Re: [HACKERS] walsender & parallelism

On 21 April 2017 at 10:20, Petr Jelinek <petr.jelinek@2ndquadrant.com> wrote:
> On 21/04/17 03:40, Andres Freund wrote:
>>
>> Since [1] walsender (not receiver as commit message says) can execute
>> SQL queries.  While doing some testing of [2] I noticed that SQL queries
>> in walsender get stuck if parallelism is used - I have not investigated
>> why that is yet, but it surely is an issue.  On first blush I'd suspect
>> that some signalling is not wired up correctly (cf. am_walsender branches
>> in PostgresMain() and such).
>
> Looks like SIGUSR1 being different is problem here - it's normally used
> to . I also noticed that we don't handle SIGINT (query cancel).
>
> I'll write proper patch but can you try to just use
> procsignal_sigusr1_handler for SIGUSR1 in walsender.c to see if it fixes
> the issue?

That's what my recovery conflicts for logical decoding on standby
patch does, FWIW.

I haven't found any issues yet..

-- Craig Ringer                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services