Re: dynamic background workers

On Mon, Jun 17, 2013 at 10:45 PM, Peter Eisentraut <peter_e@gmx.net> wrote:
> On Fri, 2013-06-14 at 17:00 -0400, Robert Haas wrote:
>> Alvaro's work on 9.3, we now have the ability to configure background
>> workers via shared_preload_libraries.  But if you don't have the right
>> library loaded at startup time, and subsequently wish to add a
>> background worker while the server is running, you are out of luck.
>
> We could tweak shared_preload_libraries so that it reacts sensibly to
> reloads.  I basically gave up on that by writing
> session_preload_libraries, but if there is more general use for that, we
> could try.
>
> (That doesn't invalidate your work, but it's a thought.)

Yeah, I thought about that.  But it doesn't seem possible to do
anything all that sane.  You can't unload libraries if they've been
removed; you can potentially load new ones if they've been added.  But
that's a bit confusing, if the config file says that's what's loaded
is bar, and what's actually loaded is foo, bar, baz, bletch, and quux.

Some variant of this might still be worth doing, but figuring out the
details sounded like more than I wanted to get into, so I punted.  :-)

-- 
Robert Haas
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