Re: Low hanging fruit in lazy-XID-assignment patch?

Simon Riggs wrote:
> On Fri, 2007-09-07 at 06:36 +0200, Florian G. Pflug wrote:
>> Tom Lane wrote:
>>> "Florian G. Pflug" <fgp@phlo.org> writes:
>>> - I actually think with just a little bit of more work, we
>>>> can go even further, and get rid of the ReadNewTransactionId() call
>>>> completely during snapshotting.
>>> [ squint... ]  This goes a bit far for me.  In particular, I think this
>>> will fail in the edge case when there are no live XIDs visible in
>>> ProcArray.  You cannot go back and do ReadNewTransactionId afterward,
>>> at least not without re-scanning the ProcArray a second time, which
>>> makes it at best a questionable win.
>> Why would it?
> 
> I think the additional suggestion goes a bit too far. You may be right,
> but I don't want to change the transaction system in advanced ways this
> close to the next release. We may have difficulty spotting bugs in that
> thinking during beta.

Ok, those were two clear votes against doing this, so I'll stop
arguing ;-). I do think that we should have another look at this when
8.4 opens, though.

greetings, Florian Pflug