Move LSN waiting declarations and definitions to better place

3c5db1d6b implemented the pg_wal_replay_wait() stored procedure.  Due to
the patch development history, the implementation resided in
src/backend/commands/waitlsn.c (src/include/commands/waitlsn.h for headers).

014f9f34d moved pg_wal_replay_wait() itself to
src/backend/access/transam/xlogfuncs.c near to the WAL-manipulation functions.
But most of the implementation stayed in place.

The code in src/backend/commands/waitlsn.c has nothing to do with commands,
but is related to WAL.  So, this commit moves this code into
src/backend/access/transam/xlogwait.c (src/include/access/xlogwait.h for
headers).

Reported-by: Peter Eisentraut
Discussion: https://postgr.es/m/18c0fa64-0475-415e-a1bd-665d922c5201%40eisentraut.org
Reviewed-by: Pavel Borisov

src/backend/access/transam/Makefile

@@ -36,7 +36,8 @@ OBJS = \
 	xlogreader.o \
 	xlogrecovery.o \
 	xlogstats.o \
-	xlogutils.o
+	xlogutils.o \
+	xlogwait.o
 
 include $(top_srcdir)/src/backend/common.mk
 

src/backend/access/transam/meson.build

@@ -24,6 +24,7 @@ backend_sources += files(
   'xlogrecovery.c',
   'xlogstats.c',
   'xlogutils.c',
+  'xlogwait.c',
 )
 
 # used by frontend programs to build a frontend xlogreader

src/backend/access/transam/xact.c

@@ -31,6 +31,7 @@
 #include "access/xloginsert.h"
 #include "access/xlogrecovery.h"
 #include "access/xlogutils.h"
+#include "access/xlogwait.h"
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/pg_enum.h"
@@ -38,7 +39,6 @@
 #include "commands/async.h"
 #include "commands/tablecmds.h"
 #include "commands/trigger.h"
-#include "commands/waitlsn.h"
 #include "common/pg_prng.h"
 #include "executor/spi.h"
 #include "libpq/be-fsstubs.h"

src/backend/access/transam/xlog.c

@@ -62,11 +62,11 @@
 #include "access/xlogreader.h"
 #include "access/xlogrecovery.h"
 #include "access/xlogutils.h"
+#include "access/xlogwait.h"
 #include "backup/basebackup.h"
 #include "catalog/catversion.h"
 #include "catalog/pg_control.h"
 #include "catalog/pg_database.h"
-#include "commands/waitlsn.h"
 #include "common/controldata_utils.h"
 #include "common/file_utils.h"
 #include "executor/instrument.h"

src/backend/access/transam/xlogfuncs.c

@@ -22,8 +22,8 @@
 #include "access/xlog_internal.h"
 #include "access/xlogbackup.h"
 #include "access/xlogrecovery.h"
+#include "access/xlogwait.h"
 #include "catalog/pg_type.h"
-#include "commands/waitlsn.h"
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "pgstat.h"

src/backend/access/transam/xlogrecovery.c

@@ -40,10 +40,10 @@
 #include "access/xlogreader.h"
 #include "access/xlogrecovery.h"
 #include "access/xlogutils.h"
+#include "access/xlogwait.h"
 #include "backup/basebackup.h"
 #include "catalog/pg_control.h"
 #include "commands/tablespace.h"
-#include "commands/waitlsn.h"
 #include "common/file_utils.h"
 #include "miscadmin.h"
 #include "pgstat.h"

src/backend/access/transam/xlogwait.c

@@ -1,13 +1,13 @@
 /*-------------------------------------------------------------------------
  *
- * waitlsn.c
+ * xlogwait.c
  *	  Implements waiting for the given replay LSN, which is used in
  *	  CALL pg_wal_replay_wait(target_lsn pg_lsn, timeout float8).
  *
  * Copyright (c) 2024, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  src/backend/commands/waitlsn.c
+ *	  src/backend/access/transam/xlogwait.c
  *
  *-------------------------------------------------------------------------
  */
@@ -20,7 +20,7 @@
 #include "pgstat.h"
 #include "access/xlog.h"
 #include "access/xlogrecovery.h"
-#include "commands/waitlsn.h"
+#include "access/xlogwait.h"
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "storage/latch.h"

src/backend/commands/Makefile

@@ -61,7 +61,6 @@ OBJS = \
 	vacuum.o \
 	vacuumparallel.o \
 	variable.o \
-	view.o \
-	waitlsn.o
+	view.o
 
 include $(top_srcdir)/src/backend/common.mk

src/backend/commands/meson.build

@@ -50,5 +50,4 @@ backend_sources += files(
   'vacuumparallel.c',
   'variable.c',
   'view.c',
-  'waitlsn.c',
 )

src/backend/storage/ipc/ipci.c

@@ -24,8 +24,8 @@
 #include "access/twophase.h"
 #include "access/xlogprefetcher.h"
 #include "access/xlogrecovery.h"
+#include "access/xlogwait.h"
 #include "commands/async.h"
-#include "commands/waitlsn.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "postmaster/autovacuum.h"

src/backend/storage/lmgr/proc.c

@@ -36,7 +36,7 @@
 #include "access/transam.h"
 #include "access/twophase.h"
 #include "access/xlogutils.h"
-#include "commands/waitlsn.h"
+#include "access/xlogwait.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "postmaster/autovacuum.h"

src/include/access/xlogwait.h

@@ -1,16 +1,16 @@
 /*-------------------------------------------------------------------------
  *
- * waitlsn.h
+ * xlogwait.h
  *	  Declarations for LSN replay waiting routines.
  *
  * Copyright (c) 2024, PostgreSQL Global Development Group
  *
- * src/include/commands/waitlsn.h
+ * src/include/access/xlogwait.h
  *
  *-------------------------------------------------------------------------
  */
-#ifndef WAIT_LSN_H
-#define WAIT_LSN_H
+#ifndef XLOG_WAIT_H
+#define XLOG_WAIT_H
 
 #include "lib/pairingheap.h"
 #include "postgres.h"
@@ -78,4 +78,4 @@ extern void WaitLSNSetLatches(XLogRecPtr currentLSN);
 extern void WaitLSNCleanup(void);
 extern void WaitForLSNReplay(XLogRecPtr targetLSN, int64 timeout);
 
-#endif							/* WAIT_LSN_H */
+#endif							/* XLOG_WAIT_H */