0001-Revert-Add-redo-LSN-to-pgstats-files.patch

From dd72c59d7a7295262d080b063678f82e548bb50f Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Sat, 15 Mar 2025 10:55:41 +0900
Subject: [PATCH] Revert "Add redo LSN to pgstats files"

This reverts commit b860848232aab440c9ac4c5de3563565e3d2934b.
---
 src/include/pgstat.h                |  5 ++--
 src/backend/access/transam/xlog.c   |  2 +-
 src/backend/utils/activity/pgstat.c | 41 +++++++----------------------
 3 files changed, 12 insertions(+), 36 deletions(-)

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index def6b370ac11..b01875d5b165 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -11,7 +11,6 @@
 #ifndef PGSTAT_H
 #define PGSTAT_H
 
-#include "access/xlogdefs.h"
 #include "datatype/timestamp.h"
 #include "portability/instr_time.h"
 #include "postmaster/pgarch.h"	/* for MAX_XFN_CHARS */
@@ -212,7 +211,7 @@ typedef struct PgStat_TableXactStatus
  * ------------------------------------------------------------
  */
 
-#define PGSTAT_FILE_FORMAT_ID	0x01A5BCB5
+#define PGSTAT_FILE_FORMAT_ID	0x01A5BCB6
 
 typedef struct PgStat_ArchiverStats
 {
@@ -514,7 +513,7 @@ extern Size StatsShmemSize(void);
 extern void StatsShmemInit(void);
 
 /* Functions called during server startup / shutdown */
-extern void pgstat_restore_stats(XLogRecPtr redo);
+extern void pgstat_restore_stats(void);
 extern void pgstat_discard_stats(void);
 extern void pgstat_before_server_shutdown(int code, Datum arg);
 
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 799fc739e18c..4b6c694a3f71 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5728,7 +5728,7 @@ StartupXLOG(void)
 	if (didCrash)
 		pgstat_discard_stats();
 	else
-		pgstat_restore_stats(checkPoint.redo);
+		pgstat_restore_stats();
 
 	lastFullPageWrites = checkPoint.fullPageWrites;
 
diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c
index 3168b825e25f..40063085073f 100644
--- a/src/backend/utils/activity/pgstat.c
+++ b/src/backend/utils/activity/pgstat.c
@@ -104,7 +104,6 @@
 #include <unistd.h>
 
 #include "access/xact.h"
-#include "access/xlog.h"
 #include "lib/dshash.h"
 #include "pgstat.h"
 #include "storage/fd.h"
@@ -181,8 +180,8 @@ typedef struct PgStat_SnapshotEntry
  * ----------
  */
 
-static void pgstat_write_statsfile(XLogRecPtr redo);
-static void pgstat_read_statsfile(XLogRecPtr redo);
+static void pgstat_write_statsfile(void);
+static void pgstat_read_statsfile(void);
 
 static void pgstat_init_snapshot_fixed(void);
 
@@ -503,9 +502,9 @@ static const PgStat_KindInfo **pgstat_kind_custom_infos = NULL;
  * Should only be called by the startup process or in single user mode.
  */
 void
-pgstat_restore_stats(XLogRecPtr redo)
+pgstat_restore_stats(void)
 {
-	pgstat_read_statsfile(redo);
+	pgstat_read_statsfile();
 }
 
 /*
@@ -581,7 +580,7 @@ pgstat_before_server_shutdown(int code, Datum arg)
 	if (code == 0)
 	{
 		pgStatLocal.shmem->is_shutdown = true;
-		pgstat_write_statsfile(GetRedoRecPtr());
+		pgstat_write_statsfile();
 	}
 }
 
@@ -1585,7 +1584,7 @@ write_chunk(FILE *fpout, void *ptr, size_t len)
  * stats so locking is not required.
  */
 static void
-pgstat_write_statsfile(XLogRecPtr redo)
+pgstat_write_statsfile(void)
 {
 	FILE	   *fpout;
 	int32		format_id;
@@ -1602,8 +1601,7 @@ pgstat_write_statsfile(XLogRecPtr redo)
 	/* we're shutting down, so it's ok to just override this */
 	pgstat_fetch_consistency = PGSTAT_FETCH_CONSISTENCY_NONE;
 
-	elog(DEBUG2, "writing stats file \"%s\" with redo %X/%X", statfile,
-		 LSN_FORMAT_ARGS(redo));
+	elog(DEBUG2, "writing stats file \"%s\"", statfile);
 
 	/*
 	 * Open the statistics temp file to write out the current values.
@@ -1624,9 +1622,6 @@ pgstat_write_statsfile(XLogRecPtr redo)
 	format_id = PGSTAT_FILE_FORMAT_ID;
 	write_chunk_s(fpout, &format_id);
 
-	/* Write the redo LSN, used to cross check the file read */
-	write_chunk_s(fpout, &redo);
-
 	/* Write various stats structs for fixed number of objects */
 	for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++)
 	{
@@ -1773,20 +1768,18 @@ read_chunk(FILE *fpin, void *ptr, size_t len)
  * stats so locking is not required.
  */
 static void
-pgstat_read_statsfile(XLogRecPtr redo)
+pgstat_read_statsfile(void)
 {
 	FILE	   *fpin;
 	int32		format_id;
 	bool		found;
 	const char *statfile = PGSTAT_STAT_PERMANENT_FILENAME;
 	PgStat_ShmemControl *shmem = pgStatLocal.shmem;
-	XLogRecPtr	file_redo;
 
 	/* shouldn't be called from postmaster */
 	Assert(IsUnderPostmaster || !IsPostmasterEnvironment);
 
-	elog(DEBUG2, "reading stats file \"%s\" with redo %X/%X", statfile,
-		 LSN_FORMAT_ARGS(redo));
+	elog(DEBUG2, "reading stats file \"%s\"", statfile);
 
 	/*
 	 * Try to open the stats file. If it doesn't exist, the backends simply
@@ -1824,22 +1817,6 @@ pgstat_read_statsfile(XLogRecPtr redo)
 		goto error;
 	}
 
-	/*
-	 * Read the redo LSN stored in the file.
-	 */
-	if (!read_chunk_s(fpin, &file_redo))
-	{
-		elog(WARNING, "could not read redo LSN");
-		goto error;
-	}
-
-	if (file_redo != redo)
-	{
-		elog(WARNING, "found incorrect redo LSN %X/%X (expected %X/%X)",
-			 LSN_FORMAT_ARGS(file_redo), LSN_FORMAT_ARGS(redo));
-		goto error;
-	}
-
 	/*
 	 * We found an existing statistics file. Read it and put all the stats
 	 * data into place.
-- 
2.46.0