updated qCache

Hi all,

Here's an updated version of the experimental qCache patch I
posted a couple days ago (which is a port of Karel Zak's 7.0
work to CVS HEAD).

Changes:

- fix segfault in EXECUTE under some circumstances (reported
  by Barry Lind)
- fix some memory leaks  (thanks to Karel Zak)
- write more regression tests (make check still won't pass)
- re-diff against CVS HEAD
- more code cleanup, minor tweaks

However, I've tentatively decided that I think the best
way to go forward is to rewrite this code. IMHO the utility of
plans cached in shared memory is fairly limited, but the
code that implements this adds a lot of complex to the patch.
I'm planning to re-implement PREPARE/EXECUTE with support only
for locally-prepared plans, using the existing patch as a
guide. The result should be a simpler patch -- once it's
in CVS we can worry about more advanced plan caching
techiques. Any complaints/comments on this plan?

Cheers,

Neil

--
Neil Conway <neilconway@rogers.com>
PGP Key ID: DB3C29FC