Re: [RFC PATCH] index-pack: improve performance on NFS

On Thu, Nov 08, 2018 at 11:20:47PM +0100, Ævar Arnfjörð Bjarmason wrote:

Just a comment on this from the series:

    Note that it is possible for this to actually be _slower_. We'll do a
    full readdir() to fill the cache, so if you have a very large number of
    loose objects and a very small number of lookups, that readdir() may end
    up more expensive.

    In practice, though, having a large number of loose objects is already a
    performance problem, which should be fixed by repacking or pruning via
    git-gc. So on balance, this should be a good tradeoff.

Our biggest repo has a very large number of loose objects at any given
time, but the vast majority of these are because gc *is* happening very
frequently and the default expiry policy of 2wks is in effect.

Having a large number of loose objects is not per-se a performance
problem.

Yes, you're right. I was trying not to get into the rabbit hole of
discussing theoretical tradeoffs, but it is worth addressing. I've
updated that commit message in the patches I'll send out momentarily.

-Peff