From 951820a8e312584f283ef4b5bde006c7f41e0d9d Mon Sep 17 00:00:00 2001 From: Laurenz Albe Date: Wed, 18 Aug 2021 04:52:57 +0200 Subject: [PATCH] Improve performance and accuracy of session statistics Rather than calling GetCurrentTimestamp() in pgstat_send_connstats(), which causes an additional system call, reuse the value just calculated in pgstat_report_stat(). Since the "now" value in pgstat_report_stat() will become the next "last_report" value, this will also improve the accuracy of the statistics, since the timestamp difference calculated in pgstat_send_connstats() will become the correct one. This patch does not address the issue that yet another UDP packet is sent to the statistics collector for session statistics. Discussion: https://postgr.es/m/20210801205501.nyxzxoelqoo4x2qc%40alap3.anarazel.de --- src/backend/postmaster/pgstat.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c index ce8888cc30..77d734a0ba 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -324,7 +324,7 @@ static void pgstat_send_tabstat(PgStat_MsgTabstat *tsmsg); static void pgstat_send_funcstats(void); static void pgstat_send_slru(void); static HTAB *pgstat_collect_oids(Oid catalogid, AttrNumber anum_oid); -static void pgstat_send_connstats(bool disconnect, TimestampTz last_report); +static void pgstat_send_connstats(bool disconnect, TimestampTz last_report, TimestampTz now); static PgStat_TableStatus *get_tabstat_entry(Oid rel_id, bool isshared); @@ -879,7 +879,7 @@ pgstat_report_stat(bool disconnect) /* for backends, send connection statistics */ if (MyBackendType == B_BACKEND) - pgstat_send_connstats(disconnect, last_report); + pgstat_send_connstats(disconnect, last_report, now); last_report = now; @@ -1375,7 +1375,7 @@ pgstat_drop_relation(Oid relid) * ---------- */ static void -pgstat_send_connstats(bool disconnect, TimestampTz last_report) +pgstat_send_connstats(bool disconnect, TimestampTz last_report, TimestampTz now) { PgStat_MsgConn msg; long secs; @@ -1389,7 +1389,7 @@ pgstat_send_connstats(bool disconnect, TimestampTz last_report) /* session time since the last report */ TimestampDifference(((last_report == 0) ? MyStartTimestamp : last_report), - GetCurrentTimestamp(), + now, &secs, &usecs); msg.m_session_time = secs * 1000000 + usecs; -- 2.26.3