Re: No hash join across partitioned tables? - Mailing list pgsql-performance

From Tom Lane
Subject Re: No hash join across partitioned tables?
Date
Msg-id 29559.1287206562@sss.pgh.pa.us
Whole thread Raw
In response to Re: No hash join across partitioned tables?  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: No hash join across partitioned tables?  (Samuel Gendler <sgendler@ideasculptor.com>)
Re: No hash join across partitioned tables?  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-performance
Alvaro Herrera <alvherre@commandprompt.com> writes:
> If we analyze the parent, do we also update the children stats, or is it
> just that we keep two stats for the parent, one with children and one
> without, both being updated when the parent is analyzed?

The latter.

The trick here is that we need to fire an analyze on the parent even
though only its children may have had any updates.

> If the latter's the case, maybe we should modify ANALYZE a bit more, so
> that we can analyze the whole hierarchy in one go, and store the lot of
> stats with a single pass (each child alone, the parent alone, the parent
> plus children).  However it's not real clear how would this work with
> multiple inheritance levels.

It's also not clear how it works without blowing out memory...

            regards, tom lane

pgsql-performance by date:

Previous
From: Alvaro Herrera
Date:
Subject: Re: No hash join across partitioned tables?
Next
From: Samuel Gendler
Date:
Subject: Re: No hash join across partitioned tables?