From b175bd59fa54a90d21bc541f812643ac45281b98 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Tue, 7 Jan 2020 17:38:48 -0300 Subject: [PATCH] pg_stat_activity: show NULL stmt start time for walsenders Returning a non-NULL time is pointless, sinc a walsender is not a process that would be running normal transactions anyway, but the code was unintentionally exposing the process start time intermittently, which was not only bogus but it also confused monitoring systems looking for idle transactions. Fix by avoiding all updates in walsenders. Backpatch to 11, where walsenders started appearing in pg_stat_activity. Reported-by: Tomas Vondra Discussion: https://postgr.es/m/20191209234409.exe7osmyalwkt5j4@development --- src/backend/access/transam/xact.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index 017f03b6d8..cbc35454a7 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -816,6 +816,13 @@ GetCurrentTransactionStopTimestamp(void) void SetCurrentStatementStartTimestamp(void) { + /* + * Skip if on a walsender; this is not needed, and it confuses monitoring + * if we publish non-NULL values. + */ + if (am_walsender) + return; + if (!IsParallelWorker()) stmtStartTimestamp = GetCurrentTimestamp(); else