Re: [PATCH v2] read_index_from(): Skip verification of the cache entry order to speed index loading

From: Jeff King <peff@peff.net>
Date: Oct 30, 2017, 18:03 UTC
Message-ID: <20171030180334.ddursnmj5wqgimqu@sigill.intra.peff.net>
In-Reply-To: <11666ccf-6406-d585-f519-7a1934c2973a@gmail.com>

On Mon, Oct 30, 2017 at 08:48:48AM -0400, Ben Peart wrote:

> Any updates or thoughts on this one?  While the patch has become quite
> trivial, it does results in a savings of 5%-15% in index load time.

I like the general direction of avoiding the check during each read. But...

Show 5 quoted lines

> I thought the compromise of having this test only run when DEBUG is defined
> should limit it to developer builds (hopefully everyone developing on git is
> running DEBUG builds :)).  Since the test is trying to detect buggy code
> when writing the index, I thought that was the right time to test/catch any
> issues.

I certainly don't build with DEBUG. It traditionally hasn't done anything useful. But I'm also not convinced that this is a likely way to find bugs in the first place, so I'm OK missing out on it.

But what we probably _do_ need is to make sure that "git fsck" would detect such an out-of-order index. So that developers and users alike can diagnose suspected problems.

-Peff