Thread: BUG #18156: Self-referential foreign key in partitioned table not enforced on deletes
BUG #18156: Self-referential foreign key in partitioned table not enforced on deletes
From
PG Bug reporting form
Date:
The following bug has been logged on the website: Bug reference: 18156 Logged by: Matthew Gabeler-Lee Email address: fastcat@gmail.com PostgreSQL version: 16.0 Operating system: Linux Description: When a partitioned table has a self-referential foreign key, I'm finding that the key is not enforced during deletes from the table. A simple repro script: create table x ( p int4 not null, i int4 not null, f int4 null, primary key (p, i), foreign key (p, f) references x (p, i) ) partition by list (p); create table x1 partition of x for values in (0); insert into x values (0,1,null), (0,2,1); delete from x where (p,i) = (0,1); select * from x; The final select shows the one row with the clearly violated foreign key values: p | i | f ---+---+--- 0 | 2 | 1 (1 row) I've reproduced this with 15.4 and 16.0 using the official docker images, specifically `postgres/15-alpine` and `postgres/16-alpine`. I haven't tested older versions as my application requires features new to 15.x. I've tried with both list and hash partitioning, and it reproduces with both. I can only reproduce it with self-referential foreign keys and only with partitioned tables. I discovered this with a slightly more complex situation involving an `on delete set null` clause in the FK, but as seen above that is not required to reproduce the issue.
Re: BUG #18156: Self-referential foreign key in partitioned table not enforced on deletes
From
Matthew Gabeler-Lee
Date:
I've since discovered that this is a regression in PG 15.x, with 14.x the delete command correctly fails with an FK violation error.
Is there anything I can do to help investigating a root cause / fix for this issue?
On Fri, Oct 13, 2023 at 10:27 AM PG Bug reporting form <noreply@postgresql.org> wrote:
The following bug has been logged on the website:
Bug reference: 18156
Logged by: Matthew Gabeler-Lee
Email address: fastcat@gmail.com
PostgreSQL version: 16.0
Operating system: Linux
Description:
When a partitioned table has a self-referential foreign key, I'm finding
that the key is not enforced during deletes from the table.
A simple repro script:
create table x (
p int4 not null,
i int4 not null,
f int4 null,
primary key (p, i),
foreign key (p, f) references x (p, i)
)
partition by list (p);
create table x1 partition of x for values in (0);
insert into x values (0,1,null), (0,2,1);
delete from x where (p,i) = (0,1);
select * from x;
The final select shows the one row with the clearly violated foreign key
values:
p | i | f
---+---+---
0 | 2 | 1
(1 row)
I've reproduced this with 15.4 and 16.0 using the official docker images,
specifically `postgres/15-alpine` and `postgres/16-alpine`. I haven't tested
older versions as my application requires features new to 15.x. I've tried
with both list and hash partitioning, and it reproduces with both. I can
only reproduce it with self-referential foreign keys and only with
partitioned tables.
I discovered this with a slightly more complex situation involving an `on
delete set null` clause in the FK, but as seen above that is not required to
reproduce the issue.