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Re: Index files autocompletion too slow in big repositories (w / suggestion for improvement)




Cc Gábor, resent with working email (hopefully); please follow-up on this mail.

Am 15.04.2017 um 00:33 schrieb Ævar Arnfjörð Bjarmason:
On Sat, Apr 15, 2017 at 12:08 AM, Carlos Pita <carlosjosepita@xxxxxxxxx> wrote:
This is much faster (below 0.1s):

__git_index_files ()
{
    local dir="$(__gitdir)" root="${2-.}" file;
    if [ -d "$dir" ]; then
        __git_ls_files_helper "$root" "$1" | \
            sed -r 's@/.*@@' | uniq | sort | uniq
    fi
}

time __git_index_files

real    0m0.075s
user    0m0.083s
sys    0m0.010s

Most of the improvement is due to the simpler, non-grouping, regex.
Since I expect most of the common prefixes to arrive consecutively,
running uniq before sort also improves things a bit. I'm not removing
leading double quotes anymore (this isn't being done by the current
version, anyway) but this doesn't seem to hurt.

Despite the dependence on sed this is ten times faster than the
original, maybe an option to enable fast index completion or something
like that might be desirable.

It's fine to depend on sed, these shell-scripts are POSIX compatible,
and so is sed, we use sed in a lot of the built-in shellscripts.

This is about command line completion. We go a long way to avoid forking processes there. What is 10x faster on Linux despite of forking a process may not be so on Windows.

(I'm not using bash command line completion on Windows, so I can't tell what the effect of your suggested change is on Windows. I hope Gábor can comment on it.)

-- Hannes