[HACKERS] Re: Patch to send transaction commit/rollback stats to the stats collector unconditionally.

[Gurjeet Singh]

On Tue, Jul 1, 2014 at 10:05 AM, Kevin Grittner <kgri...@ymail.com> wrote:
> Tom Lane <t...@sss.pgh.pa.us> wrote:
>
>> If we're going to do it like this, then I think the force flag
>> should be considered to do nothing except override the clock
>> check, which probably means it shouldn't be tested in the initial
>> if() at all.
>
> That makes sense, and is easily done.

Attached is the patch to save you a few key strokes :)

> The only question left is
> how far back to take the patch.  I'm inclined to only apply it to
> master and 9.4.  Does anyone think otherwise?

Considering this as a bug-fix, I'd vote for it to be applied to all
supported releases. But since this may cause unforeseen performance
penalty, I think it should be applied only as far back as the
introduction of PGSTAT_STAT_INTERVAL throttle.

The throttle was implemeted in 641912b, which AFAICT was part of 8.3.
So I guess all the supported releases it is.

Best regards,
-- 
Gurjeet Singh http://gurjeet.singh.im/

EDB : www.EnterpriseDB.com :  The Enterprise PostgreSQL Company

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 3ab1428..c7f41a5 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -753,7 +753,8 @@ pgstat_report_stat(bool force)
 
        /* Don't expend a clock check if nothing to do */
        if ((pgStatTabList == NULL || pgStatTabList->tsa_used == 0) &&
-               !have_function_stats && !force)
+               pgStatXactCommit == 0 && pgStatXactRollback == 0 &&
+               !have_function_stats)
                return;
 
        /*
@@ -817,11 +818,11 @@ pgstat_report_stat(bool force)
        }
 
        /*
-        * Send partial messages.  If force is true, make sure that any pending
-        * xact commit/abort gets counted, even if no table stats to send.
+        * Send partial messages.  Make sure that any pending xact commit/abort
+        * gets counted, even if there are no table stats to send.
         */
        if (regular_msg.m_nentries > 0 ||
-               (force && (pgStatXactCommit > 0 || pgStatXactRollback > 0)))
+               pgStatXactCommit > 0 || pgStatXactRollback > 0)
                pgstat_send_tabstat(&regular_msg);
        if (shared_msg.m_nentries > 0)
                pgstat_send_tabstat(&shared_msg);

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