Re: exposing wait events for non-backends (was: Tracking wait event for latches)

Hi Kuntal,

Patches apply and compile fine.  Works as advertised.

Some minor comments on the patches themselves.

In 0001:

- * pgstat_bestart() -
+ * pgstat_procstart() -
+ *
+ *  Initialize this process's entry in the PgBackendStatus array.
+ *  Called from InitPostgres and AuxiliaryProcessMain.

Not being called from AuxiliaryProcessMain().  Maybe leftover comment from
a previous version.  Actually I see that in patch 0002, Main() functions
of various auxiliary processes call pgstat_procstart, not
AuxiliaryProcessMain.

+     * user-defined functions which expects ids of backends starting from
1 to

s/expects/expect/g

+/*
+ * AuxiliaryPidGetProc -- get PGPROC for an auxiliary process
+ * given its PID
+ *
+ * Returns NULL if not found.
+ */
+PGPROC *
+AuxiliaryPidGetProc(int pid)
+{
+    PGPROC     *result;

Initialize to NULL so that the comment above is true. :)


In 0002:

@@ -248,6 +248,9 @@ BackgroundWriterMain(void)
      */
     prev_hibernate = false;

+    /* report walwriter process in the PgBackendStatus array */
+    pgstat_procstart();
+

s/walwriter/writer/g

Patch 0004 should update monitoring.sgml.

Thanks,
Amit