Re: dynamic background workers

On Mon, Jun 24, 2013 at 3:51 AM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
> 3) Why not adding an other function in worker_spi.c being the opposite
> of worker_spi_launch to stop dynamic bgworkers for a given index
> number? This would be only a wrapper of pg_terminate_backend, OK, but
> at least it would give the user all the information needed to start
> and to stop a dynamic bgworker with a single extension, here
> worker_spi.c. It can be painful to stop

Well, there's currently no mechanism for the person who starts a new
backend to know the PID of the process that actually got started. I
plan to write a patch to address that problem, but it's not this
patch.

> 4) Not completely related to this patch, but one sanity check in
> SanityCheckBackgroundWorker:bgworker.c is not listed in the
> documentation: when requesting a database connection, bgworker needs
> to have access to shmem. It looks that this should be also fixed in
> REL9_3_STABLE.

That's fine; I think it's separate from this patch. Please feel free
to propose something.

> 5) Why not adding some documentation? Both dynamic and static
> bgworkers share the same infrastructure, so some lines in the existing
> chapter might be fine?

I'll take a look.

> 6) Just wondering something: it looks that the current code is not
> able to identify what was the way used to start a given bgworker.
> Would it be interesting to be able to identify if a bgworker has been
> registered though RegisterBackgroundWorker or
> RegisterDynamicBackgroundWorker?

I don't think that's a good thing to expose.

--
Robert Haas
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