Re: should ConstraintRelationId ins/upd cause relcache invals?

From: Andres Freund <andres(at)anarazel(dot)de>
To: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
Cc: Pg Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
Subject: Re: should ConstraintRelationId ins/upd cause relcache invals?
Date: 2019-01-21 19:33:00
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On 2019-01-21 16:27:50 -0300, Alvaro Herrera wrote:
> While working on bugfixes for FK problems in partitioned tables, I came
> across some behavior that appears to stem from our inclusion of foreign
> keys in relcache, without sufficient care for invalidating the relcache
> entries when the foreign key set for the table changes. (Namely, a
> partition retains its relcache entry with no FKs when an FK is added to
> the parent table, leading a DELETE to skip running action triggers).
> At I posted
> a simplistic for the specific problem I found by calling
> CacheInvalidateRelcache in the problem spot. But I'm wondering if the
> correct fix isn't to have CacheInvalidateHeapTuple deal with FK
> pg_constraint tuples instead, per the attached patch. Why does this not
> lead to stale cache problems elsewhere?
> FKs were added to relcache entries by commit 100340e2dcd0 ("Restore
> foreign-key-aware estimation of join relation sizes"), so CCing Tom and
> Tomas.

I wondered about the same in
, just about pg_index, but people didn't like it much.


Andres Freund

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