v3-0001-Fix-to-report-wait-events-about-timeline-history-.patch

From 976a796c1ff7ed191d9f3df6c1111a333e700e3a Mon Sep 17 00:00:00 2001
From: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Date: Fri, 1 May 2020 09:38:51 +0900
Subject: [PATCH v3] 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 | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/backend/access/transam/timeline.c b/src/backend/access/transam/timeline.c
index de57d699af..4dfe9fddd1 100644
--- a/src/backend/access/transam/timeline.c
+++ b/src/backend/access/transam/timeline.c
@@ -123,7 +123,7 @@ readTimeLineHistory(TimeLineID targetTLI)
 	 * Parse the file...
 	 */
 	prevend = InvalidXLogRecPtr;
-	while (fgets(fline, sizeof(fline), fd) != NULL)
+	for (;;)
 	{
 		/* skip leading whitespace and check for # comment */
 		char	   *ptr;
@@ -132,6 +132,17 @@ readTimeLineHistory(TimeLineID targetTLI)
 		uint32		switchpoint_lo;
 		int			nfields;
 
+		pgstat_report_wait_start(WAIT_EVENT_TIMELINE_HISTORY_READ);
+		fgets(fline, sizeof(fline), fd);
+		pgstat_report_wait_end();
+
+		if (feof(fd))
+			break;
+		else if (ferror(fd))
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", path)));
+
 		for (ptr = fline; *ptr; ptr++)
 		{
 			if (!isspace((unsigned char) *ptr))
@@ -393,6 +404,7 @@ 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 +420,7 @@ 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)
-- 
2.25.1