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From: Shawn Pearce <spearce@spearce.org>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: git <git@vger.kernel.org>, Jeff King <peff@peff.net>,
	Junio C Hamano <gitster@pobox.com>,
	David Borowitz <dborowitz@google.com>
Subject: Re: reftable [v3]: new ref storage format
Date: Fri, 28 Jul 2017 19:31:31 -0700	[thread overview]
Message-ID: <CAJo=hJt5A6wL1i4d8WAivL-+LymZd_M6XjUBJ+vVoYfvuVm23w@mail.gmail.com> (raw)
In-Reply-To: <CAMy9T_F9oH926ShUGpFqJz4bMrJofvbsfb0_oME2NhsYvObq9Q@mail.gmail.com>

On Fri, Jul 28, 2017 at 7:18 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:
> On Fri, Jul 28, 2017 at 3:12 PM, Shawn Pearce <spearce@spearce.org> wrote:
>> I'm with you this far, and like the {min,max}_update_index in the
>> header. I'm concerned about update_index in 32 bits. At some point you
>> need to reset the counter, or the repository is broken. 4b updates is
>> enough for anyone? I'd feel better about this being a 64 bit field.
>
> Yes, I was a little bit nervous about 32 bits, too. But that's a *lot*
> of updates: one per second for 136 years. If that limit were ever
> reached, there could be a compaction step, where any update indices
> that don't have associated reflog entries are "compacted out" of the
> numerical sequence and the remaining indices are renumbered
> contiguously.

I considered that, but its a bit of a pain for the writer to renumber
the remaining records.

> But it's ok with me to make it 64 bits. Usually those extra bytes
> would be appear as FFFFFFFF and so should prefix- and zlib-compress
> well.

That was my thought. Within a single reference these will prefix
compress right out, and zlib will fix any sins within the log block at
restart points.

      reply	other threads:[~2017-07-29  2:31 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-22 18:29 reftable [v3]: new ref storage format Shawn Pearce
2017-07-23 20:32 ` Ævar Arnfjörð Bjarmason
2017-07-24 22:22 ` Stefan Beller
2017-07-24 23:00   ` Shawn Pearce
2017-07-27 10:04     ` Stefan Beller
2017-07-27 14:28 ` Michael Haggerty
2017-07-28 22:12   ` Shawn Pearce
2017-07-29  2:18     ` Michael Haggerty
2017-07-29  2:31       ` Shawn Pearce [this message]

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