Re: [PATCH 2/2] repack: repack promisor objects if -a or -A is set

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 8, 2018, 16:17 UTC
Message-ID: <xmqqin4kj0j0.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20180808155045.GB1607@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

> I think that the for_each_packed_object() interface should visit items
> in pack order.

Yeah, that may make more sense. Any order is more logical than the object name order (which by definition is random, so useful only when you want them in a random order), and pack order will give us locality of accesses.

>    For traversals using bitmaps, we have a "name hash cache" in the
>    .bitmap file, which stores the 32-bit hash of the name. That lets us
>    put similar names next to each other without actually knowing the
>    names.

I forgot about that one; it is a neat trick. As .primisor packs are intentionally kept apart from the remainder of the repository, and because .bitmap wants to have a single pack, we cannot just read the .bitmap file for this particular application, though.