Re: Hash join explain is broken
Andres Freund <andres@anarazel.de>
From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alexander Korotkov <a.korotkov@postgrespro.ru>,pgsql-hackers
<pgsql-hackers@postgresql.org>
Date: 2019-06-13T23:23:34Z
Lists: pgsql-hackers
Hi, On June 13, 2019 3:38:47 PM PDT, Tom Lane <tgl@sss.pgh.pa.us> wrote: >Andres Freund <andres@anarazel.de> writes: >> I am too tired to look further into this. I suspect the only reason >we >> didn't previously run into trouble with the executor stashing >hashkeys >> manually at a different tree level with: >> ((HashState *) innerPlanState(hjstate))->hashkeys >> is that hashkeys itself isn't printed... > >TBH, I think 5f32b29c is just wrong and should be reverted for now. >If there's a need to handle those expressions differently, it will >require some cooperation from the planner not merely a two-line hack >in executor startup. That commit didn't include any test case or >other demonstration that it was solving a live problem, so I think >we can leave it for v13 to address the issue. I'm pretty sure you'd get an assertion failure if you reverted it (that's why it was added). So it's a bit more complicated than that. Unfortunately I'll not get back to work until Monday, but I'll spend time on this then. Andres -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
Commits
-
Fix representation of hash keys in Hash/HashJoin nodes.
- a668bc75996d 12.0 landed
- 2abd7ae9b20b 13.0 landed