Re: Threading in BGWorkers (!)

James Sewell <james(dot)sewell(at)jirotech(dot)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