Flush any remaining statistics counts out to the collector at process

exit.  Without this, operations triggered during backend exit (such as
temp table deletions) won't be counted ... which given heavy usage of
temp tables can lead to pg_autovacuum falling way behind on the need
to vacuum pg_class and pg_attribute.  Per reports from Steve Crawford
and others.

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index c32ebbaac34e3a4532a91c51aa978075138a95a9..dad632098afa2aa89993469e31636970c959e464 100644 (file)
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -109,6 +109,7 @@ static char pgStat_fname[MAXPGPATH];
 static void pgstat_main(void);
 static void pgstat_recvbuffer(void);
 static void pgstat_die(SIGNAL_ARGS);
+static void pgstat_beshutdown_hook(int code, Datum arg);
 
 static int     pgstat_add_backend(PgStat_MsgHdr *msg);
 static void pgstat_sub_backend(int procpid);
@@ -522,6 +523,25 @@ pgstat_bestart(void)
 
        pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_BESTART);
        pgstat_send(&msg, sizeof(msg));
+
+       /*
+        * Set up a process-exit hook to ensure we flush the last batch of
+        * statistics to the collector.
+        */
+       on_proc_exit(pgstat_beshutdown_hook, 0);
+}
+
+/*
+ * Flush any remaining statistics counts out to the collector at process
+ * exit.   Without this, operations triggered during backend exit (such as
+ * temp table deletions) won't be counted.  This is an on_proc_exit hook,
+ * not on_shmem_exit, so that everything interesting must have happened
+ * already.
+ */
+static void
+pgstat_beshutdown_hook(int code, Datum arg)
+{
+       pgstat_report_tabstat();
 }