From e63bb4549a2f47b86de9fc21c9f8b00440f34f99 Mon Sep 17 00:00:00 2001
From: Simon Riggs <simon@2ndQuadrant.com>
Date: Tue, 12 Jan 2016 07:54:52 +0000
Subject: Add new user fn pg_current_xlog_flush_location()

Tomas Vondra, reviewed by Michael Paquier and Amit Kapila
Minor edits by me
---
 src/backend/access/transam/xlogfuncs.c | 21 +++++++++++++++++++++
 src/include/access/xlog_fn.h           |  1 +
 src/include/catalog/pg_proc.h          |  2 ++
 3 files changed, 24 insertions(+)

(limited to 'src')

diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 42168985e0c..31cbb01ce47 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -215,6 +215,27 @@ pg_current_xlog_insert_location(PG_FUNCTION_ARGS)
 	PG_RETURN_LSN(current_recptr);
 }
 
+/*
+ * Report the current WAL flush location (same format as pg_start_backup etc)
+ *
+ * This function is mostly for debugging purposes.
+ */
+Datum
+pg_current_xlog_flush_location(PG_FUNCTION_ARGS)
+{
+	XLogRecPtr	current_recptr;
+
+	if (RecoveryInProgress())
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("recovery is in progress"),
+				 errhint("WAL control functions cannot be executed during recovery.")));
+
+	current_recptr = GetFlushRecPtr();
+
+	PG_RETURN_LSN(current_recptr);
+}
+
 /*
  * Report the last WAL receive location (same format as pg_start_backup etc)
  *
diff --git a/src/include/access/xlog_fn.h b/src/include/access/xlog_fn.h
index 73046b0a4fa..762df8bea30 100644
--- a/src/include/access/xlog_fn.h
+++ b/src/include/access/xlog_fn.h
@@ -19,6 +19,7 @@ extern Datum pg_switch_xlog(PG_FUNCTION_ARGS);
 extern Datum pg_create_restore_point(PG_FUNCTION_ARGS);
 extern Datum pg_current_xlog_location(PG_FUNCTION_ARGS);
 extern Datum pg_current_xlog_insert_location(PG_FUNCTION_ARGS);
+extern Datum pg_current_xlog_flush_location(PG_FUNCTION_ARGS);
 extern Datum pg_last_xlog_receive_location(PG_FUNCTION_ARGS);
 extern Datum pg_last_xlog_replay_location(PG_FUNCTION_ARGS);
 extern Datum pg_last_xact_replay_timestamp(PG_FUNCTION_ARGS);
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 95d683c8ff5..f58672e4a7c 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3158,6 +3158,8 @@ DATA(insert OID = 2849 ( pg_current_xlog_location	PGNSP PGUID 12 1 0 0 0 f f f f
 DESCR("current xlog write location");
 DATA(insert OID = 2852 ( pg_current_xlog_insert_location	PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 3220 "" _null_ _null_ _null_ _null_ _null_ pg_current_xlog_insert_location _null_ _null_ _null_ ));
 DESCR("current xlog insert location");
+DATA(insert OID = 3330 ( pg_current_xlog_flush_location	PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 3220 "" _null_ _null_ _null_ _null_ _null_ pg_current_xlog_flush_location _null_ _null_ _null_ ));
+DESCR("current xlog flush location");
 DATA(insert OID = 2850 ( pg_xlogfile_name_offset	PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 2249 "3220" "{3220,25,23}" "{i,o,o}" "{wal_location,file_name,file_offset}" _null_ _null_ pg_xlogfile_name_offset _null_ _null_ _null_ ));
 DESCR("xlog filename and byte offset, given an xlog location");
 DATA(insert OID = 2851 ( pg_xlogfile_name			PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 25 "3220" _null_ _null_ _null_ _null_ _null_ pg_xlogfile_name _null_ _null_ _null_ ));
-- 
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