Re: [CORE] FOR SHARE vs FOR UPDATE locks - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [CORE] FOR SHARE vs FOR UPDATE locks
Date
Msg-id 1582.1165001233@sss.pgh.pa.us
Whole thread Raw
In response to Re: [CORE] FOR SHARE vs FOR UPDATE locks  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
Bruce Momjian <bruce@momjian.us> writes:
> Josh Berkus wrote:
>> So, I think it needs to go on the list for 8.2.1 or 8.3 (depending on what 
>> changes the fix requires) but I don't think we should hold up the release.

> We cannot add something this major in a minor release --- it would have
> to be 8.3.

If someone thinks of a brilliant solution that doesn't change on-disk
layout, maybe we could implement it in 8.2.x, but right now I'm not
feeling hopeful about that.

The best idea I have at the moment is that we might be able to do
something as part of the proposed plan to fold cmin/cmax into a single
field.  The thought there was that there could be some in-memory state
for tuples that had been modified multiple times by a single xact ---
perhaps that could be extended to cover this problem.  This is just
handwaving at the moment though.  In particular, is-the-tuple-locked-or-not
seems like it has to be externally visible state, so maybe it can't work.
        regards, tom lane


pgsql-hackers by date:

Previous
From: Bruce Momjian
Date:
Subject: Re: [CORE] FOR SHARE vs FOR UPDATE locks
Next
From: "Merlin Moncure"
Date:
Subject: Re: FOR SHARE vs FOR UPDATE locks