Re: [BUG] Fix DETACH with FK pointing to a partitioned table fails

From: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
To: Tender Wang <tndrwang(at)gmail(dot)com>
Cc: Jehan-Guillaume de Rorthais <jgdr(at)dalibo(dot)com>, Junwang Zhao <zhjwpku(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, Alexander Lakhin <exclusion(at)gmail(dot)com>, Guillaume Lelarge <guillaume(at)lelarge(dot)info>, Michael Paquier <michael(at)paquier(dot)xyz>
Subject: Re: [BUG] Fix DETACH with FK pointing to a partitioned table fails
Date: 2024-10-21 21:52:18
Message-ID: 202410212152.ppnqfvqvxu3z@alvherre.pgsql
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On 2024-Oct-21, Tender Wang wrote:

> I suspect that we don't need the below if
> statement anymore.
> /*
> * If the referenced side is partitioned (which we know because our
> * parent's constraint points to a different relation than ours) then
> * we must, in addition to the above, create pg_constraint rows that
> * point to each partition, each with its own action triggers.
> */
> if (parentConForm->conrelid != conform->conrelid)
> {
> ...
> }
>
> The above contidion is always true according to my test.
> I haven't figured out an anti-case.

You're right, this is useless, we can remove the 'if' line. I kept the
block though, to have a place for all those local variable declarations
(otherwise the code looks messier than it needs to).

I also noticed that addFkRecurseReferenced() is uselessly taking a List
**wqueue argument but doesn't use it, so I removed it (as fallout, other
routines don't need it either, especially DetachPartitionFinalize). I
added some commentary on the creation of dependencies in
addFkConstraint().

I also include a few other cosmetic changes; just comment layout
changes.

This time I attach the patch for master only; the others have changed
identically. 14 is unchanged from before. I figured that the conflict
from 14 to 13 was trivial to resolve -- it was just because of DETACH
CONCURRENTLY, so some code moves around, but that's all that happens.

--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/

Attachment Content-Type Size
v5-0001-Restructure-foreign-key-handling-code-for-ATTACH-.patch text/x-diff 47.4 KB

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