v3-0002-pg_prewarm-fix-autoprewarm_interval-behaviour.patch

From fba212ed765c8c411db1ca19c2ac991662109d99 Mon Sep 17 00:00:00 2001
From: Alexey Kondratov <kondratov.aleksey@gmail.com>
Date: Mon, 9 Nov 2020 19:12:00 +0300
Subject: [PATCH v3 2/3] pg_prewarm: fix autoprewarm_interval behaviour

Previously it misused seconds from TimestampDifference() as
milliseconds, so it was busy looping with ~1 second interval
instead of waiting on latch with default autoprewarm_interval = 300s.
---
 contrib/pg_prewarm/autoprewarm.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/contrib/pg_prewarm/autoprewarm.c b/contrib/pg_prewarm/autoprewarm.c
index d3dec6e3ec..e5bd130bc8 100644
--- a/contrib/pg_prewarm/autoprewarm.c
+++ b/contrib/pg_prewarm/autoprewarm.c
@@ -222,16 +222,14 @@ autoprewarm_main(Datum main_arg)
 		{
 			long		delay_in_ms = 0;
 			TimestampTz next_dump_time = 0;
-			long		secs = 0;
-			int			usecs = 0;
 
 			/* Compute the next dump time. */
 			next_dump_time =
 				TimestampTzPlusMilliseconds(last_dump_time,
 											autoprewarm_interval * 1000);
-			TimestampDifference(GetCurrentTimestamp(), next_dump_time,
-								&secs, &usecs);
-			delay_in_ms = secs + (usecs / 1000);
+			delay_in_ms =
+				TimestampDifferenceMilliseconds(GetCurrentTimestamp(),
+												next_dump_time);
 
 			/* Perform a dump if it's time. */
 			if (delay_in_ms <= 0)
-- 
2.19.1