Re: Access statistics

Tom Lane wrote:
> Jan Wieck <JanWieck(at)Yahoo(dot)com> writes:
> > So outing myself not beeing a *real programmer*, this is what
> > I have so far:
>
> Hmm ... what is the performance of all this like? Seems like a lot
> of overhead. Can it be turned off?

Current performance loss is about 2-4% wallclock measured. I
expect it to become better when turning some of the functions
into macros.

The plan is to add another column to pg_database that can be
used to turn it on/off on a per database level. Backends just
decide at startup if they collect and send for their session
lifetime.

> > * Backends call some collector functions at various places
> > now (these will finally be macros), that count up table
> > scans, tuples returned by scans, buffer fetches/hits and
> > the like.
>
> Have you removed the existing stats-gathering support
> (backend/access/heap/stats.c and so on)? That would buy back
> at least a few of the cycles involved ...

Not sure if we really should. Let's later decide if it's
really obsolete.

--

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# It's easier to get forgiveness for being wrong than for being right. #
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#================================================== JanWieck(at)Yahoo(dot)com #

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