Re: [PATCH] git-p4: improve performance with large files

[Junio C Hamano <gitster@pobox.com>]

Sam Hocevar <sam@zoy.org> writes:

> ... The ideal solution is to use a generator and refactor the commit
> handling as a stream. I am working on that but it involves deeper
> changes, so as I am not sure it will be accepted, I'm providing the
> attached compromise patch first. At least it solves the appaling speed
> issue. I tuned it so that it never uses more than 32 MiB extra memory.
>
> Signed-off-by: Sam Hocevar <sam@zoy.org>
> ---

I do not do p4, but the patch looks obviously correct.  Comments?

>  contrib/fast-import/git-p4 |   10 +++++++++-
>  1 files changed, 9 insertions(+), 1 deletions(-)
>
> diff --git a/contrib/fast-import/git-p4 b/contrib/fast-import/git-p4
> index 3832f60..151ae1c 100755
> --- a/contrib/fast-import/git-p4
> +++ b/contrib/fast-import/git-p4
> @@ -984,11 +984,19 @@ class P4Sync(Command):
>          while j < len(filedata):
>              stat = filedata[j]
>              j += 1
> +            data = []
>              text = ''
>              while j < len(filedata) and filedata[j]['code'] in ('text', 'unicod
> e', 'binary'):
> -                text += filedata[j]['data']
> +                data.append(filedata[j]['data'])
>                  del filedata[j]['data']
> +                # p4 sends 4k chunks, make sure we don't use more than 32 MiB
> +                # of additional memory while rebuilding the file data.
> +                if len(data) > 8192:
> +                    text += ''.join(data)
> +                    data = []
>                  j += 1
> +            text += ''.join(data)
> +            del data
>
>              if not stat.has_key('depotFile'):
>                  sys.stderr.write("p4 print fails with: %s\n" % repr(stat))
>
> -- 
> Sam.
> --
> To unsubscribe from this list: send the line "unsubscribe git" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html