Re: Looks like merge join planning time is too big, 55 seconds - Mailing list pgsql-performance

Jeff Janes <jeff.janes@gmail.com> writes:
> On Thu, Aug 1, 2013 at 5:16 PM, Sergey Burladyan <eshkinkot@gmail.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.

I think we need to see the actual stack traces, not incomplete versions.
It's possible that the situation here involves bloat in pg_statistic, but
we're just leaping to conclusions if we assume that that's where the index
fetches are occurring.

            regards, tom lane