Re: In-placre persistance change of a relation

At Mon, 2 Sep 2024 09:30:20 +0900, Michael Paquier <michael(at)paquier(dot)xyz> wrote in
> On Sun, Sep 01, 2024 at 10:15:00PM +0300, Heikki Linnakangas wrote:
> > I wonder if the twophase state files and undo log files should be merged
> > into one file. They're similar in many ways: there's one file per
> > transaction, named using the XID. I haven't thought this fully through, just
> > a thought..
>
> Hmm. It could be possible to extract some of this knowledge out of
> twophase.c and design some APIs that could be used for both, but would
> that be really necessary? The 2PC data and the LSNs used by the files
> to check if things are replayed or on disk rely on
> GlobalTransactionData that has its own idea of things and timings at
> recovery.

I'm not sure, but I feel that Heikki mentioned only about using the
file format and in/out functions if the file formats of the two are
sufficiently overlapping.

> Or perhaps your point is actually to do that and add one layer for the
> file handlings and their flush timings? I am not sure, TBH, what this
> thread is trying to fix is complicated enough that it may be better to
> live with two different code paths. But perhaps my gut feeling is
> just wrong reading your paragraph.

I believe this statement is valid, so I’m not in a hurry to do this.

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center