| From: | Jaime Casanova <jaime(at)2ndquadrant(dot)com> |
|---|---|
| To: | Mark Kirkwood <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz> |
| Cc: | Satoshi Nagayasu <snaga(at)uptime(dot)jp>, Peter Eisentraut <peter_e(at)gmx(dot)net>, Greg Smith <greg(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [PoC] pgstattuple2: block sampling to reduce physical read |
| Date: | 2013-10-11 04:33:12 |
| Message-ID: | CAJKUy5g1Kh8Urc1nSUDOyTG_b3opBVjp=7_ZBjgiGdPutee-jQ@mail.gmail.com |
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On Thu, Oct 10, 2013 at 5:32 PM, Mark Kirkwood
<mark(dot)kirkwood(at)catalyst(dot)net(dot)nz> wrote:
>
> Quietly replying to myself - looking at the code the sampler does 3000
> random page reads...
FWIW, something that bothers me is that there is 3000 random page
reads... i mean, why 3000? how do you get that number as absolute for
good accuracy in every relation? why not a percentage, maybe an
argument to the function?
also the name pgstattuple2, doesn't convince me... maybe you can use
pgstattuple() if you use a second argument (percentage of the sample)
to overload the function
--
Jaime Casanova www.2ndQuadrant.com
Professional PostgreSQL: Soporte 24x7 y capacitación
Phone: +593 4 5107566 Cell: +593 987171157
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