Обсуждение: Rename latestCompletedXid to latestCommittedXid

Hi

Per my post to the hackers list, here is a patch that renamed
latestCompletedXid to latestCommittedXid, and updates it only
on commits.

greetings, Florian Pflug

"Florian G. Pflug" <fgp@phlo.org> writes:
> Per my post to the hackers list, here is a patch that renamed
> latestCompletedXid to latestCommittedXid, and updates it only
> on commits.

This is wrong --- it will break early detection of aborted
subtransactions.

            regards, tom lane

Tom Lane wrote:
> "Florian G. Pflug" <fgp@phlo.org> writes:
>> Per my post to the hackers list, here is a patch that renamed
>> latestCompletedXid to latestCommittedXid, and updates it only
>> on commits.
>
> This is wrong --- it will break early detection of aborted
> subtransactions.

I don't see how - TransactionIdIsInProgress doesn't even touch
latestCompletedXid. And I didn't mess with XidCacheRemoveRunningXids,
other than removing the latestCompletedXid updating.

Am I missing something?

greetings, Florian Pflug

"Florian G. Pflug" <fgp@phlo.org> writes:
> Tom Lane wrote:
>> This is wrong --- it will break early detection of aborted
>> subtransactions.

> I don't see how - TransactionIdIsInProgress doesn't even touch
> latestCompletedXid.

Nah, I take that back --- I was worried that XidInMVCCSnapshot might
say it was still running when it wasn't, but we never apply
XidInMVCCSnapshot to XIDs that we haven't already determined to be
committed, so it doesn't matter.

It's still a bad idea though.  Let me go respond to your -hackers
post (which arrived here after the other one).

            regards, tom lane