| From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Sergey Burladyan <eshkinkot(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Looks like merge join planning time is too big, 55 seconds |
| Date: | 2013-08-02 16:23:44 |
| Message-ID: | 20130802162344.GN5669@eldon.alvh.no-ip.org |
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| Lists: | pgsql-performance |
Tom Lane escribió:
> Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:
> > On Thu, Aug 1, 2013 at 5:16 PM, Sergey Burladyan <eshkinkot(at)gmail(dot)com> wrote:
> >> If I not mistaken, may be two code paths like this here:
> >> (1) mergejoinscansel -> scalarineqsel-> ineq_histogram_selectivity -> get_actual_variable_range -> index_getnext
> >> (2) scalargtsel -> scalarineqsel -> ineq_histogram_selectivity -> get_actual_variable_range -> index_getnext
>
> > Yeah, I think you are correct.
>
> mergejoinscansel does *not* call scalarineqsel, nor get_actual_variable_range.
> It calls get_variable_range, which only looks at the pg_statistic entries.
Uh? It's right there in line 2976 in HEAD.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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