| From: | Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
| Cc: | Jelte Fennema-Nio <postgres(at)jeltef(dot)nl>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Denis Laxalde <denis(dot)laxalde(at)dalibo(dot)com>, vignesh C <vignesh21(at)gmail(dot)com>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Greg Stark <stark(at)mit(dot)edu>, "Gregory Stark (as CFM)" <stark(dot)cfm(at)gmail(dot)com>, Jelte Fennema <Jelte(dot)Fennema(at)microsoft(dot)com>, Daniel Gustafsson <daniel(at)yesql(dot)se>, Peter Eisentraut <peter(at)eisentraut(dot)org>, Andres Freund <andres(at)anarazel(dot)de>, Justin Pryzby <pryzby(at)telsasoft(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: [EXTERNAL] Re: Add non-blocking version of PQcancel |
| Date: | 2024-03-13 19:08:30 |
| Message-ID: | CAOYmi+ns77qACkcWFnrxAyJe=KhUfUyt6a9ykbJC_7dv7PAZVw@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Wed, Mar 13, 2024 at 12:01 PM Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> On 2024-Mar-13, Jelte Fennema-Nio wrote:
> > Sadly I'm having a hard time reliably reproducing this race condition
> > locally. So it's hard to be sure what is happening here. Attached is a
> > patch with a wild guess as to what the issue might be (i.e. seeing an
> > outdated "active" state and thus passing the check even though the
> > query is not running yet)
>
> I tried leaving the original running in my laptop to see if I could
> reproduce it, but got no hits ... and we didn't get any other failures
> apart from the three ones already reported ... so it's not terribly high
> probability. Anyway I pushed your patch now since the theory seems
> plausible; let's see if we still get the issue to reproduce. If it
> does, we could make the script more verbose to hunt for further clues.
I hit this on my machine. With the attached diff I can reproduce
constantly (including with the most recent test patch); I think the
cancel must be arriving between the bind/execute steps?
Thanks,
--Jacob
| Attachment | Content-Type | Size |
|---|---|---|
| repro.diff.txt | text/plain | 393 bytes |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Robert Haas | 2024-03-13 19:18:11 | Re: Add system identifier to backup manifest |
| Previous Message | Laurenz Albe | 2024-03-13 19:04:59 | Re: Reports on obsolete Postgres versions |