| From: | Petr Jelinek <petr(dot)jelinek(at)2ndquadrant(dot)com> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de>, pgsql-hackers(at)postgresql(dot)org, Petr Jelinek <petr(at)2ndquadrant(dot)com>, Peter Eisentraut <peter_e(at)gmx(dot)net> |
| Subject: | Re: walsender & parallelism |
| Date: | 2017-04-21 02:20:26 |
| Message-ID: | e41081d2-080f-b612-2084-549fa652fae2@2ndquadrant.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
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?
BTW while looking at the code, I don't understand why we call
latch_sigusr1_handler after calling SetLatch(MyLatch), shouldn't just
the SetLatch be enough (they both end up calling sendSelfPipeByte()
eventually)?
--
Petr Jelinek http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Noah Misch | 2017-04-21 02:24:12 | Re: tablesync patch broke the assumption that logical rep depends on? |
| Previous Message | Stephen Frost | 2017-04-21 01:53:28 | Re: pg_dump emits ALTER TABLE ONLY partitioned_table |