0003-Use-pg_fstat_size-in-walsender.c.patch

From 252bbc8f88f980d977b721d157af74f7c2e8e83a Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Tue, 11 Feb 2020 17:10:25 +1300
Subject: [PATCH 3/3] Use pg_fstat_size() in walsender.c.

This replaces couple of lseek() calls.
---
 src/backend/replication/walsender.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index abb533b9d0..b94304a0e9 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -487,15 +487,11 @@ SendTimeLineHistory(TimeLineHistoryCmd *cmd)
 				 errmsg("could not open file \"%s\": %m", path)));
 
 	/* Determine file length and send it to client */
-	histfilelen = lseek(fd, 0, SEEK_END);
+	histfilelen = pg_fstat_size(fd);
 	if (histfilelen < 0)
 		ereport(ERROR,
 				(errcode_for_file_access(),
-				 errmsg("could not seek to end of file \"%s\": %m", path)));
-	if (lseek(fd, 0, SEEK_SET) != 0)
-		ereport(ERROR,
-				(errcode_for_file_access(),
-				 errmsg("could not seek to beginning of file \"%s\": %m", path)));
+				 errmsg("could not fstat file \"%s\": %m", path)));
 
 	pq_sendint32(&buf, histfilelen);	/* col2 len */
 
-- 
2.23.0