From: Junio C Hamano <gitster@pobox•com>
To: "Nguyễn Thái Ngọc Duy" <pclouds@gmail•com>
Cc: git@vger•kernel.org, msporleder@gmail•com
Subject: Re: [PATCH v2 2/2] index-pack: kill union delta_base to save memory
Date: Fri, 27 Feb 2015 13:18:58 -0800 [thread overview]
Message-ID: <xmqqzj7zhx31.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <1424947928-19396-3-git-send-email-pclouds@gmail.com> ("Nguyễn Thái Ngọc Duy"'s message of "Thu, 26 Feb 2015 17:52:08 +0700")
Nguyễn Thái Ngọc Duy <pclouds@gmail•com> writes:
> Notice that with "recent" Git versions, ofs-delta objects are
> preferred over ref-delta objects and ref-delta objects have no reason
> to be present in a clone pack.
It is true that we try to use ofs-delta as much as possible, but
where does "have no reason to be present" come from?
When an object cannot be represented as an ofs-delta (which can only
refer backwards), don't we use ref-delta, instead of storing it as a
deflated-full object?
Probably "Not so ancient versions of Git tries to use ofs-delta
encoding whenever possible, so it is expected that objects encoded
using ref-delta are minority" may be closer to the truth. And that
observation does justify why using two separate pools (one with
8-byte entries for ofs-delta, the other with 20-byte entries for
ref-delta) is a better idean than using one pool with 20-byte
entries for both kinds.
next prev parent reply other threads:[~2015-02-27 21:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-20 1:58 [PATCH 0/2] nd/slim-index-pack-memory-usage updates Nguyễn Thái Ngọc Duy
2015-02-20 1:58 ` [PATCH 1/2] index-pack: reduce object_entry size to save memory Nguyễn Thái Ngọc Duy
2015-02-23 2:37 ` Junio C Hamano
2015-02-23 3:38 ` Duy Nguyen
2015-02-20 1:58 ` [PATCH 2/2] index-pack: kill union delta_base " Nguyễn Thái Ngọc Duy
2015-02-26 10:52 ` [PATCH v2 0/2] nd/slim-index-pack-memory-usage updates Nguyễn Thái Ngọc Duy
2015-02-26 10:52 ` [PATCH v2 1/2] index-pack: reduce object_entry size to save memory Nguyễn Thái Ngọc Duy
2015-02-26 10:52 ` [PATCH v2 2/2] index-pack: kill union delta_base " Nguyễn Thái Ngọc Duy
2015-02-27 21:18 ` Junio C Hamano [this message]
2015-02-28 11:44 ` Duy Nguyen
2015-03-01 2:37 ` Junio C Hamano
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