Re: Funny hang on PostgreSQL 10 during parallel index scan on slave

Yep, Maybe we should check for signals there.

On Wed, Sep 5, 2018 at 5:27 PM Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
wrote:

> On Wed, Sep 5, 2018 at 8:23 AM Chris Travers <chris(dot)travers(at)adjust(dot)com>
> wrote:
> > 1. The query is in a parallel index scan or similar
> > 2. A process is executing a parallel plan and allocating a significant
> chunk of memory (2MB for example) in dynamic shared memory.
> > 3. The startup process goes into a loop where it sends a sigusr1,
> sleeps 5m, and sends another sigusr1 etc.
> > 4. The sigusr1 aborts the system call, which is then retried.
> > 5. Because the system call takes more than 5ms, we end up in an endless
> loop
>
> Do you mean this loop in dsm_impl_posix_resize() is getting
> interrupted constantly and never completing?
>
> /* We may get interrupted, if so just retry. */
> do
> {
> rc = posix_fallocate(fd, 0, size);
> } while (rc == EINTR);
>
> --
> Thomas Munro
> http://www.enterprisedb.com
>

--
Best Regards,
Chris Travers
Head of Database

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