Re: [PATCH 4/8] git-remote-mediawiki: get rid of O(N^2) loop

Junio C Hamano [off-list ref] writes:

Matthieu Moy [off-list ref] writes:

quoted

The algorithm to find a path from the local revision to the remote one
was calling "git rev-list" and parsing its output N times. Run rev-list
only once, and fill a hashtable with the result to optimize the body of
the loop.

Good thinking.  I wonder if it would further reduce the overhead if
you stop using --children and do this using --parents instead, as
you will be reading the parsed_sha1..local range either way yourself
anyway.

It is possible, yes. I'll resend a version with --parents, but this
probably doesn't change the performance much: what we really need is for
Git to prune dead-ends in the subgraph, to make sure we find a path
without having to backtrack (i.e. we need parent rewriting history
simplification), so Git has to do something a bit clever anyway.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/