call XLogInsert() since the value changes dynamically.
 		 */
 		if (XLogHintBitIsNeeded() &&
-			(pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT))
+			(pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT))
 		{
 			/*
 			 * If we must not write WAL, due to a relfilelocator-specific
@@ -5671,8 +5671,8 @@ UnlockBuffers(void)
 
 	if (buf)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		buf_state = LockBufHdr(buf);
 
@@ -5803,8 +5803,8 @@ LockBufferForCleanup(Buffer buffer)
 
 	for (;;)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -5952,7 +5952,7 @@ bool
 ConditionalLockBufferForCleanup(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state,
+	uint64		buf_state,
 				refcount;
 
 	Assert(BufferIsValid(buffer));
@@ -6010,7 +6010,7 @@ bool
 IsBufferCleanupOK(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 
@@ -6066,7 +6066,7 @@ WaitIO(BufferDesc *buf)
 	ConditionVariablePrepareToSleep(cv);
 	for (;;)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 		PgAioWaitRef iow;
 
 		/*
@@ -6140,7 +6140,7 @@ WaitIO(BufferDesc *buf)
 bool
 StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	ResourceOwnerEnlarge(CurrentResourceOwner);
 
@@ -6196,11 +6196,11 @@ StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
  * is being released)
  */
 void
-TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 				  bool forget_owner, bool release_aio)
 {
-	uint32		buf_state;
-	uint32		unset_flag_bits = 0;
+	uint64		buf_state;
+	uint64		unset_flag_bits = 0;
 	int			refcount_change = 0;
 
 	buf_state = LockBufHdr(buf);
@@ -6261,7 +6261,7 @@ static void
 AbortBufferIO(Buffer buffer)
 {
 	BufferDesc *buf_hdr = GetBufferDescriptor(buffer - 1);
-	uint32		buf_state;
+	uint64		buf_state;
 
 	buf_state = LockBufHdr(buf_hdr);
 	Assert(buf_state & (BM_IO_IN_PROGRESS | BM_TAG_VALID));
@@ -6355,10 +6355,10 @@ rlocator_comparator(const void *p1, const void *p2)
 /*
  * Lock buffer header - set BM_LOCKED in buffer state.
  */
-uint32
+uint64
 LockBufHdr(BufferDesc *desc)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	Assert(!BufferIsLocal(BufferDescriptorGetBuffer(desc)));
 
@@ -6369,7 +6369,7 @@ LockBufHdr(BufferDesc *desc)
 		 * the spin-delay infrastructure. The work necessary for that shows up
 		 * in profiles and is rarely necessary.
 		 */
-		old_buf_state = pg_atomic_fetch_or_u32(&desc->state, BM_LOCKED);
+		old_buf_state = pg_atomic_fetch_or_u64(&desc->state, BM_LOCKED);
 		if (likely(!(old_buf_state & BM_LOCKED)))
 			break;				/* got lock */
 
@@ -6382,7 +6382,7 @@ LockBufHdr(BufferDesc *desc)
 			while (old_buf_state & BM_LOCKED)
 			{
 				perform_spin_delay(&delayStatus);
-				old_buf_state = pg_atomic_read_u32(&desc->state);
+				old_buf_state = pg_atomic_read_u64(&desc->state);
 			}
 			finish_spin_delay(&delayStatus);
 		}
@@ -6403,20 +6403,20 @@ LockBufHdr(BufferDesc *desc)
  * Obviously the buffer could be locked by the time the value is returned, so
  * this is primarily useful in CAS style loops.
  */
-pg_noinline uint32
+pg_noinline uint64
 WaitBufHdrUnlocked(BufferDesc *buf)
 {
 	SpinDelayStatus delayStatus;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	init_local_spin_delay(&delayStatus);
 
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
 	while (buf_state & BM_LOCKED)
 	{
 		perform_spin_delay(&delayStatus);
-		buf_state = pg_atomic_read_u32(&buf->state);
+		buf_state = pg_atomic_read_u64(&buf->state);
 	}
 
 	finish_spin_delay(&delayStatus);
@@ -6704,12 +6704,12 @@ ResOwnerPrintBufferPin(Datum res)
 static bool
 EvictUnpinnedBufferInternal(BufferDesc *desc, bool *buffer_flushed)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result;
 
 	*buffer_flushed = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -6803,12 +6803,12 @@ EvictAllUnpinnedBuffers(int32 *buffers_evicted, int32 *buffers_flushed,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -6855,7 +6855,7 @@ EvictRelUnpinnedBuffers(Relation rel, int32 *buffers_evicted,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
@@ -6897,12 +6897,12 @@ static bool
 MarkDirtyUnpinnedBufferInternal(Buffer buf, BufferDesc *desc,
 								bool *buffer_already_dirty)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result = false;
 
 	*buffer_already_dirty = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -7000,7 +7000,7 @@ MarkDirtyRelUnpinnedBuffers(Relation rel,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
@@ -7054,12 +7054,12 @@ MarkDirtyAllUnpinnedBuffers(int32 *buffers_dirtied,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -7110,7 +7110,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		BufferDesc *buf_hdr = is_temp ?
 			GetLocalBufferDescriptor(-buffer - 1)
 			: GetBufferDescriptor(buffer - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * Check that all the buffers are actually ones that could conceivably
@@ -7128,7 +7128,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		}
 
 		if (is_temp)
-			buf_state = pg_atomic_read_u32(&buf_hdr->state);
+			buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		else
 			buf_state = LockBufHdr(buf_hdr);
 
@@ -7166,7 +7166,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		if (is_temp)
 		{
 			buf_state += BUF_REFCOUNT_ONE;
-			pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 		}
 		else
 			UnlockBufHdrExt(buf_hdr, buf_state, 0, 0, 1);
@@ -7352,13 +7352,13 @@ buffer_readv_complete_one(PgAioTargetData *td, uint8 buf_off, Buffer buffer,
 		: GetBufferDescriptor(buffer - 1);
 	BufferTag	tag = buf_hdr->tag;
 	char	   *bufdata = BufferGetBlock(buffer);
-	uint32		set_flag_bits;
+	uint64		set_flag_bits;
 	int			piv_flags;
 
 	/* check that the buffer is in the expected state for a read */
 #ifdef USE_ASSERT_CHECKING
 	{
-		uint32		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 		Assert(buf_state & BM_TAG_VALID);
 		Assert(!(buf_state & BM_VALID));
diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 9a93fb335fc..b7687836188 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -86,7 +86,7 @@ typedef struct BufferAccessStrategyData
 
 /* Prototypes for internal functions */
 static BufferDesc *GetBufferFromRing(BufferAccessStrategy strategy,
-									 uint32 *buf_state);
+									 uint64 *buf_state);
 static void AddBufferToRing(BufferAccessStrategy strategy,
 							BufferDesc *buf);
 
@@ -171,7 +171,7 @@ ClockSweepTick(void)
  *	before returning.
  */
 BufferDesc *
-StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_ring)
+StrategyGetBuffer(BufferAccessStrategy strategy, uint64 *buf_state, bool *from_ring)
 {
 	BufferDesc *buf;
 	int			bgwprocno;
@@ -230,8 +230,8 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 	trycounter = NBuffers;
 	for (;;)
 	{
-		uint32		old_buf_state;
-		uint32		local_buf_state;
+		uint64		old_buf_state;
+		uint64		local_buf_state;
 
 		buf = GetBufferDescriptor(ClockSweepTick());
 
@@ -239,7 +239,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 		 * Check whether the buffer can be used and pin it if so. Do this
 		 * using a CAS loop, to avoid having to lock the buffer header.
 		 */
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			local_buf_state = old_buf_state;
@@ -277,7 +277,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 			{
 				local_buf_state -= BUF_USAGECOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					trycounter = NBuffers;
@@ -289,7 +289,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 				/* pin the buffer if the CAS succeeds */
 				local_buf_state += BUF_REFCOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					/* Found a usable buffer */
@@ -655,12 +655,12 @@ FreeAccessStrategy(BufferAccessStrategy strategy)
  * returning.
  */
 static BufferDesc *
-GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
+GetBufferFromRing(BufferAccessStrategy strategy, uint64 *buf_state)
 {
 	BufferDesc *buf;
 	Buffer		bufnum;
-	uint32		old_buf_state;
-	uint32		local_buf_state;	/* to avoid repeated (de-)referencing */
+	uint64		old_buf_state;
+	uint64		local_buf_state;	/* to avoid repeated (de-)referencing */
 
 
 	/* Advance to next ring slot */
@@ -682,7 +682,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 	 * Check whether the buffer can be used and pin it if so. Do this using a
 	 * CAS loop, to avoid having to lock the buffer header.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 	for (;;)
 	{
 		local_buf_state = old_buf_state;
@@ -710,7 +710,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 		/* pin the buffer if the CAS succeeds */
 		local_buf_state += BUF_REFCOUNT_ONE;
 
-		if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 										   local_buf_state))
 		{
 			*buf_state = local_buf_state;
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index f6e2b1aa288..04a540379a2 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -148,7 +148,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	}
 	else
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		victim_buffer = GetLocalVictimBuffer();
 		bufid = -victim_buffer - 1;
@@ -165,10 +165,10 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		 */
 		bufHdr->tag = newTag;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		buf_state &= ~(BUF_FLAG_MASK | BUF_USAGECOUNT_MASK);
 		buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 		*foundPtr = false;
 	}
@@ -245,12 +245,12 @@ GetLocalVictimBuffer(void)
 
 		if (LocalRefCount[victim_bufid] == 0)
 		{
-			uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 			if (BUF_STATE_GET_USAGECOUNT(buf_state) > 0)
 			{
 				buf_state -= BUF_USAGECOUNT_ONE;
-				pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+				pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 				trycounter = NLocBuffer;
 			}
 			else if (BUF_STATE_GET_REFCOUNT(buf_state) > 0)
@@ -286,13 +286,13 @@ GetLocalVictimBuffer(void)
 	 * this buffer is not referenced but it might still be dirty. if that's
 	 * the case, write it out before reusing it!
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY)
 		FlushLocalBuffer(bufHdr, NULL);
 
 	/*
 	 * Remove the victim buffer from the hashtable and mark as invalid.
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID)
 	{
 		InvalidateLocalBuffer(bufHdr, false);
 
@@ -417,7 +417,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 		if (found)
 		{
 			BufferDesc *existing_hdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			UnpinLocalBuffer(BufferDescriptorGetBuffer(victim_buf_hdr));
 
@@ -428,18 +428,18 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 			/*
 			 * Clear the BM_VALID bit, do StartLocalBufferIO() and proceed.
 			 */
-			buf_state = pg_atomic_read_u32(&existing_hdr->state);
+			buf_state = pg_atomic_read_u64(&existing_hdr->state);
 			Assert(buf_state & BM_TAG_VALID);
 			Assert(!(buf_state & BM_DIRTY));
 			buf_state &= ~BM_VALID;
-			pg_atomic_unlocked_write_u32(&existing_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&existing_hdr->state, buf_state);
 
 			/* no need to loop for local buffers */
 			StartLocalBufferIO(existing_hdr, true, false);
 		}
 		else
 		{
-			uint32		buf_state = pg_atomic_read_u32(&victim_buf_hdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&victim_buf_hdr->state);
 
 			Assert(!(buf_state & (BM_VALID | BM_TAG_VALID | BM_DIRTY | BM_JUST_DIRTIED)));
 
@@ -447,7 +447,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 
 			buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
 
-			pg_atomic_unlocked_write_u32(&victim_buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&victim_buf_hdr->state, buf_state);
 
 			hresult->id = victim_buf_id;
 
@@ -467,13 +467,13 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 	{
 		Buffer		buf = buffers[i];
 		BufferDesc *buf_hdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		buf_state |= BM_VALID;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 
 	*extended_by = extend_by;
@@ -492,7 +492,7 @@ MarkLocalBufferDirty(Buffer buffer)
 {
 	int			bufid;
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsLocal(buffer));
 
@@ -506,14 +506,14 @@ MarkLocalBufferDirty(Buffer buffer)
 
 	bufHdr = GetLocalBufferDescriptor(bufid);
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	if (!(buf_state & BM_DIRTY))
 		pgBufferUsage.local_blks_dirtied++;
 
 	buf_state |= BM_DIRTY;
 
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -522,7 +522,7 @@ MarkLocalBufferDirty(Buffer buffer)
 bool
 StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * With AIO the buffer could have IO in progress, e.g. when there are two
@@ -542,7 +542,7 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 	/* Once we get here, there is definitely no I/O active on this buffer */
 
 	/* Check if someone else already did the I/O */
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 	if (forInput ? (buf_state & BM_VALID) : !(buf_state & BM_DIRTY))
 	{
 		return false;
@@ -559,11 +559,11 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
  * Like TerminateBufferIO, but for local buffers
  */
 void
-TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bits,
+TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint64 set_flag_bits,
 					   bool release_aio)
 {
 	/* Only need to adjust flags */
-	uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+	uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/* BM_IO_IN_PROGRESS isn't currently used for local buffers */
 
@@ -582,7 +582,7 @@ TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bit
 	}
 
 	buf_state |= set_flag_bits;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 	/* local buffers don't track IO using resowners */
 
@@ -606,7 +606,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 {
 	Buffer		buffer = BufferDescriptorGetBuffer(bufHdr);
 	int			bufid = -buffer - 1;
-	uint32		buf_state;
+	uint64		buf_state;
 	LocalBufferLookupEnt *hresult;
 
 	/*
@@ -622,7 +622,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 		Assert(!pgaio_wref_valid(&bufHdr->io_wref));
 	}
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/*
 	 * We need to test not just LocalRefCount[bufid] but also the BufferDesc
@@ -647,7 +647,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 	ClearBufferTag(&bufHdr->tag);
 	buf_state &= ~BUF_FLAG_MASK;
 	buf_state &= ~BUF_USAGECOUNT_MASK;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -671,9 +671,9 @@ DropRelationLocalBuffers(RelFileLocator rlocator, ForkNumber *forkNum,
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (!(buf_state & BM_TAG_VALID) ||
 			!BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -706,9 +706,9 @@ DropRelationAllLocalBuffers(RelFileLocator rlocator)
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if ((buf_state & BM_TAG_VALID) &&
 			BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -804,11 +804,11 @@ InitLocalBuffers(void)
 bool
 PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	Buffer		buffer = BufferDescriptorGetBuffer(buf_hdr);
 	int			bufid = -buffer - 1;
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	if (LocalRefCount[bufid] == 0)
 	{
@@ -819,7 +819,7 @@ PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 		{
 			buf_state += BUF_USAGECOUNT_ONE;
 		}
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/*
 		 * See comment in PinBuffer().
@@ -856,14 +856,14 @@ UnpinLocalBufferNoOwner(Buffer buffer)
 	if (--LocalRefCount[buffid] == 0)
 	{
 		BufferDesc *buf_hdr = GetLocalBufferDescriptor(buffid);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		NLocalPinnedBuffers--;
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state -= BUF_REFCOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/* see comment in UnpinBufferNoOwner */
 		VALGRIND_MAKE_MEM_NOACCESS(LocalBufHdrGetBlock(buf_hdr), BLCKSZ);
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index 0c58e4b265c..529803346ce 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -199,7 +199,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 		for (i = 0; i < NBuffers; i++)
 		{
 			BufferDesc *bufHdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			CHECK_FOR_INTERRUPTS();
 
@@ -615,7 +615,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		CHECK_FOR_INTERRUPTS();
 
@@ -626,7 +626,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 		 * noticeably increase the cost of the function.
 		 */
 		bufHdr = GetBufferDescriptor(i);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (buf_state & BM_VALID)
 		{
@@ -676,7 +676,7 @@ pg_buffercache_usage_counts(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		int			usage_count;
 
 		CHECK_FOR_INTERRUPTS();
diff --git a/src/test/modules/test_aio/test_aio.c b/src/test/modules/test_aio/test_aio.c
index e046b08f3d5..b1aa8af9ec0 100644
--- a/src/test/modules/test_aio/test_aio.c
+++ b/src/test/modules/test_aio/test_aio.c
@@ -308,9 +308,9 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 {
 	Buffer		buf;
 	BufferDesc *buf_hdr;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		was_pinned = false;
-	uint32		unset_bits = 0;
+	uint64		unset_bits = 0;
 
 	/* place buffer in shared buffers without erroring out */
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_ZERO_AND_LOCK, NULL);
@@ -319,7 +319,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	}
 	else
 	{
@@ -340,7 +340,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_state &= ~unset_bits;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 	else
 	{
@@ -489,7 +489,7 @@ invalidate_rel_block(PG_FUNCTION_ARGS)
 
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-			if (pg_atomic_read_u32(&buf_hdr->state) & BM_DIRTY)
+			if (pg_atomic_read_u64(&buf_hdr->state) & BM_DIRTY)
 			{
 				if (BufferIsLocal(buf))
 					FlushLocalBuffer(buf_hdr, NULL);
@@ -572,7 +572,7 @@ buffer_call_terminate_io(PG_FUNCTION_ARGS)
 	bool		io_error = PG_GETARG_BOOL(3);
 	bool		release_aio = PG_GETARG_BOOL(4);
 	bool		clear_dirty = false;
-	uint32		set_flag_bits = 0;
+	uint64		set_flag_bits = 0;
 
 	if (io_error)
 		set_flag_bits |= BM_IO_ERROR;
-- 
2.48.1.76.g4e746b1a31.dirty


--rkiyqpij3ajqn7ww
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v9-0007-bufmgr-Implement-buffer-content-locks-independent.patch"



^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* [PATCH v10 3/8] bufmgr: Change BufferDesc.state to be a 64-bit atomic
@ 2026-01-07 22:26  Andres Freund <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Andres Freund @ 2026-01-07 22:26 UTC (permalink / raw)

This is motivated by wanting to merge buffer content locks into
BufferDesc.state in a future commit, rather than having a separate lwlock (see
commit c75ebc657ff for more details). As this change is rather mechanical, it
seems to make sense to split it out into a separate commit, for easier review.

Reviewed-by: Melanie Plageman <[email protected]>
Discussion: https://postgr.es/m/fvfmkr5kk4nyex56ejgxj3uzi63isfxovp2biecb4bspbjrze7@az2pljabhnff
---
 src/include/storage/buf_internals.h           |  51 +++---
 src/include/storage/procnumber.h              |  14 +-
 src/backend/storage/buffer/buf_init.c         |   2 +-
 src/backend/storage/buffer/bufmgr.c           | 170 +++++++++---------
 src/backend/storage/buffer/freelist.c         |  24 +--
 src/backend/storage/buffer/localbuf.c         |  72 ++++----
 contrib/pg_buffercache/pg_buffercache_pages.c |   8 +-
 src/test/modules/test_aio/test_aio.c          |  12 +-
 8 files changed, 178 insertions(+), 175 deletions(-)

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index 2f607ea2ac5..a4d36e9ca01 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -30,7 +30,7 @@
 #include "utils/resowner.h"
 
 /*
- * Buffer state is a single 32-bit variable where following data is combined.
+ * Buffer state is a single 64-bit variable where following data is combined.
  *
  * State of the buffer itself (in order):
  * - 18 bits refcount
@@ -40,6 +40,9 @@
  * Combining these values allows to perform some operations without locking
  * the buffer header, by modifying them together with a CAS loop.
  *
+ * NB: A future commit will use a significant portion of the remaining bits to
+ * implement buffer locking as part of the state variable.
+ *
  * The definition of buffer state components is below.
  */
 #define BUF_REFCOUNT_BITS 18
@@ -52,27 +55,27 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
 /* refcount related definitions */
 #define BUF_REFCOUNT_ONE 1
 #define BUF_REFCOUNT_MASK \
-	((1U << BUF_REFCOUNT_BITS) - 1)
+	((UINT64CONST(1) << BUF_REFCOUNT_BITS) - 1)
 
 /* usage count related definitions */
 #define BUF_USAGECOUNT_SHIFT \
 	BUF_REFCOUNT_BITS
 #define BUF_USAGECOUNT_MASK \
-	(((1U << BUF_USAGECOUNT_BITS) - 1) << (BUF_USAGECOUNT_SHIFT))
+	(((UINT64CONST(1) << BUF_USAGECOUNT_BITS) - 1) << (BUF_USAGECOUNT_SHIFT))
 #define BUF_USAGECOUNT_ONE \
-	(1U << BUF_REFCOUNT_BITS)
+	(UINT64CONST(1) << BUF_REFCOUNT_BITS)
 
 /* flags related definitions */
 #define BUF_FLAG_SHIFT \
 	(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS)
 #define BUF_FLAG_MASK \
-	(((1U << BUF_FLAG_BITS) - 1) << BUF_FLAG_SHIFT)
+	(((UINT64CONST(1) << BUF_FLAG_BITS) - 1) << BUF_FLAG_SHIFT)
 
 /* Get refcount and usagecount from buffer state */
 #define BUF_STATE_GET_REFCOUNT(state) \
-	((state) & BUF_REFCOUNT_MASK)
+	((uint32)((state) & BUF_REFCOUNT_MASK))
 #define BUF_STATE_GET_USAGECOUNT(state) \
-	(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT)
+	((uint32)(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT))
 
 /*
  * Flags for buffer descriptors
@@ -82,7 +85,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 
 #define BUF_DEFINE_FLAG(flagno)	\
-	(1U << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + (flagno)))
+	(UINT64CONST(1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + (flagno)))
 
 /* buffer header is locked */
 #define BM_LOCKED					BUF_DEFINE_FLAG( 0)
@@ -115,7 +118,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 #define BM_MAX_USAGE_COUNT	5
 
-StaticAssertDecl(BM_MAX_USAGE_COUNT < (1 << BUF_USAGECOUNT_BITS),
+StaticAssertDecl(BM_MAX_USAGE_COUNT < (UINT64CONST(1) << BUF_USAGECOUNT_BITS),
 				 "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
 StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
 				 "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
@@ -280,8 +283,8 @@ BufMappingPartitionLockByIndex(uint32 index)
  * We use this same struct for local buffer headers, but the locks are not
  * used and not all of the flag bits are useful either. To avoid unnecessary
  * overhead, manipulations of the state field should be done without actual
- * atomic operations (i.e. only pg_atomic_read_u32() and
- * pg_atomic_unlocked_write_u32()).
+ * atomic operations (i.e. only pg_atomic_read_u64() and
+ * pg_atomic_unlocked_write_u64()).
  *
  * Be careful to avoid increasing the size of the struct when adding or
  * reordering members.  Keeping it below 64 bytes (the most common CPU
@@ -309,7 +312,7 @@ typedef struct BufferDesc
 	 * State of the buffer, containing flags, refcount and usagecount. See
 	 * BUF_* and BM_* defines at the top of this file.
 	 */
-	pg_atomic_uint32 state;
+	pg_atomic_uint64 state;
 
 	/*
 	 * Backend of pin-count waiter. The buffer header spinlock needs to be
@@ -415,7 +418,7 @@ BufferDescriptorGetContentLock(const BufferDesc *bdesc)
  * Functions for acquiring/releasing a shared buffer header's spinlock.  Do
  * not apply these to local buffers!
  */
-extern uint32 LockBufHdr(BufferDesc *desc);
+extern uint64 LockBufHdr(BufferDesc *desc);
 
 /*
  * Unlock the buffer header.
@@ -426,9 +429,9 @@ extern uint32 LockBufHdr(BufferDesc *desc);
 static inline void
 UnlockBufHdr(BufferDesc *desc)
 {
-	Assert(pg_atomic_read_u32(&desc->state) & BM_LOCKED);
+	Assert(pg_atomic_read_u64(&desc->state) & BM_LOCKED);
 
-	pg_atomic_fetch_sub_u32(&desc->state, BM_LOCKED);
+	pg_atomic_fetch_sub_u64(&desc->state, BM_LOCKED);
 }
 
 /*
@@ -439,14 +442,14 @@ UnlockBufHdr(BufferDesc *desc)
  * Note that this approach would not work for usagecount, since we need to cap
  * the usagecount at BM_MAX_USAGE_COUNT.
  */
-static inline uint32
-UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
-				uint32 set_bits, uint32 unset_bits,
+static inline uint64
+UnlockBufHdrExt(BufferDesc *desc, uint64 old_buf_state,
+				uint64 set_bits, uint64 unset_bits,
 				int refcount_change)
 {
 	for (;;)
 	{
-		uint32		buf_state = old_buf_state;
+		uint64		buf_state = old_buf_state;
 
 		Assert(buf_state & BM_LOCKED);
 
@@ -457,7 +460,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 		if (refcount_change != 0)
 			buf_state += BUF_REFCOUNT_ONE * refcount_change;
 
-		if (pg_atomic_compare_exchange_u32(&desc->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&desc->state, &old_buf_state,
 										   buf_state))
 		{
 			return old_buf_state;
@@ -465,7 +468,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 	}
 }
 
-extern uint32 WaitBufHdrUnlocked(BufferDesc *buf);
+extern uint64 WaitBufHdrUnlocked(BufferDesc *buf);
 
 /* in bufmgr.c */
 
@@ -525,14 +528,14 @@ extern void TrackNewBufferPin(Buffer buf);
 
 /* solely to make it easier to write tests */
 extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
-extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 							  bool forget_owner, bool release_aio);
 
 
 /* freelist.c */
 extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
 extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
-									 uint32 *buf_state, bool *from_ring);
+									 uint64 *buf_state, bool *from_ring);
 extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
 								 BufferDesc *buf, bool from_ring);
 
@@ -568,7 +571,7 @@ extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
 										  uint32 *extended_by);
 extern void MarkLocalBufferDirty(Buffer buffer);
 extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
-								   uint32 set_flag_bits, bool release_aio);
+								   uint64 set_flag_bits, bool release_aio);
 extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
 extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
 extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
diff --git a/src/include/storage/procnumber.h b/src/include/storage/procnumber.h
index 30c360ad350..bd9cb3891cc 100644
--- a/src/include/storage/procnumber.h
+++ b/src/include/storage/procnumber.h
@@ -27,13 +27,13 @@ typedef int ProcNumber;
 
 /*
  * Note: MAX_BACKENDS_BITS is 18 as that is the space available for buffer
- * refcounts in buf_internals.h.  This limitation could be lifted by using a
- * 64bit state; but it's unlikely to be worthwhile as 2^18-1 backends exceed
- * currently realistic configurations. Even if that limitation were removed,
- * we still could not a) exceed 2^23-1 because inval.c stores the ProcNumber
- * as a 3-byte signed integer, b) INT_MAX/4 because some places compute
- * 4*MaxBackends without any overflow check.  We check that the configured
- * number of backends does not exceed MAX_BACKENDS in InitializeMaxBackends().
+ * refcounts in buf_internals.h.  This limitation could be lifted, but it's
+ * unlikely to be worthwhile as 2^18-1 backends exceed currently realistic
+ * configurations. Even if that limitation were removed, we still could not a)
+ * exceed 2^23-1 because inval.c stores the ProcNumber as a 3-byte signed
+ * integer, b) INT_MAX/4 because some places compute 4*MaxBackends without any
+ * overflow check.  We check that the configured number of backends does not
+ * exceed MAX_BACKENDS in InitializeMaxBackends().
  */
 #define MAX_BACKENDS_BITS		18
 #define MAX_BACKENDS			((1U << MAX_BACKENDS_BITS)-1)
diff --git a/src/backend/storage/buffer/buf_init.c b/src/backend/storage/buffer/buf_init.c
index 9a312bcc7b3..7d894522526 100644
--- a/src/backend/storage/buffer/buf_init.c
+++ b/src/backend/storage/buffer/buf_init.c
@@ -121,7 +121,7 @@ BufferManagerShmemInit(void)
 
 			ClearBufferTag(&buf->tag);
 
-			pg_atomic_init_u32(&buf->state, 0);
+			pg_atomic_init_u64(&buf->state, 0);
 			buf->wait_backend_pgprocno = INVALID_PROC_NUMBER;
 
 			buf->buf_id = i;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index a036c2aa275..b0de8e45d4d 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -780,7 +780,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 {
 	BufferDesc *bufHdr;
 	BufferTag	tag;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(recent_buffer));
 
@@ -793,7 +793,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 		int			b = -recent_buffer - 1;
 
 		bufHdr = GetLocalBufferDescriptor(b);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		/* Is it still valid and holding the right tag? */
 		if ((buf_state & BM_VALID) && BufferTagsEqual(&tag, &bufHdr->tag))
@@ -1386,8 +1386,8 @@ StartReadBuffersImpl(ReadBuffersOperation *operation,
 				bufHdr = GetLocalBufferDescriptor(-buffers[i] - 1);
 			else
 				bufHdr = GetBufferDescriptor(buffers[i] - 1);
-			Assert(pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID);
-			found = pg_atomic_read_u32(&bufHdr->state) & BM_VALID;
+			Assert(pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID);
+			found = pg_atomic_read_u64(&bufHdr->state) & BM_VALID;
 		}
 		else
 		{
@@ -1613,10 +1613,10 @@ CheckReadBuffersOperation(ReadBuffersOperation *operation, bool is_complete)
 			GetBufferDescriptor(buffer - 1);
 
 		Assert(BufferGetBlockNumber(buffer) == operation->blocknum + i);
-		Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_TAG_VALID);
+		Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_TAG_VALID);
 
 		if (i < operation->nblocks_done)
-			Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_VALID);
+			Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_VALID);
 	}
 #endif
 }
@@ -2083,8 +2083,8 @@ BufferAlloc(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 	int			existing_buf_id;
 	Buffer		victim_buffer;
 	BufferDesc *victim_buf_hdr;
-	uint32		victim_buf_state;
-	uint32		set_bits = 0;
+	uint64		victim_buf_state;
+	uint64		set_bits = 0;
 
 	/* Make sure we will have room to remember the buffer pin */
 	ResourceOwnerEnlarge(CurrentResourceOwner);
@@ -2251,7 +2251,7 @@ InvalidateBuffer(BufferDesc *buf)
 	uint32		oldHash;		/* hash value for oldTag */
 	LWLock	   *oldPartitionLock;	/* buffer partition lock for it */
 	uint32		oldFlags;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/* Save the original buffer tag before dropping the spinlock */
 	oldTag = buf->tag;
@@ -2342,7 +2342,7 @@ retry:
 static bool
 InvalidateVictimBuffer(BufferDesc *buf_hdr)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	uint32		hash;
 	LWLock	   *partition_lock;
 	BufferTag	tag;
@@ -2402,10 +2402,10 @@ InvalidateVictimBuffer(BufferDesc *buf_hdr)
 
 	LWLockRelease(partition_lock);
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	Assert(!(buf_state & (BM_DIRTY | BM_VALID | BM_TAG_VALID)));
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
-	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u32(&buf_hdr->state)) > 0);
+	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u64(&buf_hdr->state)) > 0);
 
 	return true;
 }
@@ -2415,7 +2415,7 @@ GetVictimBuffer(BufferAccessStrategy strategy, IOContext io_context)
 {
 	BufferDesc *buf_hdr;
 	Buffer		buf;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		from_ring;
 
 	/*
@@ -2548,7 +2548,7 @@ again:
 
 	/* a final set of sanity checks */
 #ifdef USE_ASSERT_CHECKING
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) == 1);
 	Assert(!(buf_state & (BM_TAG_VALID | BM_VALID | BM_DIRTY)));
@@ -2839,13 +2839,13 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
 			 */
 			do
 			{
-				pg_atomic_fetch_and_u32(&existing_hdr->state, ~BM_VALID);
+				pg_atomic_fetch_and_u64(&existing_hdr->state, ~BM_VALID);
 			} while (!StartBufferIO(existing_hdr, true, false));
 		}
 		else
 		{
-			uint32		buf_state;
-			uint32		set_bits = 0;
+			uint64		buf_state;
+			uint64		set_bits = 0;
 
 			buf_state = LockBufHdr(victim_buf_hdr);
 
@@ -3021,7 +3021,7 @@ BufferIsDirty(Buffer buffer)
 		Assert(BufferIsLockedByMeInMode(buffer, BUFFER_LOCK_EXCLUSIVE));
 	}
 
-	return pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY;
+	return pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY;
 }
 
 /*
@@ -3037,8 +3037,8 @@ void
 MarkBufferDirty(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
-	uint32		old_buf_state;
+	uint64		buf_state;
+	uint64		old_buf_state;
 
 	if (!BufferIsValid(buffer))
 		elog(ERROR, "bad buffer ID: %d", buffer);
@@ -3058,7 +3058,7 @@ MarkBufferDirty(Buffer buffer)
 	 * NB: We have to wait for the buffer header spinlock to be not held, as
 	 * TerminateBufferIO() relies on the spinlock.
 	 */
-	old_buf_state = pg_atomic_read_u32(&bufHdr->state);
+	old_buf_state = pg_atomic_read_u64(&bufHdr->state);
 	for (;;)
 	{
 		if (old_buf_state & BM_LOCKED)
@@ -3069,7 +3069,7 @@ MarkBufferDirty(Buffer buffer)
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state |= BM_DIRTY | BM_JUST_DIRTIED;
 
-		if (pg_atomic_compare_exchange_u32(&bufHdr->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&bufHdr->state, &old_buf_state,
 										   buf_state))
 			break;
 	}
@@ -3173,10 +3173,10 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 
 	if (ref == NULL)
 	{
-		uint32		buf_state;
-		uint32		old_buf_state;
+		uint64		buf_state;
+		uint64		old_buf_state;
 
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			if (unlikely(skip_if_not_valid && !(old_buf_state & BM_VALID)))
@@ -3210,7 +3210,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 					buf_state += BUF_USAGECOUNT_ONE;
 			}
 
-			if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+			if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 											   buf_state))
 			{
 				result = (buf_state & BM_VALID) != 0;
@@ -3237,7 +3237,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 		 * that the buffer page is legitimately non-accessible here.  We
 		 * cannot meddle with that.
 		 */
-		result = (pg_atomic_read_u32(&buf->state) & BM_VALID) != 0;
+		result = (pg_atomic_read_u64(&buf->state) & BM_VALID) != 0;
 
 		Assert(ref->data.refcount > 0);
 		ref->data.refcount++;
@@ -3272,7 +3272,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 static void
 PinBuffer_Locked(BufferDesc *buf)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	/*
 	 * As explained, We don't expect any preexisting pins. That allows us to
@@ -3284,7 +3284,7 @@ PinBuffer_Locked(BufferDesc *buf)
 	 * Since we hold the buffer spinlock, we can update the buffer state and
 	 * release the lock in one operation.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 
 	UnlockBufHdrExt(buf, old_buf_state,
 					0, 0, 1);
@@ -3314,7 +3314,7 @@ WakePinCountWaiter(BufferDesc *buf)
 	 * BM_PIN_COUNT_WAITER if it stops waiting for a reason other than this
 	 * backend waking it up.
 	 */
-	uint32		buf_state = LockBufHdr(buf);
+	uint64		buf_state = LockBufHdr(buf);
 
 	if ((buf_state & BM_PIN_COUNT_WAITER) &&
 		BUF_STATE_GET_REFCOUNT(buf_state) == 1)
@@ -3361,7 +3361,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 	ref->data.refcount--;
 	if (ref->data.refcount == 0)
 	{
-		uint32		old_buf_state;
+		uint64		old_buf_state;
 
 		/*
 		 * Mark buffer non-accessible to Valgrind.
@@ -3379,7 +3379,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 		Assert(!LWLockHeldByMe(BufferDescriptorGetContentLock(buf)));
 
 		/* decrement the shared reference count */
-		old_buf_state = pg_atomic_fetch_sub_u32(&buf->state, BUF_REFCOUNT_ONE);
+		old_buf_state = pg_atomic_fetch_sub_u64(&buf->state, BUF_REFCOUNT_ONE);
 
 		/* Support LockBufferForCleanup() */
 		if (old_buf_state & BM_PIN_COUNT_WAITER)
@@ -3436,7 +3436,7 @@ TrackNewBufferPin(Buffer buf)
 static void
 BufferSync(int flags)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	int			buf_id;
 	int			num_to_scan;
 	int			num_spaces;
@@ -3446,7 +3446,7 @@ BufferSync(int flags)
 	Oid			last_tsid;
 	binaryheap *ts_heap;
 	int			i;
-	uint32		mask = BM_DIRTY;
+	uint64		mask = BM_DIRTY;
 	WritebackContext wb_context;
 
 	/*
@@ -3478,7 +3478,7 @@ BufferSync(int flags)
 	for (buf_id = 0; buf_id < NBuffers; buf_id++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
-		uint32		set_bits = 0;
+		uint64		set_bits = 0;
 
 		/*
 		 * Header spinlock is enough to examine BM_DIRTY, see comment in
@@ -3645,7 +3645,7 @@ BufferSync(int flags)
 		 * write the buffer though we didn't need to.  It doesn't seem worth
 		 * guarding against this, though.
 		 */
-		if (pg_atomic_read_u32(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
+		if (pg_atomic_read_u64(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
 		{
 			if (SyncOneBuffer(buf_id, false, &wb_context) & BUF_WRITTEN)
 			{
@@ -4015,7 +4015,7 @@ SyncOneBuffer(int buf_id, bool skip_recently_used, WritebackContext *wb_context)
 {
 	BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
 	int			result = 0;
-	uint32		buf_state;
+	uint64		buf_state;
 	BufferTag	tag;
 
 	/* Make sure we can handle the pin */
@@ -4264,7 +4264,7 @@ DebugPrintBufferRefcount(Buffer buffer)
 	int32		loccount;
 	char	   *result;
 	ProcNumber	backend;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
@@ -4281,9 +4281,9 @@ DebugPrintBufferRefcount(Buffer buffer)
 	}
 
 	/* theoretically we should lock the bufHdr here */
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
-	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
+	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%" PRIx64 ", refcount=%u %d)",
 					  buffer,
 					  relpathbackend(BufTagGetRelFileLocator(&buf->tag), backend,
 									 BufTagGetForkNum(&buf->tag)).str,
@@ -4383,7 +4383,7 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
 	instr_time	io_start;
 	Block		bufBlock;
 	char	   *bufToWrite;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * Try to start an I/O operation.  If StartBufferIO returns false, then
@@ -4581,7 +4581,7 @@ BufferIsPermanent(Buffer buffer)
 	 * not random garbage.
 	 */
 	bufHdr = GetBufferDescriptor(buffer - 1);
-	return (pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT) != 0;
+	return (pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT) != 0;
 }
 
 /*
@@ -5044,11 +5044,11 @@ FlushRelationBuffers(Relation rel)
 	{
 		for (i = 0; i < NLocBuffer; i++)
 		{
-			uint32		buf_state;
+			uint64		buf_state;
 
 			bufHdr = GetLocalBufferDescriptor(i);
 			if (BufTagMatchesRelFileLocator(&bufHdr->tag, &rel->rd_locator) &&
-				((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
+				((buf_state = pg_atomic_read_u64(&bufHdr->state)) &
 				 (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
 			{
 				ErrorContextCallback errcallback;
@@ -5084,7 +5084,7 @@ FlushRelationBuffers(Relation rel)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5156,7 +5156,7 @@ FlushRelationsAllBuffers(SMgrRelation *smgrs, int nrels)
 	{
 		SMgrSortArray *srelent = NULL;
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * As in DropRelationBuffers, an unlocked precheck should be safe and
@@ -5405,7 +5405,7 @@ FlushDatabaseBuffers(Oid dbid)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5553,13 +5553,13 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 	 * is only intended to be used in cases where failing to write out the
 	 * data would be harmless anyway, it doesn't really matter.
 	 */
-	if ((pg_atomic_read_u32(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
+	if ((pg_atomic_read_u64(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
 		(BM_DIRTY | BM_JUST_DIRTIED))
 	{
 		XLogRecPtr	lsn = InvalidXLogRecPtr;
 		bool		dirtied = false;
 		bool		delayChkptFlags = false;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * If we need to protect hint bit updates from torn writes, WAL-log a
@@ -5571,7 +5571,7 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 		 * when we call XLogInsert() since the value changes dynamically.
 		 */
 		if (XLogHintBitIsNeeded() &&
-			(pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT))
+			(pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT))
 		{
 			/*
 			 * If we must not write WAL, due to a relfilelocator-specific
@@ -5671,8 +5671,8 @@ UnlockBuffers(void)
 
 	if (buf)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		buf_state = LockBufHdr(buf);
 
@@ -5803,8 +5803,8 @@ LockBufferForCleanup(Buffer buffer)
 
 	for (;;)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -5952,7 +5952,7 @@ bool
 ConditionalLockBufferForCleanup(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state,
+	uint64		buf_state,
 				refcount;
 
 	Assert(BufferIsValid(buffer));
@@ -6010,7 +6010,7 @@ bool
 IsBufferCleanupOK(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 
@@ -6066,7 +6066,7 @@ WaitIO(BufferDesc *buf)
 	ConditionVariablePrepareToSleep(cv);
 	for (;;)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 		PgAioWaitRef iow;
 
 		/*
@@ -6140,7 +6140,7 @@ WaitIO(BufferDesc *buf)
 bool
 StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	ResourceOwnerEnlarge(CurrentResourceOwner);
 
@@ -6196,11 +6196,11 @@ StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
  * is being released)
  */
 void
-TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 				  bool forget_owner, bool release_aio)
 {
-	uint32		buf_state;
-	uint32		unset_flag_bits = 0;
+	uint64		buf_state;
+	uint64		unset_flag_bits = 0;
 	int			refcount_change = 0;
 
 	buf_state = LockBufHdr(buf);
@@ -6261,7 +6261,7 @@ static void
 AbortBufferIO(Buffer buffer)
 {
 	BufferDesc *buf_hdr = GetBufferDescriptor(buffer - 1);
-	uint32		buf_state;
+	uint64		buf_state;
 
 	buf_state = LockBufHdr(buf_hdr);
 	Assert(buf_state & (BM_IO_IN_PROGRESS | BM_TAG_VALID));
@@ -6355,10 +6355,10 @@ rlocator_comparator(const void *p1, const void *p2)
 /*
  * Lock buffer header - set BM_LOCKED in buffer state.
  */
-uint32
+uint64
 LockBufHdr(BufferDesc *desc)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	Assert(!BufferIsLocal(BufferDescriptorGetBuffer(desc)));
 
@@ -6369,7 +6369,7 @@ LockBufHdr(BufferDesc *desc)
 		 * the spin-delay infrastructure. The work necessary for that shows up
 		 * in profiles and is rarely necessary.
 		 */
-		old_buf_state = pg_atomic_fetch_or_u32(&desc->state, BM_LOCKED);
+		old_buf_state = pg_atomic_fetch_or_u64(&desc->state, BM_LOCKED);
 		if (likely(!(old_buf_state & BM_LOCKED)))
 			break;				/* got lock */
 
@@ -6382,7 +6382,7 @@ LockBufHdr(BufferDesc *desc)
 			while (old_buf_state & BM_LOCKED)
 			{
 				perform_spin_delay(&delayStatus);
-				old_buf_state = pg_atomic_read_u32(&desc->state);
+				old_buf_state = pg_atomic_read_u64(&desc->state);
 			}
 			finish_spin_delay(&delayStatus);
 		}
@@ -6403,20 +6403,20 @@ LockBufHdr(BufferDesc *desc)
  * Obviously the buffer could be locked by the time the value is returned, so
  * this is primarily useful in CAS style loops.
  */
-pg_noinline uint32
+pg_noinline uint64
 WaitBufHdrUnlocked(BufferDesc *buf)
 {
 	SpinDelayStatus delayStatus;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	init_local_spin_delay(&delayStatus);
 
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
 	while (buf_state & BM_LOCKED)
 	{
 		perform_spin_delay(&delayStatus);
-		buf_state = pg_atomic_read_u32(&buf->state);
+		buf_state = pg_atomic_read_u64(&buf->state);
 	}
 
 	finish_spin_delay(&delayStatus);
@@ -6704,12 +6704,12 @@ ResOwnerPrintBufferPin(Datum res)
 static bool
 EvictUnpinnedBufferInternal(BufferDesc *desc, bool *buffer_flushed)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result;
 
 	*buffer_flushed = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -6803,12 +6803,12 @@ EvictAllUnpinnedBuffers(int32 *buffers_evicted, int32 *buffers_flushed,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -6855,7 +6855,7 @@ EvictRelUnpinnedBuffers(Relation rel, int32 *buffers_evicted,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
@@ -6897,12 +6897,12 @@ static bool
 MarkDirtyUnpinnedBufferInternal(Buffer buf, BufferDesc *desc,
 								bool *buffer_already_dirty)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result = false;
 
 	*buffer_already_dirty = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -7000,7 +7000,7 @@ MarkDirtyRelUnpinnedBuffers(Relation rel,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
@@ -7054,12 +7054,12 @@ MarkDirtyAllUnpinnedBuffers(int32 *buffers_dirtied,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -7110,7 +7110,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		BufferDesc *buf_hdr = is_temp ?
 			GetLocalBufferDescriptor(-buffer - 1)
 			: GetBufferDescriptor(buffer - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * Check that all the buffers are actually ones that could conceivably
@@ -7128,7 +7128,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		}
 
 		if (is_temp)
-			buf_state = pg_atomic_read_u32(&buf_hdr->state);
+			buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		else
 			buf_state = LockBufHdr(buf_hdr);
 
@@ -7166,7 +7166,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		if (is_temp)
 		{
 			buf_state += BUF_REFCOUNT_ONE;
-			pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 		}
 		else
 			UnlockBufHdrExt(buf_hdr, buf_state, 0, 0, 1);
@@ -7352,13 +7352,13 @@ buffer_readv_complete_one(PgAioTargetData *td, uint8 buf_off, Buffer buffer,
 		: GetBufferDescriptor(buffer - 1);
 	BufferTag	tag = buf_hdr->tag;
 	char	   *bufdata = BufferGetBlock(buffer);
-	uint32		set_flag_bits;
+	uint64		set_flag_bits;
 	int			piv_flags;
 
 	/* check that the buffer is in the expected state for a read */
 #ifdef USE_ASSERT_CHECKING
 	{
-		uint32		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 		Assert(buf_state & BM_TAG_VALID);
 		Assert(!(buf_state & BM_VALID));
diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 9a93fb335fc..b7687836188 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -86,7 +86,7 @@ typedef struct BufferAccessStrategyData
 
 /* Prototypes for internal functions */
 static BufferDesc *GetBufferFromRing(BufferAccessStrategy strategy,
-									 uint32 *buf_state);
+									 uint64 *buf_state);
 static void AddBufferToRing(BufferAccessStrategy strategy,
 							BufferDesc *buf);
 
@@ -171,7 +171,7 @@ ClockSweepTick(void)
  *	before returning.
  */
 BufferDesc *
-StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_ring)
+StrategyGetBuffer(BufferAccessStrategy strategy, uint64 *buf_state, bool *from_ring)
 {
 	BufferDesc *buf;
 	int			bgwprocno;
@@ -230,8 +230,8 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 	trycounter = NBuffers;
 	for (;;)
 	{
-		uint32		old_buf_state;
-		uint32		local_buf_state;
+		uint64		old_buf_state;
+		uint64		local_buf_state;
 
 		buf = GetBufferDescriptor(ClockSweepTick());
 
@@ -239,7 +239,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 		 * Check whether the buffer can be used and pin it if so. Do this
 		 * using a CAS loop, to avoid having to lock the buffer header.
 		 */
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			local_buf_state = old_buf_state;
@@ -277,7 +277,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 			{
 				local_buf_state -= BUF_USAGECOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					trycounter = NBuffers;
@@ -289,7 +289,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 				/* pin the buffer if the CAS succeeds */
 				local_buf_state += BUF_REFCOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					/* Found a usable buffer */
@@ -655,12 +655,12 @@ FreeAccessStrategy(BufferAccessStrategy strategy)
  * returning.
  */
 static BufferDesc *
-GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
+GetBufferFromRing(BufferAccessStrategy strategy, uint64 *buf_state)
 {
 	BufferDesc *buf;
 	Buffer		bufnum;
-	uint32		old_buf_state;
-	uint32		local_buf_state;	/* to avoid repeated (de-)referencing */
+	uint64		old_buf_state;
+	uint64		local_buf_state;	/* to avoid repeated (de-)referencing */
 
 
 	/* Advance to next ring slot */
@@ -682,7 +682,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 	 * Check whether the buffer can be used and pin it if so. Do this using a
 	 * CAS loop, to avoid having to lock the buffer header.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 	for (;;)
 	{
 		local_buf_state = old_buf_state;
@@ -710,7 +710,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 		/* pin the buffer if the CAS succeeds */
 		local_buf_state += BUF_REFCOUNT_ONE;
 
-		if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 										   local_buf_state))
 		{
 			*buf_state = local_buf_state;
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index f6e2b1aa288..04a540379a2 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -148,7 +148,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	}
 	else
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		victim_buffer = GetLocalVictimBuffer();
 		bufid = -victim_buffer - 1;
@@ -165,10 +165,10 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		 */
 		bufHdr->tag = newTag;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		buf_state &= ~(BUF_FLAG_MASK | BUF_USAGECOUNT_MASK);
 		buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 		*foundPtr = false;
 	}
@@ -245,12 +245,12 @@ GetLocalVictimBuffer(void)
 
 		if (LocalRefCount[victim_bufid] == 0)
 		{
-			uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 			if (BUF_STATE_GET_USAGECOUNT(buf_state) > 0)
 			{
 				buf_state -= BUF_USAGECOUNT_ONE;
-				pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+				pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 				trycounter = NLocBuffer;
 			}
 			else if (BUF_STATE_GET_REFCOUNT(buf_state) > 0)
@@ -286,13 +286,13 @@ GetLocalVictimBuffer(void)
 	 * this buffer is not referenced but it might still be dirty. if that's
 	 * the case, write it out before reusing it!
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY)
 		FlushLocalBuffer(bufHdr, NULL);
 
 	/*
 	 * Remove the victim buffer from the hashtable and mark as invalid.
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID)
 	{
 		InvalidateLocalBuffer(bufHdr, false);
 
@@ -417,7 +417,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 		if (found)
 		{
 			BufferDesc *existing_hdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			UnpinLocalBuffer(BufferDescriptorGetBuffer(victim_buf_hdr));
 
@@ -428,18 +428,18 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 			/*
 			 * Clear the BM_VALID bit, do StartLocalBufferIO() and proceed.
 			 */
-			buf_state = pg_atomic_read_u32(&existing_hdr->state);
+			buf_state = pg_atomic_read_u64(&existing_hdr->state);
 			Assert(buf_state & BM_TAG_VALID);
 			Assert(!(buf_state & BM_DIRTY));
 			buf_state &= ~BM_VALID;
-			pg_atomic_unlocked_write_u32(&existing_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&existing_hdr->state, buf_state);
 
 			/* no need to loop for local buffers */
 			StartLocalBufferIO(existing_hdr, true, false);
 		}
 		else
 		{
-			uint32		buf_state = pg_atomic_read_u32(&victim_buf_hdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&victim_buf_hdr->state);
 
 			Assert(!(buf_state & (BM_VALID | BM_TAG_VALID | BM_DIRTY | BM_JUST_DIRTIED)));
 
@@ -447,7 +447,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 
 			buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
 
-			pg_atomic_unlocked_write_u32(&victim_buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&victim_buf_hdr->state, buf_state);
 
 			hresult->id = victim_buf_id;
 
@@ -467,13 +467,13 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 	{
 		Buffer		buf = buffers[i];
 		BufferDesc *buf_hdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		buf_state |= BM_VALID;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 
 	*extended_by = extend_by;
@@ -492,7 +492,7 @@ MarkLocalBufferDirty(Buffer buffer)
 {
 	int			bufid;
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsLocal(buffer));
 
@@ -506,14 +506,14 @@ MarkLocalBufferDirty(Buffer buffer)
 
 	bufHdr = GetLocalBufferDescriptor(bufid);
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	if (!(buf_state & BM_DIRTY))
 		pgBufferUsage.local_blks_dirtied++;
 
 	buf_state |= BM_DIRTY;
 
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -522,7 +522,7 @@ MarkLocalBufferDirty(Buffer buffer)
 bool
 StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * With AIO the buffer could have IO in progress, e.g. when there are two
@@ -542,7 +542,7 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 	/* Once we get here, there is definitely no I/O active on this buffer */
 
 	/* Check if someone else already did the I/O */
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 	if (forInput ? (buf_state & BM_VALID) : !(buf_state & BM_DIRTY))
 	{
 		return false;
@@ -559,11 +559,11 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
  * Like TerminateBufferIO, but for local buffers
  */
 void
-TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bits,
+TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint64 set_flag_bits,
 					   bool release_aio)
 {
 	/* Only need to adjust flags */
-	uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+	uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/* BM_IO_IN_PROGRESS isn't currently used for local buffers */
 
@@ -582,7 +582,7 @@ TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bit
 	}
 
 	buf_state |= set_flag_bits;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 	/* local buffers don't track IO using resowners */
 
@@ -606,7 +606,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 {
 	Buffer		buffer = BufferDescriptorGetBuffer(bufHdr);
 	int			bufid = -buffer - 1;
-	uint32		buf_state;
+	uint64		buf_state;
 	LocalBufferLookupEnt *hresult;
 
 	/*
@@ -622,7 +622,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 		Assert(!pgaio_wref_valid(&bufHdr->io_wref));
 	}
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/*
 	 * We need to test not just LocalRefCount[bufid] but also the BufferDesc
@@ -647,7 +647,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 	ClearBufferTag(&bufHdr->tag);
 	buf_state &= ~BUF_FLAG_MASK;
 	buf_state &= ~BUF_USAGECOUNT_MASK;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -671,9 +671,9 @@ DropRelationLocalBuffers(RelFileLocator rlocator, ForkNumber *forkNum,
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (!(buf_state & BM_TAG_VALID) ||
 			!BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -706,9 +706,9 @@ DropRelationAllLocalBuffers(RelFileLocator rlocator)
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if ((buf_state & BM_TAG_VALID) &&
 			BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -804,11 +804,11 @@ InitLocalBuffers(void)
 bool
 PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	Buffer		buffer = BufferDescriptorGetBuffer(buf_hdr);
 	int			bufid = -buffer - 1;
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	if (LocalRefCount[bufid] == 0)
 	{
@@ -819,7 +819,7 @@ PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 		{
 			buf_state += BUF_USAGECOUNT_ONE;
 		}
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/*
 		 * See comment in PinBuffer().
@@ -856,14 +856,14 @@ UnpinLocalBufferNoOwner(Buffer buffer)
 	if (--LocalRefCount[buffid] == 0)
 	{
 		BufferDesc *buf_hdr = GetLocalBufferDescriptor(buffid);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		NLocalPinnedBuffers--;
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state -= BUF_REFCOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/* see comment in UnpinBufferNoOwner */
 		VALGRIND_MAKE_MEM_NOACCESS(LocalBufHdrGetBlock(buf_hdr), BLCKSZ);
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index 0c58e4b265c..529803346ce 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -199,7 +199,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 		for (i = 0; i < NBuffers; i++)
 		{
 			BufferDesc *bufHdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			CHECK_FOR_INTERRUPTS();
 
@@ -615,7 +615,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		CHECK_FOR_INTERRUPTS();
 
@@ -626,7 +626,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 		 * noticeably increase the cost of the function.
 		 */
 		bufHdr = GetBufferDescriptor(i);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (buf_state & BM_VALID)
 		{
@@ -676,7 +676,7 @@ pg_buffercache_usage_counts(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		int			usage_count;
 
 		CHECK_FOR_INTERRUPTS();
diff --git a/src/test/modules/test_aio/test_aio.c b/src/test/modules/test_aio/test_aio.c
index e046b08f3d5..b1aa8af9ec0 100644
--- a/src/test/modules/test_aio/test_aio.c
+++ b/src/test/modules/test_aio/test_aio.c
@@ -308,9 +308,9 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 {
 	Buffer		buf;
 	BufferDesc *buf_hdr;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		was_pinned = false;
-	uint32		unset_bits = 0;
+	uint64		unset_bits = 0;
 
 	/* place buffer in shared buffers without erroring out */
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_ZERO_AND_LOCK, NULL);
@@ -319,7 +319,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	}
 	else
 	{
@@ -340,7 +340,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_state &= ~unset_bits;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 	else
 	{
@@ -489,7 +489,7 @@ invalidate_rel_block(PG_FUNCTION_ARGS)
 
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-			if (pg_atomic_read_u32(&buf_hdr->state) & BM_DIRTY)
+			if (pg_atomic_read_u64(&buf_hdr->state) & BM_DIRTY)
 			{
 				if (BufferIsLocal(buf))
 					FlushLocalBuffer(buf_hdr, NULL);
@@ -572,7 +572,7 @@ buffer_call_terminate_io(PG_FUNCTION_ARGS)
 	bool		io_error = PG_GETARG_BOOL(3);
 	bool		release_aio = PG_GETARG_BOOL(4);
 	bool		clear_dirty = false;
-	uint32		set_flag_bits = 0;
+	uint64		set_flag_bits = 0;
 
 	if (io_error)
 		set_flag_bits |= BM_IO_ERROR;
-- 
2.48.1.76.g4e746b1a31.dirty


--jmawlk4t5yqwiemy
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v10-0004-bufmgr-Implement-buffer-content-locks-independen.patch"



^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* [PATCH v11 1/7] bufmgr: Change BufferDesc.state to be a 64-bit atomic
@ 2026-01-14 01:10  Andres Freund <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Andres Freund @ 2026-01-14 01:10 UTC (permalink / raw)

This is motivated by wanting to merge buffer content locks into
BufferDesc.state in a future commit, rather than having a separate lwlock (see
commit c75ebc657ff for more details). As this change is rather mechanical, it
seems to make sense to split it out into a separate commit, for easier review.

Reviewed-by: Melanie Plageman <[email protected]>
Discussion: https://postgr.es/m/fvfmkr5kk4nyex56ejgxj3uzi63isfxovp2biecb4bspbjrze7@az2pljabhnff
---
 src/include/storage/buf_internals.h           |  51 +++---
 src/include/storage/procnumber.h              |  14 +-
 src/backend/storage/buffer/buf_init.c         |   2 +-
 src/backend/storage/buffer/bufmgr.c           | 170 +++++++++---------
 src/backend/storage/buffer/freelist.c         |  24 +--
 src/backend/storage/buffer/localbuf.c         |  72 ++++----
 contrib/pg_buffercache/pg_buffercache_pages.c |   8 +-
 contrib/pg_prewarm/autoprewarm.c              |   2 +-
 src/test/modules/test_aio/test_aio.c          |  12 +-
 9 files changed, 179 insertions(+), 176 deletions(-)

diff --git a/src/include/storage/buf_internals.h b/src/include/storage/buf_internals.h
index 2f607ea2ac5..e6e788224f5 100644
--- a/src/include/storage/buf_internals.h
+++ b/src/include/storage/buf_internals.h
@@ -30,7 +30,7 @@
 #include "utils/resowner.h"
 
 /*
- * Buffer state is a single 32-bit variable where following data is combined.
+ * Buffer state is a single 64-bit variable where following data is combined.
  *
  * State of the buffer itself (in order):
  * - 18 bits refcount
@@ -40,6 +40,9 @@
  * Combining these values allows to perform some operations without locking
  * the buffer header, by modifying them together with a CAS loop.
  *
+ * NB: A future commit will use a significant portion of the remaining bits to
+ * implement buffer locking as part of the state variable.
+ *
  * The definition of buffer state components is below.
  */
 #define BUF_REFCOUNT_BITS 18
@@ -52,27 +55,27 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
 /* refcount related definitions */
 #define BUF_REFCOUNT_ONE 1
 #define BUF_REFCOUNT_MASK \
-	((1U << BUF_REFCOUNT_BITS) - 1)
+	((UINT64CONST(1) << BUF_REFCOUNT_BITS) - 1)
 
 /* usage count related definitions */
 #define BUF_USAGECOUNT_SHIFT \
 	BUF_REFCOUNT_BITS
 #define BUF_USAGECOUNT_MASK \
-	(((1U << BUF_USAGECOUNT_BITS) - 1) << (BUF_USAGECOUNT_SHIFT))
+	(((UINT64CONST(1) << BUF_USAGECOUNT_BITS) - 1) << (BUF_USAGECOUNT_SHIFT))
 #define BUF_USAGECOUNT_ONE \
-	(1U << BUF_REFCOUNT_BITS)
+	(UINT64CONST(1) << BUF_REFCOUNT_BITS)
 
 /* flags related definitions */
 #define BUF_FLAG_SHIFT \
 	(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS)
 #define BUF_FLAG_MASK \
-	(((1U << BUF_FLAG_BITS) - 1) << BUF_FLAG_SHIFT)
+	(((UINT64CONST(1) << BUF_FLAG_BITS) - 1) << BUF_FLAG_SHIFT)
 
 /* Get refcount and usagecount from buffer state */
 #define BUF_STATE_GET_REFCOUNT(state) \
-	((state) & BUF_REFCOUNT_MASK)
+	((uint32)((state) & BUF_REFCOUNT_MASK))
 #define BUF_STATE_GET_USAGECOUNT(state) \
-	(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT)
+	((uint32)(((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT))
 
 /*
  * Flags for buffer descriptors
@@ -82,7 +85,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 
 #define BUF_DEFINE_FLAG(flagno)	\
-	(1U << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + (flagno)))
+	(UINT64CONST(1) << (BUF_FLAG_SHIFT + (flagno)))
 
 /* buffer header is locked */
 #define BM_LOCKED					BUF_DEFINE_FLAG( 0)
@@ -115,7 +118,7 @@ StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
  */
 #define BM_MAX_USAGE_COUNT	5
 
-StaticAssertDecl(BM_MAX_USAGE_COUNT < (1 << BUF_USAGECOUNT_BITS),
+StaticAssertDecl(BM_MAX_USAGE_COUNT < (UINT64CONST(1) << BUF_USAGECOUNT_BITS),
 				 "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
 StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
 				 "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
@@ -280,8 +283,8 @@ BufMappingPartitionLockByIndex(uint32 index)
  * We use this same struct for local buffer headers, but the locks are not
  * used and not all of the flag bits are useful either. To avoid unnecessary
  * overhead, manipulations of the state field should be done without actual
- * atomic operations (i.e. only pg_atomic_read_u32() and
- * pg_atomic_unlocked_write_u32()).
+ * atomic operations (i.e. only pg_atomic_read_u64() and
+ * pg_atomic_unlocked_write_u64()).
  *
  * Be careful to avoid increasing the size of the struct when adding or
  * reordering members.  Keeping it below 64 bytes (the most common CPU
@@ -309,7 +312,7 @@ typedef struct BufferDesc
 	 * State of the buffer, containing flags, refcount and usagecount. See
 	 * BUF_* and BM_* defines at the top of this file.
 	 */
-	pg_atomic_uint32 state;
+	pg_atomic_uint64 state;
 
 	/*
 	 * Backend of pin-count waiter. The buffer header spinlock needs to be
@@ -415,7 +418,7 @@ BufferDescriptorGetContentLock(const BufferDesc *bdesc)
  * Functions for acquiring/releasing a shared buffer header's spinlock.  Do
  * not apply these to local buffers!
  */
-extern uint32 LockBufHdr(BufferDesc *desc);
+extern uint64 LockBufHdr(BufferDesc *desc);
 
 /*
  * Unlock the buffer header.
@@ -426,9 +429,9 @@ extern uint32 LockBufHdr(BufferDesc *desc);
 static inline void
 UnlockBufHdr(BufferDesc *desc)
 {
-	Assert(pg_atomic_read_u32(&desc->state) & BM_LOCKED);
+	Assert(pg_atomic_read_u64(&desc->state) & BM_LOCKED);
 
-	pg_atomic_fetch_sub_u32(&desc->state, BM_LOCKED);
+	pg_atomic_fetch_sub_u64(&desc->state, BM_LOCKED);
 }
 
 /*
@@ -439,14 +442,14 @@ UnlockBufHdr(BufferDesc *desc)
  * Note that this approach would not work for usagecount, since we need to cap
  * the usagecount at BM_MAX_USAGE_COUNT.
  */
-static inline uint32
-UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
-				uint32 set_bits, uint32 unset_bits,
+static inline uint64
+UnlockBufHdrExt(BufferDesc *desc, uint64 old_buf_state,
+				uint64 set_bits, uint64 unset_bits,
 				int refcount_change)
 {
 	for (;;)
 	{
-		uint32		buf_state = old_buf_state;
+		uint64		buf_state = old_buf_state;
 
 		Assert(buf_state & BM_LOCKED);
 
@@ -457,7 +460,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 		if (refcount_change != 0)
 			buf_state += BUF_REFCOUNT_ONE * refcount_change;
 
-		if (pg_atomic_compare_exchange_u32(&desc->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&desc->state, &old_buf_state,
 										   buf_state))
 		{
 			return old_buf_state;
@@ -465,7 +468,7 @@ UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
 	}
 }
 
-extern uint32 WaitBufHdrUnlocked(BufferDesc *buf);
+extern uint64 WaitBufHdrUnlocked(BufferDesc *buf);
 
 /* in bufmgr.c */
 
@@ -525,14 +528,14 @@ extern void TrackNewBufferPin(Buffer buf);
 
 /* solely to make it easier to write tests */
 extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
-extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 							  bool forget_owner, bool release_aio);
 
 
 /* freelist.c */
 extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
 extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
-									 uint32 *buf_state, bool *from_ring);
+									 uint64 *buf_state, bool *from_ring);
 extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
 								 BufferDesc *buf, bool from_ring);
 
@@ -568,7 +571,7 @@ extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
 										  uint32 *extended_by);
 extern void MarkLocalBufferDirty(Buffer buffer);
 extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
-								   uint32 set_flag_bits, bool release_aio);
+								   uint64 set_flag_bits, bool release_aio);
 extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
 extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
 extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
diff --git a/src/include/storage/procnumber.h b/src/include/storage/procnumber.h
index 30c360ad350..bd9cb3891cc 100644
--- a/src/include/storage/procnumber.h
+++ b/src/include/storage/procnumber.h
@@ -27,13 +27,13 @@ typedef int ProcNumber;
 
 /*
  * Note: MAX_BACKENDS_BITS is 18 as that is the space available for buffer
- * refcounts in buf_internals.h.  This limitation could be lifted by using a
- * 64bit state; but it's unlikely to be worthwhile as 2^18-1 backends exceed
- * currently realistic configurations. Even if that limitation were removed,
- * we still could not a) exceed 2^23-1 because inval.c stores the ProcNumber
- * as a 3-byte signed integer, b) INT_MAX/4 because some places compute
- * 4*MaxBackends without any overflow check.  We check that the configured
- * number of backends does not exceed MAX_BACKENDS in InitializeMaxBackends().
+ * refcounts in buf_internals.h.  This limitation could be lifted, but it's
+ * unlikely to be worthwhile as 2^18-1 backends exceed currently realistic
+ * configurations. Even if that limitation were removed, we still could not a)
+ * exceed 2^23-1 because inval.c stores the ProcNumber as a 3-byte signed
+ * integer, b) INT_MAX/4 because some places compute 4*MaxBackends without any
+ * overflow check.  We check that the configured number of backends does not
+ * exceed MAX_BACKENDS in InitializeMaxBackends().
  */
 #define MAX_BACKENDS_BITS		18
 #define MAX_BACKENDS			((1U << MAX_BACKENDS_BITS)-1)
diff --git a/src/backend/storage/buffer/buf_init.c b/src/backend/storage/buffer/buf_init.c
index 9a312bcc7b3..7d894522526 100644
--- a/src/backend/storage/buffer/buf_init.c
+++ b/src/backend/storage/buffer/buf_init.c
@@ -121,7 +121,7 @@ BufferManagerShmemInit(void)
 
 			ClearBufferTag(&buf->tag);
 
-			pg_atomic_init_u32(&buf->state, 0);
+			pg_atomic_init_u64(&buf->state, 0);
 			buf->wait_backend_pgprocno = INVALID_PROC_NUMBER;
 
 			buf->buf_id = i;
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index a036c2aa275..b0de8e45d4d 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -780,7 +780,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 {
 	BufferDesc *bufHdr;
 	BufferTag	tag;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(recent_buffer));
 
@@ -793,7 +793,7 @@ ReadRecentBuffer(RelFileLocator rlocator, ForkNumber forkNum, BlockNumber blockN
 		int			b = -recent_buffer - 1;
 
 		bufHdr = GetLocalBufferDescriptor(b);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		/* Is it still valid and holding the right tag? */
 		if ((buf_state & BM_VALID) && BufferTagsEqual(&tag, &bufHdr->tag))
@@ -1386,8 +1386,8 @@ StartReadBuffersImpl(ReadBuffersOperation *operation,
 				bufHdr = GetLocalBufferDescriptor(-buffers[i] - 1);
 			else
 				bufHdr = GetBufferDescriptor(buffers[i] - 1);
-			Assert(pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID);
-			found = pg_atomic_read_u32(&bufHdr->state) & BM_VALID;
+			Assert(pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID);
+			found = pg_atomic_read_u64(&bufHdr->state) & BM_VALID;
 		}
 		else
 		{
@@ -1613,10 +1613,10 @@ CheckReadBuffersOperation(ReadBuffersOperation *operation, bool is_complete)
 			GetBufferDescriptor(buffer - 1);
 
 		Assert(BufferGetBlockNumber(buffer) == operation->blocknum + i);
-		Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_TAG_VALID);
+		Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_TAG_VALID);
 
 		if (i < operation->nblocks_done)
-			Assert(pg_atomic_read_u32(&buf_hdr->state) & BM_VALID);
+			Assert(pg_atomic_read_u64(&buf_hdr->state) & BM_VALID);
 	}
 #endif
 }
@@ -2083,8 +2083,8 @@ BufferAlloc(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 	int			existing_buf_id;
 	Buffer		victim_buffer;
 	BufferDesc *victim_buf_hdr;
-	uint32		victim_buf_state;
-	uint32		set_bits = 0;
+	uint64		victim_buf_state;
+	uint64		set_bits = 0;
 
 	/* Make sure we will have room to remember the buffer pin */
 	ResourceOwnerEnlarge(CurrentResourceOwner);
@@ -2251,7 +2251,7 @@ InvalidateBuffer(BufferDesc *buf)
 	uint32		oldHash;		/* hash value for oldTag */
 	LWLock	   *oldPartitionLock;	/* buffer partition lock for it */
 	uint32		oldFlags;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/* Save the original buffer tag before dropping the spinlock */
 	oldTag = buf->tag;
@@ -2342,7 +2342,7 @@ retry:
 static bool
 InvalidateVictimBuffer(BufferDesc *buf_hdr)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	uint32		hash;
 	LWLock	   *partition_lock;
 	BufferTag	tag;
@@ -2402,10 +2402,10 @@ InvalidateVictimBuffer(BufferDesc *buf_hdr)
 
 	LWLockRelease(partition_lock);
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	Assert(!(buf_state & (BM_DIRTY | BM_VALID | BM_TAG_VALID)));
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
-	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u32(&buf_hdr->state)) > 0);
+	Assert(BUF_STATE_GET_REFCOUNT(pg_atomic_read_u64(&buf_hdr->state)) > 0);
 
 	return true;
 }
@@ -2415,7 +2415,7 @@ GetVictimBuffer(BufferAccessStrategy strategy, IOContext io_context)
 {
 	BufferDesc *buf_hdr;
 	Buffer		buf;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		from_ring;
 
 	/*
@@ -2548,7 +2548,7 @@ again:
 
 	/* a final set of sanity checks */
 #ifdef USE_ASSERT_CHECKING
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	Assert(BUF_STATE_GET_REFCOUNT(buf_state) == 1);
 	Assert(!(buf_state & (BM_TAG_VALID | BM_VALID | BM_DIRTY)));
@@ -2839,13 +2839,13 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
 			 */
 			do
 			{
-				pg_atomic_fetch_and_u32(&existing_hdr->state, ~BM_VALID);
+				pg_atomic_fetch_and_u64(&existing_hdr->state, ~BM_VALID);
 			} while (!StartBufferIO(existing_hdr, true, false));
 		}
 		else
 		{
-			uint32		buf_state;
-			uint32		set_bits = 0;
+			uint64		buf_state;
+			uint64		set_bits = 0;
 
 			buf_state = LockBufHdr(victim_buf_hdr);
 
@@ -3021,7 +3021,7 @@ BufferIsDirty(Buffer buffer)
 		Assert(BufferIsLockedByMeInMode(buffer, BUFFER_LOCK_EXCLUSIVE));
 	}
 
-	return pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY;
+	return pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY;
 }
 
 /*
@@ -3037,8 +3037,8 @@ void
 MarkBufferDirty(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
-	uint32		old_buf_state;
+	uint64		buf_state;
+	uint64		old_buf_state;
 
 	if (!BufferIsValid(buffer))
 		elog(ERROR, "bad buffer ID: %d", buffer);
@@ -3058,7 +3058,7 @@ MarkBufferDirty(Buffer buffer)
 	 * NB: We have to wait for the buffer header spinlock to be not held, as
 	 * TerminateBufferIO() relies on the spinlock.
 	 */
-	old_buf_state = pg_atomic_read_u32(&bufHdr->state);
+	old_buf_state = pg_atomic_read_u64(&bufHdr->state);
 	for (;;)
 	{
 		if (old_buf_state & BM_LOCKED)
@@ -3069,7 +3069,7 @@ MarkBufferDirty(Buffer buffer)
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state |= BM_DIRTY | BM_JUST_DIRTIED;
 
-		if (pg_atomic_compare_exchange_u32(&bufHdr->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&bufHdr->state, &old_buf_state,
 										   buf_state))
 			break;
 	}
@@ -3173,10 +3173,10 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 
 	if (ref == NULL)
 	{
-		uint32		buf_state;
-		uint32		old_buf_state;
+		uint64		buf_state;
+		uint64		old_buf_state;
 
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			if (unlikely(skip_if_not_valid && !(old_buf_state & BM_VALID)))
@@ -3210,7 +3210,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 					buf_state += BUF_USAGECOUNT_ONE;
 			}
 
-			if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+			if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 											   buf_state))
 			{
 				result = (buf_state & BM_VALID) != 0;
@@ -3237,7 +3237,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 		 * that the buffer page is legitimately non-accessible here.  We
 		 * cannot meddle with that.
 		 */
-		result = (pg_atomic_read_u32(&buf->state) & BM_VALID) != 0;
+		result = (pg_atomic_read_u64(&buf->state) & BM_VALID) != 0;
 
 		Assert(ref->data.refcount > 0);
 		ref->data.refcount++;
@@ -3272,7 +3272,7 @@ PinBuffer(BufferDesc *buf, BufferAccessStrategy strategy,
 static void
 PinBuffer_Locked(BufferDesc *buf)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	/*
 	 * As explained, We don't expect any preexisting pins. That allows us to
@@ -3284,7 +3284,7 @@ PinBuffer_Locked(BufferDesc *buf)
 	 * Since we hold the buffer spinlock, we can update the buffer state and
 	 * release the lock in one operation.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 
 	UnlockBufHdrExt(buf, old_buf_state,
 					0, 0, 1);
@@ -3314,7 +3314,7 @@ WakePinCountWaiter(BufferDesc *buf)
 	 * BM_PIN_COUNT_WAITER if it stops waiting for a reason other than this
 	 * backend waking it up.
 	 */
-	uint32		buf_state = LockBufHdr(buf);
+	uint64		buf_state = LockBufHdr(buf);
 
 	if ((buf_state & BM_PIN_COUNT_WAITER) &&
 		BUF_STATE_GET_REFCOUNT(buf_state) == 1)
@@ -3361,7 +3361,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 	ref->data.refcount--;
 	if (ref->data.refcount == 0)
 	{
-		uint32		old_buf_state;
+		uint64		old_buf_state;
 
 		/*
 		 * Mark buffer non-accessible to Valgrind.
@@ -3379,7 +3379,7 @@ UnpinBufferNoOwner(BufferDesc *buf)
 		Assert(!LWLockHeldByMe(BufferDescriptorGetContentLock(buf)));
 
 		/* decrement the shared reference count */
-		old_buf_state = pg_atomic_fetch_sub_u32(&buf->state, BUF_REFCOUNT_ONE);
+		old_buf_state = pg_atomic_fetch_sub_u64(&buf->state, BUF_REFCOUNT_ONE);
 
 		/* Support LockBufferForCleanup() */
 		if (old_buf_state & BM_PIN_COUNT_WAITER)
@@ -3436,7 +3436,7 @@ TrackNewBufferPin(Buffer buf)
 static void
 BufferSync(int flags)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	int			buf_id;
 	int			num_to_scan;
 	int			num_spaces;
@@ -3446,7 +3446,7 @@ BufferSync(int flags)
 	Oid			last_tsid;
 	binaryheap *ts_heap;
 	int			i;
-	uint32		mask = BM_DIRTY;
+	uint64		mask = BM_DIRTY;
 	WritebackContext wb_context;
 
 	/*
@@ -3478,7 +3478,7 @@ BufferSync(int flags)
 	for (buf_id = 0; buf_id < NBuffers; buf_id++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
-		uint32		set_bits = 0;
+		uint64		set_bits = 0;
 
 		/*
 		 * Header spinlock is enough to examine BM_DIRTY, see comment in
@@ -3645,7 +3645,7 @@ BufferSync(int flags)
 		 * write the buffer though we didn't need to.  It doesn't seem worth
 		 * guarding against this, though.
 		 */
-		if (pg_atomic_read_u32(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
+		if (pg_atomic_read_u64(&bufHdr->state) & BM_CHECKPOINT_NEEDED)
 		{
 			if (SyncOneBuffer(buf_id, false, &wb_context) & BUF_WRITTEN)
 			{
@@ -4015,7 +4015,7 @@ SyncOneBuffer(int buf_id, bool skip_recently_used, WritebackContext *wb_context)
 {
 	BufferDesc *bufHdr = GetBufferDescriptor(buf_id);
 	int			result = 0;
-	uint32		buf_state;
+	uint64		buf_state;
 	BufferTag	tag;
 
 	/* Make sure we can handle the pin */
@@ -4264,7 +4264,7 @@ DebugPrintBufferRefcount(Buffer buffer)
 	int32		loccount;
 	char	   *result;
 	ProcNumber	backend;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
@@ -4281,9 +4281,9 @@ DebugPrintBufferRefcount(Buffer buffer)
 	}
 
 	/* theoretically we should lock the bufHdr here */
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
-	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
+	result = psprintf("[%03d] (rel=%s, blockNum=%u, flags=0x%" PRIx64 ", refcount=%u %d)",
 					  buffer,
 					  relpathbackend(BufTagGetRelFileLocator(&buf->tag), backend,
 									 BufTagGetForkNum(&buf->tag)).str,
@@ -4383,7 +4383,7 @@ FlushBuffer(BufferDesc *buf, SMgrRelation reln, IOObject io_object,
 	instr_time	io_start;
 	Block		bufBlock;
 	char	   *bufToWrite;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * Try to start an I/O operation.  If StartBufferIO returns false, then
@@ -4581,7 +4581,7 @@ BufferIsPermanent(Buffer buffer)
 	 * not random garbage.
 	 */
 	bufHdr = GetBufferDescriptor(buffer - 1);
-	return (pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT) != 0;
+	return (pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT) != 0;
 }
 
 /*
@@ -5044,11 +5044,11 @@ FlushRelationBuffers(Relation rel)
 	{
 		for (i = 0; i < NLocBuffer; i++)
 		{
-			uint32		buf_state;
+			uint64		buf_state;
 
 			bufHdr = GetLocalBufferDescriptor(i);
 			if (BufTagMatchesRelFileLocator(&bufHdr->tag, &rel->rd_locator) &&
-				((buf_state = pg_atomic_read_u32(&bufHdr->state)) &
+				((buf_state = pg_atomic_read_u64(&bufHdr->state)) &
 				 (BM_VALID | BM_DIRTY)) == (BM_VALID | BM_DIRTY))
 			{
 				ErrorContextCallback errcallback;
@@ -5084,7 +5084,7 @@ FlushRelationBuffers(Relation rel)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5156,7 +5156,7 @@ FlushRelationsAllBuffers(SMgrRelation *smgrs, int nrels)
 	{
 		SMgrSortArray *srelent = NULL;
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * As in DropRelationBuffers, an unlocked precheck should be safe and
@@ -5405,7 +5405,7 @@ FlushDatabaseBuffers(Oid dbid)
 
 	for (i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		bufHdr = GetBufferDescriptor(i);
 
@@ -5553,13 +5553,13 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 	 * is only intended to be used in cases where failing to write out the
 	 * data would be harmless anyway, it doesn't really matter.
 	 */
-	if ((pg_atomic_read_u32(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
+	if ((pg_atomic_read_u64(&bufHdr->state) & (BM_DIRTY | BM_JUST_DIRTIED)) !=
 		(BM_DIRTY | BM_JUST_DIRTIED))
 	{
 		XLogRecPtr	lsn = InvalidXLogRecPtr;
 		bool		dirtied = false;
 		bool		delayChkptFlags = false;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * If we need to protect hint bit updates from torn writes, WAL-log a
@@ -5571,7 +5571,7 @@ MarkBufferDirtyHint(Buffer buffer, bool buffer_std)
 		 * when we call XLogInsert() since the value changes dynamically.
 		 */
 		if (XLogHintBitIsNeeded() &&
-			(pg_atomic_read_u32(&bufHdr->state) & BM_PERMANENT))
+			(pg_atomic_read_u64(&bufHdr->state) & BM_PERMANENT))
 		{
 			/*
 			 * If we must not write WAL, due to a relfilelocator-specific
@@ -5671,8 +5671,8 @@ UnlockBuffers(void)
 
 	if (buf)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		buf_state = LockBufHdr(buf);
 
@@ -5803,8 +5803,8 @@ LockBufferForCleanup(Buffer buffer)
 
 	for (;;)
 	{
-		uint32		buf_state;
-		uint32		unset_bits = 0;
+		uint64		buf_state;
+		uint64		unset_bits = 0;
 
 		/* Try to acquire lock */
 		LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
@@ -5952,7 +5952,7 @@ bool
 ConditionalLockBufferForCleanup(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state,
+	uint64		buf_state,
 				refcount;
 
 	Assert(BufferIsValid(buffer));
@@ -6010,7 +6010,7 @@ bool
 IsBufferCleanupOK(Buffer buffer)
 {
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsValid(buffer));
 
@@ -6066,7 +6066,7 @@ WaitIO(BufferDesc *buf)
 	ConditionVariablePrepareToSleep(cv);
 	for (;;)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 		PgAioWaitRef iow;
 
 		/*
@@ -6140,7 +6140,7 @@ WaitIO(BufferDesc *buf)
 bool
 StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	ResourceOwnerEnlarge(CurrentResourceOwner);
 
@@ -6196,11 +6196,11 @@ StartBufferIO(BufferDesc *buf, bool forInput, bool nowait)
  * is being released)
  */
 void
-TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
+TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint64 set_flag_bits,
 				  bool forget_owner, bool release_aio)
 {
-	uint32		buf_state;
-	uint32		unset_flag_bits = 0;
+	uint64		buf_state;
+	uint64		unset_flag_bits = 0;
 	int			refcount_change = 0;
 
 	buf_state = LockBufHdr(buf);
@@ -6261,7 +6261,7 @@ static void
 AbortBufferIO(Buffer buffer)
 {
 	BufferDesc *buf_hdr = GetBufferDescriptor(buffer - 1);
-	uint32		buf_state;
+	uint64		buf_state;
 
 	buf_state = LockBufHdr(buf_hdr);
 	Assert(buf_state & (BM_IO_IN_PROGRESS | BM_TAG_VALID));
@@ -6355,10 +6355,10 @@ rlocator_comparator(const void *p1, const void *p2)
 /*
  * Lock buffer header - set BM_LOCKED in buffer state.
  */
-uint32
+uint64
 LockBufHdr(BufferDesc *desc)
 {
-	uint32		old_buf_state;
+	uint64		old_buf_state;
 
 	Assert(!BufferIsLocal(BufferDescriptorGetBuffer(desc)));
 
@@ -6369,7 +6369,7 @@ LockBufHdr(BufferDesc *desc)
 		 * the spin-delay infrastructure. The work necessary for that shows up
 		 * in profiles and is rarely necessary.
 		 */
-		old_buf_state = pg_atomic_fetch_or_u32(&desc->state, BM_LOCKED);
+		old_buf_state = pg_atomic_fetch_or_u64(&desc->state, BM_LOCKED);
 		if (likely(!(old_buf_state & BM_LOCKED)))
 			break;				/* got lock */
 
@@ -6382,7 +6382,7 @@ LockBufHdr(BufferDesc *desc)
 			while (old_buf_state & BM_LOCKED)
 			{
 				perform_spin_delay(&delayStatus);
-				old_buf_state = pg_atomic_read_u32(&desc->state);
+				old_buf_state = pg_atomic_read_u64(&desc->state);
 			}
 			finish_spin_delay(&delayStatus);
 		}
@@ -6403,20 +6403,20 @@ LockBufHdr(BufferDesc *desc)
  * Obviously the buffer could be locked by the time the value is returned, so
  * this is primarily useful in CAS style loops.
  */
-pg_noinline uint32
+pg_noinline uint64
 WaitBufHdrUnlocked(BufferDesc *buf)
 {
 	SpinDelayStatus delayStatus;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	init_local_spin_delay(&delayStatus);
 
-	buf_state = pg_atomic_read_u32(&buf->state);
+	buf_state = pg_atomic_read_u64(&buf->state);
 
 	while (buf_state & BM_LOCKED)
 	{
 		perform_spin_delay(&delayStatus);
-		buf_state = pg_atomic_read_u32(&buf->state);
+		buf_state = pg_atomic_read_u64(&buf->state);
 	}
 
 	finish_spin_delay(&delayStatus);
@@ -6704,12 +6704,12 @@ ResOwnerPrintBufferPin(Datum res)
 static bool
 EvictUnpinnedBufferInternal(BufferDesc *desc, bool *buffer_flushed)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result;
 
 	*buffer_flushed = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -6803,12 +6803,12 @@ EvictAllUnpinnedBuffers(int32 *buffers_evicted, int32 *buffers_flushed,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -6855,7 +6855,7 @@ EvictRelUnpinnedBuffers(Relation rel, int32 *buffers_evicted,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_flushed;
 
 		CHECK_FOR_INTERRUPTS();
@@ -6897,12 +6897,12 @@ static bool
 MarkDirtyUnpinnedBufferInternal(Buffer buf, BufferDesc *desc,
 								bool *buffer_already_dirty)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		result = false;
 
 	*buffer_already_dirty = false;
 
-	buf_state = pg_atomic_read_u32(&(desc->state));
+	buf_state = pg_atomic_read_u64(&(desc->state));
 	Assert(buf_state & BM_LOCKED);
 
 	if ((buf_state & BM_VALID) == 0)
@@ -7000,7 +7000,7 @@ MarkDirtyRelUnpinnedBuffers(Relation rel,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state = pg_atomic_read_u32(&(desc->state));
+		uint64		buf_state = pg_atomic_read_u64(&(desc->state));
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
@@ -7054,12 +7054,12 @@ MarkDirtyAllUnpinnedBuffers(int32 *buffers_dirtied,
 	for (int buf = 1; buf <= NBuffers; buf++)
 	{
 		BufferDesc *desc = GetBufferDescriptor(buf - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 		bool		buffer_already_dirty;
 
 		CHECK_FOR_INTERRUPTS();
 
-		buf_state = pg_atomic_read_u32(&desc->state);
+		buf_state = pg_atomic_read_u64(&desc->state);
 		if (!(buf_state & BM_VALID))
 			continue;
 
@@ -7110,7 +7110,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		BufferDesc *buf_hdr = is_temp ?
 			GetLocalBufferDescriptor(-buffer - 1)
 			: GetBufferDescriptor(buffer - 1);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		/*
 		 * Check that all the buffers are actually ones that could conceivably
@@ -7128,7 +7128,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		}
 
 		if (is_temp)
-			buf_state = pg_atomic_read_u32(&buf_hdr->state);
+			buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		else
 			buf_state = LockBufHdr(buf_hdr);
 
@@ -7166,7 +7166,7 @@ buffer_stage_common(PgAioHandle *ioh, bool is_write, bool is_temp)
 		if (is_temp)
 		{
 			buf_state += BUF_REFCOUNT_ONE;
-			pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 		}
 		else
 			UnlockBufHdrExt(buf_hdr, buf_state, 0, 0, 1);
@@ -7352,13 +7352,13 @@ buffer_readv_complete_one(PgAioTargetData *td, uint8 buf_off, Buffer buffer,
 		: GetBufferDescriptor(buffer - 1);
 	BufferTag	tag = buf_hdr->tag;
 	char	   *bufdata = BufferGetBlock(buffer);
-	uint32		set_flag_bits;
+	uint64		set_flag_bits;
 	int			piv_flags;
 
 	/* check that the buffer is in the expected state for a read */
 #ifdef USE_ASSERT_CHECKING
 	{
-		uint32		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 		Assert(buf_state & BM_TAG_VALID);
 		Assert(!(buf_state & BM_VALID));
diff --git a/src/backend/storage/buffer/freelist.c b/src/backend/storage/buffer/freelist.c
index 9a93fb335fc..b7687836188 100644
--- a/src/backend/storage/buffer/freelist.c
+++ b/src/backend/storage/buffer/freelist.c
@@ -86,7 +86,7 @@ typedef struct BufferAccessStrategyData
 
 /* Prototypes for internal functions */
 static BufferDesc *GetBufferFromRing(BufferAccessStrategy strategy,
-									 uint32 *buf_state);
+									 uint64 *buf_state);
 static void AddBufferToRing(BufferAccessStrategy strategy,
 							BufferDesc *buf);
 
@@ -171,7 +171,7 @@ ClockSweepTick(void)
  *	before returning.
  */
 BufferDesc *
-StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_ring)
+StrategyGetBuffer(BufferAccessStrategy strategy, uint64 *buf_state, bool *from_ring)
 {
 	BufferDesc *buf;
 	int			bgwprocno;
@@ -230,8 +230,8 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 	trycounter = NBuffers;
 	for (;;)
 	{
-		uint32		old_buf_state;
-		uint32		local_buf_state;
+		uint64		old_buf_state;
+		uint64		local_buf_state;
 
 		buf = GetBufferDescriptor(ClockSweepTick());
 
@@ -239,7 +239,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 		 * Check whether the buffer can be used and pin it if so. Do this
 		 * using a CAS loop, to avoid having to lock the buffer header.
 		 */
-		old_buf_state = pg_atomic_read_u32(&buf->state);
+		old_buf_state = pg_atomic_read_u64(&buf->state);
 		for (;;)
 		{
 			local_buf_state = old_buf_state;
@@ -277,7 +277,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 			{
 				local_buf_state -= BUF_USAGECOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					trycounter = NBuffers;
@@ -289,7 +289,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state, bool *from_r
 				/* pin the buffer if the CAS succeeds */
 				local_buf_state += BUF_REFCOUNT_ONE;
 
-				if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+				if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 												   local_buf_state))
 				{
 					/* Found a usable buffer */
@@ -655,12 +655,12 @@ FreeAccessStrategy(BufferAccessStrategy strategy)
  * returning.
  */
 static BufferDesc *
-GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
+GetBufferFromRing(BufferAccessStrategy strategy, uint64 *buf_state)
 {
 	BufferDesc *buf;
 	Buffer		bufnum;
-	uint32		old_buf_state;
-	uint32		local_buf_state;	/* to avoid repeated (de-)referencing */
+	uint64		old_buf_state;
+	uint64		local_buf_state;	/* to avoid repeated (de-)referencing */
 
 
 	/* Advance to next ring slot */
@@ -682,7 +682,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 	 * Check whether the buffer can be used and pin it if so. Do this using a
 	 * CAS loop, to avoid having to lock the buffer header.
 	 */
-	old_buf_state = pg_atomic_read_u32(&buf->state);
+	old_buf_state = pg_atomic_read_u64(&buf->state);
 	for (;;)
 	{
 		local_buf_state = old_buf_state;
@@ -710,7 +710,7 @@ GetBufferFromRing(BufferAccessStrategy strategy, uint32 *buf_state)
 		/* pin the buffer if the CAS succeeds */
 		local_buf_state += BUF_REFCOUNT_ONE;
 
-		if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state,
+		if (pg_atomic_compare_exchange_u64(&buf->state, &old_buf_state,
 										   local_buf_state))
 		{
 			*buf_state = local_buf_state;
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index f6e2b1aa288..04a540379a2 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -148,7 +148,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	}
 	else
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		victim_buffer = GetLocalVictimBuffer();
 		bufid = -victim_buffer - 1;
@@ -165,10 +165,10 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		 */
 		bufHdr->tag = newTag;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		buf_state &= ~(BUF_FLAG_MASK | BUF_USAGECOUNT_MASK);
 		buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 		*foundPtr = false;
 	}
@@ -245,12 +245,12 @@ GetLocalVictimBuffer(void)
 
 		if (LocalRefCount[victim_bufid] == 0)
 		{
-			uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 			if (BUF_STATE_GET_USAGECOUNT(buf_state) > 0)
 			{
 				buf_state -= BUF_USAGECOUNT_ONE;
-				pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+				pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 				trycounter = NLocBuffer;
 			}
 			else if (BUF_STATE_GET_REFCOUNT(buf_state) > 0)
@@ -286,13 +286,13 @@ GetLocalVictimBuffer(void)
 	 * this buffer is not referenced but it might still be dirty. if that's
 	 * the case, write it out before reusing it!
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_DIRTY)
 		FlushLocalBuffer(bufHdr, NULL);
 
 	/*
 	 * Remove the victim buffer from the hashtable and mark as invalid.
 	 */
-	if (pg_atomic_read_u32(&bufHdr->state) & BM_TAG_VALID)
+	if (pg_atomic_read_u64(&bufHdr->state) & BM_TAG_VALID)
 	{
 		InvalidateLocalBuffer(bufHdr, false);
 
@@ -417,7 +417,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 		if (found)
 		{
 			BufferDesc *existing_hdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			UnpinLocalBuffer(BufferDescriptorGetBuffer(victim_buf_hdr));
 
@@ -428,18 +428,18 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 			/*
 			 * Clear the BM_VALID bit, do StartLocalBufferIO() and proceed.
 			 */
-			buf_state = pg_atomic_read_u32(&existing_hdr->state);
+			buf_state = pg_atomic_read_u64(&existing_hdr->state);
 			Assert(buf_state & BM_TAG_VALID);
 			Assert(!(buf_state & BM_DIRTY));
 			buf_state &= ~BM_VALID;
-			pg_atomic_unlocked_write_u32(&existing_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&existing_hdr->state, buf_state);
 
 			/* no need to loop for local buffers */
 			StartLocalBufferIO(existing_hdr, true, false);
 		}
 		else
 		{
-			uint32		buf_state = pg_atomic_read_u32(&victim_buf_hdr->state);
+			uint64		buf_state = pg_atomic_read_u64(&victim_buf_hdr->state);
 
 			Assert(!(buf_state & (BM_VALID | BM_TAG_VALID | BM_DIRTY | BM_JUST_DIRTIED)));
 
@@ -447,7 +447,7 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 
 			buf_state |= BM_TAG_VALID | BUF_USAGECOUNT_ONE;
 
-			pg_atomic_unlocked_write_u32(&victim_buf_hdr->state, buf_state);
+			pg_atomic_unlocked_write_u64(&victim_buf_hdr->state, buf_state);
 
 			hresult->id = victim_buf_id;
 
@@ -467,13 +467,13 @@ ExtendBufferedRelLocal(BufferManagerRelation bmr,
 	{
 		Buffer		buf = buffers[i];
 		BufferDesc *buf_hdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		buf_state |= BM_VALID;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 
 	*extended_by = extend_by;
@@ -492,7 +492,7 @@ MarkLocalBufferDirty(Buffer buffer)
 {
 	int			bufid;
 	BufferDesc *bufHdr;
-	uint32		buf_state;
+	uint64		buf_state;
 
 	Assert(BufferIsLocal(buffer));
 
@@ -506,14 +506,14 @@ MarkLocalBufferDirty(Buffer buffer)
 
 	bufHdr = GetLocalBufferDescriptor(bufid);
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	if (!(buf_state & BM_DIRTY))
 		pgBufferUsage.local_blks_dirtied++;
 
 	buf_state |= BM_DIRTY;
 
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -522,7 +522,7 @@ MarkLocalBufferDirty(Buffer buffer)
 bool
 StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 
 	/*
 	 * With AIO the buffer could have IO in progress, e.g. when there are two
@@ -542,7 +542,7 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
 	/* Once we get here, there is definitely no I/O active on this buffer */
 
 	/* Check if someone else already did the I/O */
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 	if (forInput ? (buf_state & BM_VALID) : !(buf_state & BM_DIRTY))
 	{
 		return false;
@@ -559,11 +559,11 @@ StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait)
  * Like TerminateBufferIO, but for local buffers
  */
 void
-TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bits,
+TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint64 set_flag_bits,
 					   bool release_aio)
 {
 	/* Only need to adjust flags */
-	uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+	uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/* BM_IO_IN_PROGRESS isn't currently used for local buffers */
 
@@ -582,7 +582,7 @@ TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty, uint32 set_flag_bit
 	}
 
 	buf_state |= set_flag_bits;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 
 	/* local buffers don't track IO using resowners */
 
@@ -606,7 +606,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 {
 	Buffer		buffer = BufferDescriptorGetBuffer(bufHdr);
 	int			bufid = -buffer - 1;
-	uint32		buf_state;
+	uint64		buf_state;
 	LocalBufferLookupEnt *hresult;
 
 	/*
@@ -622,7 +622,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 		Assert(!pgaio_wref_valid(&bufHdr->io_wref));
 	}
 
-	buf_state = pg_atomic_read_u32(&bufHdr->state);
+	buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 	/*
 	 * We need to test not just LocalRefCount[bufid] but also the BufferDesc
@@ -647,7 +647,7 @@ InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced)
 	ClearBufferTag(&bufHdr->tag);
 	buf_state &= ~BUF_FLAG_MASK;
 	buf_state &= ~BUF_USAGECOUNT_MASK;
-	pg_atomic_unlocked_write_u32(&bufHdr->state, buf_state);
+	pg_atomic_unlocked_write_u64(&bufHdr->state, buf_state);
 }
 
 /*
@@ -671,9 +671,9 @@ DropRelationLocalBuffers(RelFileLocator rlocator, ForkNumber *forkNum,
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (!(buf_state & BM_TAG_VALID) ||
 			!BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -706,9 +706,9 @@ DropRelationAllLocalBuffers(RelFileLocator rlocator)
 	for (i = 0; i < NLocBuffer; i++)
 	{
 		BufferDesc *bufHdr = GetLocalBufferDescriptor(i);
-		uint32		buf_state;
+		uint64		buf_state;
 
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if ((buf_state & BM_TAG_VALID) &&
 			BufTagMatchesRelFileLocator(&bufHdr->tag, &rlocator))
@@ -804,11 +804,11 @@ InitLocalBuffers(void)
 bool
 PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 {
-	uint32		buf_state;
+	uint64		buf_state;
 	Buffer		buffer = BufferDescriptorGetBuffer(buf_hdr);
 	int			bufid = -buffer - 1;
 
-	buf_state = pg_atomic_read_u32(&buf_hdr->state);
+	buf_state = pg_atomic_read_u64(&buf_hdr->state);
 
 	if (LocalRefCount[bufid] == 0)
 	{
@@ -819,7 +819,7 @@ PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount)
 		{
 			buf_state += BUF_USAGECOUNT_ONE;
 		}
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/*
 		 * See comment in PinBuffer().
@@ -856,14 +856,14 @@ UnpinLocalBufferNoOwner(Buffer buffer)
 	if (--LocalRefCount[buffid] == 0)
 	{
 		BufferDesc *buf_hdr = GetLocalBufferDescriptor(buffid);
-		uint32		buf_state;
+		uint64		buf_state;
 
 		NLocalPinnedBuffers--;
 
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 		Assert(BUF_STATE_GET_REFCOUNT(buf_state) > 0);
 		buf_state -= BUF_REFCOUNT_ONE;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 
 		/* see comment in UnpinBufferNoOwner */
 		VALGRIND_MAKE_MEM_NOACCESS(LocalBufHdrGetBlock(buf_hdr), BLCKSZ);
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index b682dca658b..dcba3fb5473 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -199,7 +199,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 		for (i = 0; i < NBuffers; i++)
 		{
 			BufferDesc *bufHdr;
-			uint32		buf_state;
+			uint64		buf_state;
 
 			CHECK_FOR_INTERRUPTS();
 
@@ -615,7 +615,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr;
-		uint32		buf_state;
+		uint64		buf_state;
 
 		CHECK_FOR_INTERRUPTS();
 
@@ -626,7 +626,7 @@ pg_buffercache_summary(PG_FUNCTION_ARGS)
 		 * noticeably increase the cost of the function.
 		 */
 		bufHdr = GetBufferDescriptor(i);
-		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		buf_state = pg_atomic_read_u64(&bufHdr->state);
 
 		if (buf_state & BM_VALID)
 		{
@@ -676,7 +676,7 @@ pg_buffercache_usage_counts(PG_FUNCTION_ARGS)
 	for (int i = 0; i < NBuffers; i++)
 	{
 		BufferDesc *bufHdr = GetBufferDescriptor(i);
-		uint32		buf_state = pg_atomic_read_u32(&bufHdr->state);
+		uint64		buf_state = pg_atomic_read_u64(&bufHdr->state);
 		int			usage_count;
 
 		CHECK_FOR_INTERRUPTS();
diff --git a/contrib/pg_prewarm/autoprewarm.c b/contrib/pg_prewarm/autoprewarm.c
index 3ca7d2ed772..89e187425cc 100644
--- a/contrib/pg_prewarm/autoprewarm.c
+++ b/contrib/pg_prewarm/autoprewarm.c
@@ -703,7 +703,7 @@ apw_dump_now(bool is_bgworker, bool dump_unlogged)
 
 	for (num_blocks = 0, i = 0; i < NBuffers; i++)
 	{
-		uint32		buf_state;
+		uint64		buf_state;
 
 		CHECK_FOR_INTERRUPTS();
 
diff --git a/src/test/modules/test_aio/test_aio.c b/src/test/modules/test_aio/test_aio.c
index e046b08f3d5..b1aa8af9ec0 100644
--- a/src/test/modules/test_aio/test_aio.c
+++ b/src/test/modules/test_aio/test_aio.c
@@ -308,9 +308,9 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 {
 	Buffer		buf;
 	BufferDesc *buf_hdr;
-	uint32		buf_state;
+	uint64		buf_state;
 	bool		was_pinned = false;
-	uint32		unset_bits = 0;
+	uint64		unset_bits = 0;
 
 	/* place buffer in shared buffers without erroring out */
 	buf = ReadBufferExtended(rel, MAIN_FORKNUM, blkno, RBM_ZERO_AND_LOCK, NULL);
@@ -319,7 +319,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_hdr = GetLocalBufferDescriptor(-buf - 1);
-		buf_state = pg_atomic_read_u32(&buf_hdr->state);
+		buf_state = pg_atomic_read_u64(&buf_hdr->state);
 	}
 	else
 	{
@@ -340,7 +340,7 @@ create_toy_buffer(Relation rel, BlockNumber blkno)
 	if (RelationUsesLocalBuffers(rel))
 	{
 		buf_state &= ~unset_bits;
-		pg_atomic_unlocked_write_u32(&buf_hdr->state, buf_state);
+		pg_atomic_unlocked_write_u64(&buf_hdr->state, buf_state);
 	}
 	else
 	{
@@ -489,7 +489,7 @@ invalidate_rel_block(PG_FUNCTION_ARGS)
 
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 
-			if (pg_atomic_read_u32(&buf_hdr->state) & BM_DIRTY)
+			if (pg_atomic_read_u64(&buf_hdr->state) & BM_DIRTY)
 			{
 				if (BufferIsLocal(buf))
 					FlushLocalBuffer(buf_hdr, NULL);
@@ -572,7 +572,7 @@ buffer_call_terminate_io(PG_FUNCTION_ARGS)
 	bool		io_error = PG_GETARG_BOOL(3);
 	bool		release_aio = PG_GETARG_BOOL(4);
 	bool		clear_dirty = false;
-	uint32		set_flag_bits = 0;
+	uint64		set_flag_bits = 0;
 
 	if (io_error)
 		set_flag_bits |= BM_IO_ERROR;
-- 
2.48.1.76.g4e746b1a31.dirty


--c6wqr3sg4llxfu2u
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v11-0002-bufmgr-Implement-buffer-content-locks-independen.patch"



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end of thread, other threads:[~2026-01-14 01:10 UTC | newest]

Thread overview: 7+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2025-11-04 13:52 [PATCH v10 2/2] handle relation statistics correctly during rewrites Bertrand Drouvot <[email protected]>
2025-11-06 00:22 [PATCH v6 04/14] bufmgr: Change BufferDesc.state to be a 64bit atomic Andres Freund <[email protected]>
2025-12-02 23:46 [PATCH v7 11/15] bufmgr: Change BufferDesc.state to be a 64bit atomic Andres Freund <[email protected]>
2025-12-18 23:28 [PATCH v8 06/10] bufmgr: Change BufferDesc.state to be a 64bit atomic Andres Freund <[email protected]>
2026-01-07 22:26 [PATCH v9 06/10] bufmgr: Change BufferDesc.state to be a 64bit atomic Andres Freund <[email protected]>
2026-01-07 22:26 [PATCH v10 3/8] bufmgr: Change BufferDesc.state to be a 64-bit atomic Andres Freund <[email protected]>
2026-01-14 01:10 [PATCH v11 1/7] bufmgr: Change BufferDesc.state to be a 64-bit atomic Andres Freund <[email protected]>

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