Re: How does this FK constraint error happen?

On 7/15/24 08:18, Ron Johnson wrote:
> On Mon, Jul 15, 2024 at 11:06 AM Adrian Klaver
> <adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>> wrote:
>
> On 7/15/24 07:53, Ron Johnson wrote:
> > On Mon, Jul 15, 2024 at 10:35 AM Peter J. Holzer

> > TAPd=# select * from rel_group_user
> > where user_id between 1100 and 1300
> > order by user_id;
> >   user_id | group_id | modified_by |       modified_on
> > ---------+----------+-------------+-------------------------
> >      1133 |        2 |        1133 | 2024-07-15 08:43:35.669
> >      1142 |        2 |        1142 | 2024-07-15 09:05:58.451
> >      1147 |        2 |        1147 | 2024-07-15 09:30:37.169
> >      1158 |        2 |        1158 | 2024-07-15 09:36:45.142
> >      1197 |        2 |        1197 | 2024-07-15 09:52:58.477
> >      1210 |        2 |        1210 | 2024-07-15 02:42:09.355
> <<<<<<<<<<<<<
>
> Time travel?
>
>
> 😞
>
>
> 2024-07-15 02:41:15 Deleting from
> FISPTAPPGS401DA/TAPd.public.access_user
> DELETE FROM public.access_user;
>
> Or do the cron jobs take that long to execute?
>
>
> The deletes from 26*3 tables (the same 26 tables in three children) took
> from 02:40:02 to 02:41:47.
> Then a bunch of COPY statements run (pg_dump from the federation master,
> then COPY to the federation children).  Must be done in a specific order.

I don't think it is entirely coincidental that 1210 is the only shown
user_id with a modified_on value that is in proximity to the delete
error. My suspicion is that actions are not happening in the exact order
you think they are. I would think that combining DELETE FROM
rel_group_user; and DELETE FROM public.access_user; in a single
transaction would be a good start to fixing this.

>
> How is modified_on created?
>
>
> It's updated by the application.

At what point in the process?

>
> >      1229 |        2 |        1229 | 2024-07-15 08:33:48.443
> >      1242 |        2 |        1242 | 2024-07-15 10:29:51.176
> >      1260 |        2 |        1260 | 2024-07-15 07:36:21.182
> >      1283 |        2 |        1283 | 2024-07-15 09:48:25.214
> >      1288 |        2 |        1288 | 2024-07-15 08:10:33.609
> > (11 rows)
> >
> > TAPd=# select user_id, login_id, created_on, modified_on
> > TAPd-# from public.access_user
> > TAPd-# where user_id = 1210;
> >   user_id |  login_id  |       created_on        |       modified_on
> >
> ---------+------------+-------------------------+-------------------------
> >      1210 | JORIEUSER3 | 2023-10-20 11:54:24.562 | 2024-07-15
> 02:42:09.355
> > (1 row)
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com