Re: Threading in BGWorkers (!) - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Threading in BGWorkers (!)
Date
Msg-id 2124260.1592883496@sss.pgh.pa.us
Whole thread Raw
In response to Threading in BGWorkers (!)  (James Sewell <james.sewell@jirotech.com>)
Responses Re: Threading in BGWorkers (!)  (Eric Ridge <eebbrr@gmail.com>)
Re: Threading in BGWorkers (!)  (James Sewell <james.sewell@jirotech.com>)
Re: Threading in BGWorkers (!)  (Konstantin Knizhnik <k.knizhnik@postgrespro.ru>)
Re: Threading in BGWorkers (!)  (Chapman Flack <chap@anastigmatix.net>)
List pgsql-hackers
James Sewell <james.sewell@jirotech.com> writes:
> I was talking about PostgreSQL and threading on IRC the other day - which I
> know is a frowned upon topic - and just wanted to frame the same questions
> here and hopefully get a discussion going.

I think the short answer about threading in bgworkers (or any other
backend process) is "we don't support it; if you try it and it breaks,
which it likely will, you get to keep both pieces".  I'm not sure that
there's any merit in making small dents in that policy.  I suspect that
at some point, somebody will try to move those goalposts a long way,
but it will be a large and controversial patch.

Why do you want threads in a bgworker anyway?  You could spawn multiple
bgworkers, or you could dispatch the threaded work to a non-Postgres-ish
process as PL/Java does.  The only advantage I can see of doing work in a
process that's not at arm's-length is to have access to PG computational
or IPC facilities, and none of that is likely to work safely in a threaded
context.

            regards, tom lane



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