Re: [HACKERS] Removing [Merge]Append nodes which contain a single subpath - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [HACKERS] Removing [Merge]Append nodes which contain a single subpath
Date
Msg-id 9810.1509048365@sss.pgh.pa.us
Whole thread Raw
In response to Re: [HACKERS] Removing [Merge]Append nodes which contain a single subpath  (David Rowley <david.rowley@2ndquadrant.com>)
Responses Re: [HACKERS] Removing [Merge]Append nodes which contain a single subpath
List pgsql-hackers
David Rowley <david.rowley@2ndquadrant.com> writes:
> On 27 October 2017 at 01:44, Ashutosh Bapat
> <ashutosh.bapat@enterprisedb.com> wrote:
>> I think Antonin has a point. The join processing may deem some base
>> relations dummy (See populate_joinrel_with_paths()). So an Append
>> relation which had multiple child alive at the end of
>> set_append_rel_size() might ultimately have only one child after
>> partition-wise join has worked on it.

TBH, that means partition-wise join planning is broken and needs to be
redesigned.  It's impossible that we're going to make sane planning
choices if the sizes of relations change after we've already done some
planning work.
        regards, tom lane


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

pgsql-hackers by date:

Previous
From: Peter Eisentraut
Date:
Subject: Re: [HACKERS] [GENERAL] Postgres 10 manual breaks links with anchors
Next
From: Tom Lane
Date:
Subject: Re: [HACKERS] [GENERAL] Postgres 10 manual breaks links with anchors