Re: DISCARD ALL ; stored procedures

On Fri, Jan 7, 2011 at 1:29 PM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
> #1. Add a new 'Top-but-removed-on-DISCARD' context and modify the PLs to
>    use that instead of TopMemoryContext and require any other contexts
>        they create to be children of it.

I'm guessing that just resetting the memory context is going to result
in things breaking all over the place - the PL might have dangling
pointers into the context. And it might have other resources that we
don't know about. Thus I think we need:

> #2. Add another entry point to the PLs in pg_pltemplate.h which is a
>    function to be called on DISCARD.

...except I think that the principal thing you need to modify is
pl_language, rather than pl_pltemplate.

If we go this route, then (1) it can't be back-patched, obviously, and
(2) we need to think a little bit harder about what we're asking to
have discarded, because I think it's going to be a lot more than just
cached plans.

--
Robert Haas
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