Re: foreign key locks, 2nd attempt

Excerpts from Simon Riggs's message of jue mar 15 18:46:44 -0300 2012:
> 
> On Thu, Mar 15, 2012 at 1:17 AM, Alvaro Herrera
> <alvherre@commandprompt.com> wrote:
> 
> > As things stand today
> 
> Can I confirm where we are now? Is there another version of the patch
> coming out soon?

Here is v11.  This version is mainly updated to add pg_upgrade support,
as discussed.  It also contains the README file that was posted earlier
(plus wording fixes per Bruce), a couple of bug fixes, and some comment
updates.

There's also a SRF for inspecting multixact members, pg_get_multixact_members, 
but I'm not sure how useful it is for the general user so maybe I'll rip
it out of the patch before committing.

I mentioned elsewhere in the thread that ResetMultiHintBit was bogus: we
don't know, while running the various HeapTupleSatisfies routines, what
kind of lock we hold; so we can't do anything to the tuple beyond
setting HEAP_XMAX_INVALID.  There's probably a good place in page
pruning that could be used to transform multis containing committed
updates into plain no-multi Xmax.

The whole thing can be seen in github here:
https://github.com/alvherre/postgres/tree/fklocks

(While creating this patch I noticed that I had created v10 of the patch
on March 6th but apparently never sent it.)

-- 
Álvaro Herrera <alvherre@commandprompt.com>
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