Re: Optimize join selectivity estimation by not reading MCV stats for unique join attributes - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Optimize join selectivity estimation by not reading MCV stats for unique join attributes
Date
Msg-id 2185327.1668782744@sss.pgh.pa.us
Whole thread Raw
In response to Re: Optimize join selectivity estimation by not reading MCV stats for unique join attributes  (Tomas Vondra <tomas.vondra@enterprisedb.com>)
List pgsql-hackers
Tomas Vondra <tomas.vondra@enterprisedb.com> writes:
> On 11/18/22 09:54, David Geier wrote:
>> I couldn't come up with any reasonable way of writing an automated test
>> for that.

> I don't think you can write a test for this, because there is no change
> to behavior that can be observed by the user.

Yeah, and the delta in performance is surely too small to be
measured reliably in the buildfarm.  I think coverage will have
to be sufficient.

            regards, tom lane



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