v18-0007-Remove-superfluous-bgwriter-stats.patch

From baae117915069f3807c67c98b649dbeab71fc47c Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Wed, 24 Nov 2021 12:20:10 -0500
Subject: [PATCH v18 7/8] Remove superfluous bgwriter stats

Remove stats from pg_stat_bgwriter which are now more clearly expressed
in pg_stat_buffers. Rename pg_stat_bgwriter to pg_stat_checkpointer
since most of the stats now concern checkpointer.

TODO:
- make pg_stat_bgwriter view again and move maxwritten_clean into it
- add additional stats to pg_stat_bgwriter
---
 doc/src/sgml/monitoring.sgml          | 69 +++++----------------------
 src/backend/catalog/system_views.sql  | 11 ++---
 src/backend/postmaster/checkpointer.c | 29 +----------
 src/backend/postmaster/pgstat.c       | 13 ++---
 src/backend/storage/buffer/bufmgr.c   |  6 ---
 src/backend/utils/adt/pgstatfuncs.c   | 34 +------------
 src/include/catalog/pg_proc.dat       | 34 +++----------
 src/include/pgstat.h                  | 12 +----
 src/test/regress/expected/rules.out   | 17 +++----
 9 files changed, 35 insertions(+), 190 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index b16952d439..412f0d2502 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -427,11 +427,11 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
      </row>
 
      <row>
-      <entry><structname>pg_stat_bgwriter</structname><indexterm><primary>pg_stat_bgwriter</primary></indexterm></entry>
+      <entry><structname>pg_stat_checkpointer</structname><indexterm><primary>pg_stat_checkpointer</primary></indexterm></entry>
       <entry>One row only, showing statistics about the
        background writer process's activity. See
-       <link linkend="monitoring-pg-stat-bgwriter-view">
-       <structname>pg_stat_bgwriter</structname></link> for details.
+       <link linkend="monitoring-pg-stat-checkpointer-view">
+       <structname>pg_stat_checkpointer</structname></link> for details.
      </entry>
      </row>
 
@@ -3485,20 +3485,20 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
 
  </sect2>
 
- <sect2 id="monitoring-pg-stat-bgwriter-view">
-  <title><structname>pg_stat_bgwriter</structname></title>
+ <sect2 id="monitoring-pg-stat-checkpointer-view">
+  <title><structname>pg_stat_checkpointer</structname></title>
 
   <indexterm>
-   <primary>pg_stat_bgwriter</primary>
+   <primary>pg_stat_checkpointer</primary>
   </indexterm>
 
   <para>
-   The <structname>pg_stat_bgwriter</structname> view will always have a
+   The <structname>pg_stat_checkpointer</structname> view will always have a
    single row, containing global data for the cluster.
   </para>
 
-  <table id="pg-stat-bgwriter-view" xreflabel="pg_stat_bgwriter">
-   <title><structname>pg_stat_bgwriter</structname> View</title>
+  <table id="pg-stat-checkpointer-view" xreflabel="pg_stat_checkpointer">
+   <title><structname>pg_stat_checkpointer</structname> View</title>
    <tgroup cols="1">
     <thead>
      <row>
@@ -3551,24 +3551,6 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
       </para></entry>
      </row>
 
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>buffers_checkpoint</structfield> <type>bigint</type>
-      </para>
-      <para>
-       Number of buffers written during checkpoints
-      </para></entry>
-     </row>
-
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>buffers_clean</structfield> <type>bigint</type>
-      </para>
-      <para>
-       Number of buffers written by the background writer
-      </para></entry>
-     </row>
-
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>maxwritten_clean</structfield> <type>bigint</type>
@@ -3579,35 +3561,6 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
       </para></entry>
      </row>
 
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>buffers_backend</structfield> <type>bigint</type>
-      </para>
-      <para>
-       Number of buffers written directly by a backend
-      </para></entry>
-     </row>
-
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>buffers_backend_fsync</structfield> <type>bigint</type>
-      </para>
-      <para>
-       Number of times a backend had to execute its own
-       <function>fsync</function> call (normally the background writer handles those
-       even when the backend does its own write)
-      </para></entry>
-     </row>
-
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>buffers_alloc</structfield> <type>bigint</type>
-      </para>
-      <para>
-       Number of buffers allocated
-      </para></entry>
-     </row>
-
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stats_reset</structfield> <type>timestamp with time zone</type>
@@ -5313,9 +5266,9 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
        </para>
        <para>
         Resets some cluster-wide statistics counters to zero, depending on the
-        argument.  The argument can be <literal>bgwriter</literal> to reset
+        argument.  The argument can be <literal>checkpointer</literal> to reset
         all the counters shown in
-        the <structname>pg_stat_bgwriter</structname>
+        the <structname>pg_stat_checkpointer</structname>
         view, <literal>archiver</literal> to reset all the counters shown in
         the <structname>pg_stat_archiver</structname> view, <literal>wal</literal>
         to reset all the counters shown in the <structname>pg_stat_wal</structname> view, 
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index e214d23056..6258c2770c 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1062,18 +1062,13 @@ CREATE VIEW pg_stat_archiver AS
         s.stats_reset
     FROM pg_stat_get_archiver() s;
 
-CREATE VIEW pg_stat_bgwriter AS
+CREATE VIEW pg_stat_checkpointer AS
     SELECT
-        pg_stat_get_bgwriter_timed_checkpoints() AS checkpoints_timed,
-        pg_stat_get_bgwriter_requested_checkpoints() AS checkpoints_req,
+        pg_stat_get_timed_checkpoints() AS checkpoints_timed,
+        pg_stat_get_requested_checkpoints() AS checkpoints_req,
         pg_stat_get_checkpoint_write_time() AS checkpoint_write_time,
         pg_stat_get_checkpoint_sync_time() AS checkpoint_sync_time,
-        pg_stat_get_bgwriter_buf_written_checkpoints() AS buffers_checkpoint,
-        pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean,
         pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean,
-        pg_stat_get_buf_written_backend() AS buffers_backend,
-        pg_stat_get_buf_fsync_backend() AS buffers_backend_fsync,
-        pg_stat_get_buf_alloc() AS buffers_alloc,
         pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 
 CREATE VIEW pg_stat_buffers AS
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index 8440b2b802..b9c3745474 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -90,17 +90,9 @@
  * requesting backends since the last checkpoint start.  The flags are
  * chosen so that OR'ing is the correct way to combine multiple requests.
  *
- * num_backend_writes is used to count the number of buffer writes performed
- * by user backend processes.  This counter should be wide enough that it
- * can't overflow during a single processing cycle.  num_backend_fsync
- * counts the subset of those writes that also had to do their own fsync,
- * because the checkpointer failed to absorb their request.
- *
  * The requests array holds fsync requests sent by backends and not yet
  * absorbed by the checkpointer.
  *
- * Unlike the checkpoint fields, num_backend_writes, num_backend_fsync, and
- * the requests fields are protected by CheckpointerCommLock.
  *----------
  */
 typedef struct
@@ -124,9 +116,6 @@ typedef struct
 	ConditionVariable start_cv; /* signaled when ckpt_started advances */
 	ConditionVariable done_cv;	/* signaled when ckpt_done advances */
 
-	uint32		num_backend_writes; /* counts user backend buffer writes */
-	uint32		num_backend_fsync;	/* counts user backend fsync calls */
-
 	int			num_requests;	/* current # of requests */
 	int			max_requests;	/* allocated array size */
 	CheckpointerRequest requests[FLEXIBLE_ARRAY_MEMBER];
@@ -1081,10 +1070,6 @@ ForwardSyncRequest(const FileTag *ftag, SyncRequestType type)
 
 	LWLockAcquire(CheckpointerCommLock, LW_EXCLUSIVE);
 
-	/* Count all backend writes regardless of if they fit in the queue */
-	if (!AmBackgroundWriterProcess())
-		CheckpointerShmem->num_backend_writes++;
-
 	/*
 	 * If the checkpointer isn't running or the request queue is full, the
 	 * backend will have to perform its own fsync request.  But before forcing
@@ -1094,13 +1079,12 @@ ForwardSyncRequest(const FileTag *ftag, SyncRequestType type)
 		(CheckpointerShmem->num_requests >= CheckpointerShmem->max_requests &&
 		 !CompactCheckpointerRequestQueue()))
 	{
+		LWLockRelease(CheckpointerCommLock);
+
 		/*
 		 * Count the subset of writes where backends have to do their own
 		 * fsync
 		 */
-		if (!AmBackgroundWriterProcess())
-			CheckpointerShmem->num_backend_fsync++;
-		LWLockRelease(CheckpointerCommLock);
 		pgstat_inc_ioop(IOOP_FSYNC, IOPATH_SHARED);
 		return false;
 	}
@@ -1257,15 +1241,6 @@ AbsorbSyncRequests(void)
 
 	LWLockAcquire(CheckpointerCommLock, LW_EXCLUSIVE);
 
-	/* Transfer stats counts into pending pgstats message */
-	PendingCheckpointerStats.m_buf_written_backend
-		+= CheckpointerShmem->num_backend_writes;
-	PendingCheckpointerStats.m_buf_fsync_backend
-		+= CheckpointerShmem->num_backend_fsync;
-
-	CheckpointerShmem->num_backend_writes = 0;
-	CheckpointerShmem->num_backend_fsync = 0;
-
 	/*
 	 * We try to avoid holding the lock for a long time by copying the request
 	 * array, and processing the requests after releasing the lock.
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 3545e197ce..13e46f497f 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -1601,8 +1601,8 @@ pgstat_reset_shared_counters(const char *target)
 	}
 	else if (strcmp(target, "archiver") == 0)
 		msg.m_resettarget = RESET_ARCHIVER;
-	else if (strcmp(target, "bgwriter") == 0)
-		msg.m_resettarget = RESET_BGWRITER;
+	else if (strcmp(target, "checkpointer") == 0)
+		msg.m_resettarget = RESET_CHECKPOINTER;
 	else if (strcmp(target, "wal") == 0)
 		msg.m_resettarget = RESET_WAL;
 	else
@@ -1610,7 +1610,7 @@ pgstat_reset_shared_counters(const char *target)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("unrecognized reset target: \"%s\"", target),
 				 errhint(
-					 "Target must be \"archiver\", \"bgwriter\", \"buffers\", or \"wal\".")));
+					 "Target must be \"archiver\", \"checkpointer\", \"buffers\", or \"wal\".")));
 
 
 	pgstat_send(&msg, sizeof(msg));
@@ -5679,7 +5679,7 @@ pgstat_recv_resetcounter(PgStat_MsgResetcounter *msg, int len)
 static void
 pgstat_recv_resetsharedcounter(PgStat_MsgResetsharedcounter *msg, int len)
 {
-	if (msg->m_resettarget == RESET_BGWRITER)
+	if (msg->m_resettarget == RESET_CHECKPOINTER)
 	{
 		/*
 		 * Reset the global bgwriter and checkpointer statistics for the
@@ -5985,9 +5985,7 @@ pgstat_recv_archiver(PgStat_MsgArchiver *msg, int len)
 static void
 pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len)
 {
-	globalStats.bgwriter.buf_written_clean += msg->m_buf_written_clean;
 	globalStats.bgwriter.maxwritten_clean += msg->m_maxwritten_clean;
-	globalStats.bgwriter.buf_alloc += msg->m_buf_alloc;
 }
 
 /* ----------
@@ -6003,9 +6001,6 @@ pgstat_recv_checkpointer(PgStat_MsgCheckpointer *msg, int len)
 	globalStats.checkpointer.requested_checkpoints += msg->m_requested_checkpoints;
 	globalStats.checkpointer.checkpoint_write_time += msg->m_checkpoint_write_time;
 	globalStats.checkpointer.checkpoint_sync_time += msg->m_checkpoint_sync_time;
-	globalStats.checkpointer.buf_written_checkpoints += msg->m_buf_written_checkpoints;
-	globalStats.checkpointer.buf_written_backend += msg->m_buf_written_backend;
-	globalStats.checkpointer.buf_fsync_backend += msg->m_buf_fsync_backend;
 }
 
 static void
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 949f1088b6..8120567de1 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -2164,7 +2164,6 @@ BufferSync(int flags)
 			if (SyncOneBuffer(buf_id, false, &wb_context) & BUF_WRITTEN)
 			{
 				TRACE_POSTGRESQL_BUFFER_SYNC_WRITTEN(buf_id);
-				PendingCheckpointerStats.m_buf_written_checkpoints++;
 				num_written++;
 			}
 		}
@@ -2273,9 +2272,6 @@ BgBufferSync(WritebackContext *wb_context)
 	 */
 	strategy_buf_id = StrategySyncStart(&strategy_passes, &recent_alloc);
 
-	/* Report buffer alloc counts to pgstat */
-	PendingBgWriterStats.m_buf_alloc += recent_alloc;
-
 	/*
 	 * If we're not running the LRU scan, just stop after doing the stats
 	 * stuff.  We mark the saved state invalid so that we can recover sanely
@@ -2472,8 +2468,6 @@ BgBufferSync(WritebackContext *wb_context)
 			reusable_buffers++;
 	}
 
-	PendingBgWriterStats.m_buf_written_clean += num_written;
-
 #ifdef BGW_DEBUG
 	elog(DEBUG1, "bgwriter: recent_alloc=%u smoothed=%.2f delta=%ld ahead=%d density=%.2f reusable_est=%d upcoming_est=%d scanned=%d wrote=%d reusable=%d",
 		 recent_alloc, smoothed_alloc, strategy_delta, bufs_ahead,
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 26730230b6..52500c8af4 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -1727,29 +1727,17 @@ pg_stat_get_db_sessions_killed(PG_FUNCTION_ARGS)
 }
 
 Datum
-pg_stat_get_bgwriter_timed_checkpoints(PG_FUNCTION_ARGS)
+pg_stat_get_timed_checkpoints(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->timed_checkpoints);
 }
 
 Datum
-pg_stat_get_bgwriter_requested_checkpoints(PG_FUNCTION_ARGS)
+pg_stat_get_requested_checkpoints(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->requested_checkpoints);
 }
 
-Datum
-pg_stat_get_bgwriter_buf_written_checkpoints(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->buf_written_checkpoints);
-}
-
-Datum
-pg_stat_get_bgwriter_buf_written_clean(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_INT64(pgstat_fetch_stat_bgwriter()->buf_written_clean);
-}
-
 Datum
 pg_stat_get_bgwriter_maxwritten_clean(PG_FUNCTION_ARGS)
 {
@@ -1778,24 +1766,6 @@ pg_stat_get_bgwriter_stat_reset_time(PG_FUNCTION_ARGS)
 	PG_RETURN_TIMESTAMPTZ(pgstat_fetch_stat_bgwriter()->stat_reset_timestamp);
 }
 
-Datum
-pg_stat_get_buf_written_backend(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->buf_written_backend);
-}
-
-Datum
-pg_stat_get_buf_fsync_backend(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_INT64(pgstat_fetch_stat_checkpointer()->buf_fsync_backend);
-}
-
-Datum
-pg_stat_get_buf_alloc(PG_FUNCTION_ARGS)
-{
-	PG_RETURN_INT64(pgstat_fetch_stat_bgwriter()->buf_alloc);
-}
-
 /*
 * When adding a new column to the pg_stat_buffers view, add a new enum
 * value here above BUFFERS_NUM_COLUMNS.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 148208d242..293df23040 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -5585,25 +5585,15 @@
   proargnames => '{archived_count,last_archived_wal,last_archived_time,failed_count,last_failed_wal,last_failed_time,stats_reset}',
   prosrc => 'pg_stat_get_archiver' },
 { oid => '2769',
-  descr => 'statistics: number of timed checkpoints started by the bgwriter',
-  proname => 'pg_stat_get_bgwriter_timed_checkpoints', provolatile => 's',
+  descr => 'statistics: number of scheduled checkpoints performed',
+  proname => 'pg_stat_get_timed_checkpoints', provolatile => 's',
   proparallel => 'r', prorettype => 'int8', proargtypes => '',
-  prosrc => 'pg_stat_get_bgwriter_timed_checkpoints' },
+  prosrc => 'pg_stat_get_timed_checkpoints' },
 { oid => '2770',
-  descr => 'statistics: number of backend requested checkpoints started by the bgwriter',
-  proname => 'pg_stat_get_bgwriter_requested_checkpoints', provolatile => 's',
+  descr => 'statistics: number of backend requested checkpoints performed',
+  proname => 'pg_stat_get_requested_checkpoints', provolatile => 's',
   proparallel => 'r', prorettype => 'int8', proargtypes => '',
-  prosrc => 'pg_stat_get_bgwriter_requested_checkpoints' },
-{ oid => '2771',
-  descr => 'statistics: number of buffers written by the bgwriter during checkpoints',
-  proname => 'pg_stat_get_bgwriter_buf_written_checkpoints', provolatile => 's',
-  proparallel => 'r', prorettype => 'int8', proargtypes => '',
-  prosrc => 'pg_stat_get_bgwriter_buf_written_checkpoints' },
-{ oid => '2772',
-  descr => 'statistics: number of buffers written by the bgwriter for cleaning dirty buffers',
-  proname => 'pg_stat_get_bgwriter_buf_written_clean', provolatile => 's',
-  proparallel => 'r', prorettype => 'int8', proargtypes => '',
-  prosrc => 'pg_stat_get_bgwriter_buf_written_clean' },
+  prosrc => 'pg_stat_get_requested_checkpoints' },
 { oid => '2773',
   descr => 'statistics: number of times the bgwriter stopped processing when it had written too many buffers while cleaning',
   proname => 'pg_stat_get_bgwriter_maxwritten_clean', provolatile => 's',
@@ -5623,18 +5613,6 @@
   proname => 'pg_stat_get_checkpoint_sync_time', provolatile => 's',
   proparallel => 'r', prorettype => 'float8', proargtypes => '',
   prosrc => 'pg_stat_get_checkpoint_sync_time' },
-{ oid => '2775', descr => 'statistics: number of buffers written by backends',
-  proname => 'pg_stat_get_buf_written_backend', provolatile => 's',
-  proparallel => 'r', prorettype => 'int8', proargtypes => '',
-  prosrc => 'pg_stat_get_buf_written_backend' },
-{ oid => '3063',
-  descr => 'statistics: number of backend buffer writes that did their own fsync',
-  proname => 'pg_stat_get_buf_fsync_backend', provolatile => 's',
-  proparallel => 'r', prorettype => 'int8', proargtypes => '',
-  prosrc => 'pg_stat_get_buf_fsync_backend' },
-{ oid => '2859', descr => 'statistics: number of buffer allocations',
-  proname => 'pg_stat_get_buf_alloc', provolatile => 's', proparallel => 'r',
-  prorettype => 'int8', proargtypes => '', prosrc => 'pg_stat_get_buf_alloc' },
 
 { oid => '8459', descr => 'statistics: counts of all IO operations done to all IO paths by each type of backend.',
   proname => 'pg_stat_get_buffers', provolatile => 's', proisstrict => 'f',
diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index 8e07584767..020cd4ca87 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -141,7 +141,7 @@ typedef struct PgStat_TableCounts
 typedef enum PgStat_Shared_Reset_Target
 {
 	RESET_ARCHIVER,
-	RESET_BGWRITER,
+	RESET_CHECKPOINTER,
 	RESET_BUFFERS,
 	RESET_WAL
 } PgStat_Shared_Reset_Target;
@@ -523,9 +523,7 @@ typedef struct PgStat_MsgBgWriter
 {
 	PgStat_MsgHdr m_hdr;
 
-	PgStat_Counter m_buf_written_clean;
 	PgStat_Counter m_maxwritten_clean;
-	PgStat_Counter m_buf_alloc;
 } PgStat_MsgBgWriter;
 
 /* ----------
@@ -538,9 +536,6 @@ typedef struct PgStat_MsgCheckpointer
 
 	PgStat_Counter m_timed_checkpoints;
 	PgStat_Counter m_requested_checkpoints;
-	PgStat_Counter m_buf_written_checkpoints;
-	PgStat_Counter m_buf_written_backend;
-	PgStat_Counter m_buf_fsync_backend;
 	PgStat_Counter m_checkpoint_write_time; /* times in milliseconds */
 	PgStat_Counter m_checkpoint_sync_time;
 } PgStat_MsgCheckpointer;
@@ -971,9 +966,7 @@ typedef struct PgStat_ArchiverStats
  */
 typedef struct PgStat_BgWriterStats
 {
-	PgStat_Counter buf_written_clean;
 	PgStat_Counter maxwritten_clean;
-	PgStat_Counter buf_alloc;
 	TimestampTz stat_reset_timestamp;
 } PgStat_BgWriterStats;
 
@@ -987,9 +980,6 @@ typedef struct PgStat_CheckpointerStats
 	PgStat_Counter requested_checkpoints;
 	PgStat_Counter checkpoint_write_time;	/* times in milliseconds */
 	PgStat_Counter checkpoint_sync_time;
-	PgStat_Counter buf_written_checkpoints;
-	PgStat_Counter buf_written_backend;
-	PgStat_Counter buf_fsync_backend;
 } PgStat_CheckpointerStats;
 
 /*
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 5869ce442f..13f48722c3 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1817,17 +1817,6 @@ pg_stat_archiver| SELECT s.archived_count,
     s.last_failed_time,
     s.stats_reset
    FROM pg_stat_get_archiver() s(archived_count, last_archived_wal, last_archived_time, failed_count, last_failed_wal, last_failed_time, stats_reset);
-pg_stat_bgwriter| SELECT pg_stat_get_bgwriter_timed_checkpoints() AS checkpoints_timed,
-    pg_stat_get_bgwriter_requested_checkpoints() AS checkpoints_req,
-    pg_stat_get_checkpoint_write_time() AS checkpoint_write_time,
-    pg_stat_get_checkpoint_sync_time() AS checkpoint_sync_time,
-    pg_stat_get_bgwriter_buf_written_checkpoints() AS buffers_checkpoint,
-    pg_stat_get_bgwriter_buf_written_clean() AS buffers_clean,
-    pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean,
-    pg_stat_get_buf_written_backend() AS buffers_backend,
-    pg_stat_get_buf_fsync_backend() AS buffers_backend_fsync,
-    pg_stat_get_buf_alloc() AS buffers_alloc,
-    pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 pg_stat_buffers| SELECT b.backend_type,
     b.io_path,
     b.alloc,
@@ -1836,6 +1825,12 @@ pg_stat_buffers| SELECT b.backend_type,
     b.write,
     b.stats_reset
    FROM pg_stat_get_buffers() b(backend_type, io_path, alloc, extend, fsync, write, stats_reset);
+pg_stat_checkpointer| SELECT pg_stat_get_timed_checkpoints() AS checkpoints_timed,
+    pg_stat_get_requested_checkpoints() AS checkpoints_req,
+    pg_stat_get_checkpoint_write_time() AS checkpoint_write_time,
+    pg_stat_get_checkpoint_sync_time() AS checkpoint_sync_time,
+    pg_stat_get_bgwriter_maxwritten_clean() AS maxwritten_clean,
+    pg_stat_get_bgwriter_stat_reset_time() AS stats_reset;
 pg_stat_database| SELECT d.oid AS datid,
     d.datname,
         CASE
-- 
2.30.2