RE: [PoC] Non-volatile WAL buffer

Dear Amit,

Thank you for your advice. Exactly, it's so to speak "do as the hackers do when in pgsql"...

I'm rebasing my branch onto master. I'll submit an updated patchset and performance report later.

Best regards,
Takashi

--
Takashi Menjo <takashi(dot)menjou(dot)vg(at)hco(dot)ntt(dot)co(dot)jp>
NTT Software Innovation Center

> -----Original Message-----
> From: Amit Langote <amitlangote09(at)gmail(dot)com>
> Sent: Monday, February 17, 2020 5:21 PM
> To: Takashi Menjo <takashi(dot)menjou(dot)vg(at)hco(dot)ntt(dot)co(dot)jp>
> Cc: Robert Haas <robertmhaas(at)gmail(dot)com>; Heikki Linnakangas <hlinnaka(at)iki(dot)fi>; PostgreSQL-development
> <pgsql-hackers(at)postgresql(dot)org>
> Subject: Re: [PoC] Non-volatile WAL buffer
>
> Hello,
>
> On Mon, Feb 17, 2020 at 4:16 PM Takashi Menjo <takashi(dot)menjou(dot)vg(at)hco(dot)ntt(dot)co(dot)jp> wrote:
> > Hello Amit,
> >
> > > I apologize for not having any opinion on the patches themselves,
> > > but let me point out that it's better to base these patches on HEAD
> > > (master branch) than REL_12_0, because all new code is committed to
> > > the master branch, whereas stable branches such as REL_12_0 only receive bug fixes. Do you have any
> specific reason to be working on REL_12_0?
> >
> > Yes, because I think it's human-friendly to reproduce and discuss performance measurement. Of course I know
> all new accepted patches are merged into master's HEAD, not stable branches and not even release tags, so I'm
> aware of rebasing my patchset onto master sooner or later. However, if someone, including me, says that s/he
> applies my patchset to "master" and measures its performance, we have to pay attention to which commit the
> "master" really points to. Although we have sha1 hashes to specify which commit, we should check whether the
> specific commit on master has patches affecting performance or not because master's HEAD gets new patches day
> by day. On the other hand, a release tag clearly points the commit all we probably know. Also we can check more
> easily the features and improvements by using release notes and user manuals.
>
> Thanks for clarifying. I see where you're coming from.
>
> While I do sometimes see people reporting numbers with the latest stable release' branch, that's normally just one
> of the baselines.
> The more important baseline for ongoing development is the master branch's HEAD, which is also what people
> volunteering to test your patches would use. Anyone who reports would have to give at least two numbers --
> performance with a branch's HEAD without patch applied and that with patch applied -- which can be enough in
> most cases to see the difference the patch makes. Sure, the numbers might change on each report, but that's fine
> I'd think. If you continue to develop against the stable branch, you might miss to notice impact from any relevant
> developments in the master branch, even developments which possibly require rethinking the architecture of your
> own changes, although maybe that rarely occurs.
>
> Thanks,
> Amit