Re: pgsql: Add support for multivariate MCV lists - Mailing list pgsql-committers

From Tomas Vondra
Subject Re: pgsql: Add support for multivariate MCV lists
Date
Msg-id 20190328093046.GF4406@development
Whole thread Raw
In response to Re: pgsql: Add support for multivariate MCV lists  (Andres Freund <andres@anarazel.de>)
List pgsql-committers
On Wed, Mar 27, 2019 at 08:15:35PM -0700, Andres Freund wrote:
>Hi,
>
>On 2019-03-27 21:13:46 +0100, Tomas Vondra wrote:
>> On Wed, Mar 27, 2019 at 12:32:34PM -0700, Peter Geoghegan wrote:
>> > On Wed, Mar 27, 2019 at 12:04 PM Andres Freund <andres@anarazel.de> wrote:
>> > > Congrats, this was long in the making!
>> >
>> > +1
>> >
>>
>> Thanks! I guess it's a Gordie Howe of our patches.
>
>Btw, do you have plans to work on using more of this information during
>join planning? Or at least an estimate of how much work that'd be?
>

Yes, I'd like to use more of this info in join estimation. I don't have
an exact plan how to do that - so if anyone has ideas regarding this,
I'd love to hear them.

An obvious option is to add statistics covering multiple tables (the
syntax is already designed with that in mind). But I have a feeling there
are things we can do without that, e.g. using multivariate MCV lists in
eqjoinsel roughly the same way we use per-column MCV lists, etc.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services 



pgsql-committers by date:

Previous
From: Peter Eisentraut
Date:
Subject: pgsql: doc: Fix typo
Next
From: Masahiko Sawada
Date:
Subject: Re: pgsql: Use FullTransactionId for the transaction stack.