Re: Patch to send transaction commit/rollback stats to the stats collector unconditionally. - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Patch to send transaction commit/rollback stats to the stats collector unconditionally.
Date
Msg-id 12754.1395271672@sss.pgh.pa.us
Whole thread Raw
In response to Re: Patch to send transaction commit/rollback stats to the stats collector unconditionally.  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Responses Re: Patch to send transaction commit/rollback stats to the stats collector unconditionally.  (Robert Haas <robertmhaas@gmail.com>)
Re: Patch to send transaction commit/rollback stats to the stats collector unconditionally.  (Gurjeet Singh <gurjeet@singh.im>)
List pgsql-hackers
Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> I'm not sure I understand the point of this whole thing.  Realistically,
> how many transactions are there that do not access any database tables?

I think that something like "select * from pg_stat_activity" might not
bump any table-access counters, once the relevant syscache entries had
gotten loaded.  You could imagine that a monitoring app would do a long
series of those and nothing else (whether any actually do or not is a
different question).

But still, it's a bit hard to credit that this patch is solving any real
problem.  Where's the user complaints about the existing behavior?
That is, even granting that anybody has a workload that acts like this,
why would they care ... and are they prepared to take a performance hit
to avoid the counter jump after the monitoring app exits?
        regards, tom lane



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