v2-0001-Fix-to-report-wait-events-about-timeline-history-.patch

From 20b6eb5bb7af574e4395f653917db5a54d13d7d5 Mon Sep 17 00:00:00 2001
From: Masahiro Ikeda <ikedamsh@nttdata.co.jp>
Date: Tue, 28 Apr 2020 01:39:25 +0000
Subject: [PATCH v2] Fix to report wait events about timeline history file.

Even though a timeline history file is read or written,
some wait events are not reported. This patch fixes those issues.
---
 src/backend/access/transam/timeline.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/backend/access/transam/timeline.c b/src/backend/access/transam/timeline.c
index de57d69..3e1b90f 100644
--- a/src/backend/access/transam/timeline.c
+++ b/src/backend/access/transam/timeline.c
@@ -123,8 +123,15 @@ readTimeLineHistory(TimeLineID targetTLI)
 	 * Parse the file...
 	 */
 	prevend = InvalidXLogRecPtr;
-	while (fgets(fline, sizeof(fline), fd) != NULL)
+	for (;;)
 	{
+		char	   *result;
+		pgstat_report_wait_start(WAIT_EVENT_TIMELINE_HISTORY_READ);
+		result = fgets(fline, sizeof(fline), fd);
+		pgstat_report_wait_end();
+		if (result == NULL)
+			break;
+
 		/* skip leading whitespace and check for # comment */
 		char	   *ptr;
 		TimeLineID	tli;
@@ -393,6 +400,7 @@ writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
 
 	nbytes = strlen(buffer);
 	errno = 0;
+	pgstat_report_wait_start(WAIT_EVENT_TIMELINE_HISTORY_WRITE);
 	if ((int) write(fd, buffer, nbytes) != nbytes)
 	{
 		int			save_errno = errno;
@@ -408,6 +416,7 @@ writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
 				(errcode_for_file_access(),
 				 errmsg("could not write to file \"%s\": %m", tmppath)));
 	}
+	pgstat_report_wait_end();
 
 	pgstat_report_wait_start(WAIT_EVENT_TIMELINE_HISTORY_SYNC);
 	if (pg_fsync(fd) != 0)
-- 
2.9.5