Re: [PATCH 1/7] bulk-checkin: rename 'state' variable and separate 'plugged' boolean

[Neeraj Singh <nksingh85@gmail.com>]

On Wed, Mar 16, 2022 at 9:14 AM Junio C Hamano <gitster@pobox.com> wrote:
>
> Neeraj Singh <nksingh85@gmail.com> writes:
>
> > I think my new usage is congruent with the existing API, which seems
> > to be about combining multiple add operations into a large transaction,
> > where we can do some cleanup operations once we're finished. In the
> > preexisting code, the transaction is about adding a bunch of large objects
> > to a single pack file (while leaving small objects loose), and then completing
> > the packfile when the adds are finished.
>
> OK, so it was part me, and part a suboptimal presentation, I guess
> ;-)
>
> Let me rephrase the idea to see if I got it right this time.
>
> The bulk-checkin API has two interesting entry points, "plug" that
> signals that we are about to repeat possibly many operations to add
> new objects to the object store, and "unplug" that signals that we
> are done such adding.  They are meant to serve as a hint for the
> object layer to optimize its operation.
>
> So far the only way the hint was used was that the logic that sends
> an overly large object into a packfile (instead of storing it loose,
> which leaves it subject to expensive repacking later) can shove more
> than one such objects in the same packfile.
>
> This series invents another use of the "plug"-"unplug" hint.  By
> knowing that many loose object files are created and when the series
> of object creation ended, we can avoid having to fsync each and
> every one of them on certain filesystems and achieve the same
> robustness.  The new "batch" option to core.fsyncmethod triggers
> this mechanism.
>
> Did I get it right, more-or-less?

Yes, that's my understanding as well.

Thanks,
Neeraj