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Re: Should mod_dav_svn/ra_dav support svndiff1? (was: Re: Should 'svnadmin dump --deltas' write svndiff1 diffs?)

From: Daniel Berlin <dberlin_at_dberlin.org>
Date: 2006-02-10 16:35:46 CET

On Fri, 2006-02-10 at 15:31 +0000, Malcolm Rowe wrote:
> On Fri, Feb 10, 2006 at 09:47:21AM -0500, Daniel Berlin wrote:
> > > Though that does make me wonder: did we gain any benefit from making
> > > ra_dav support svndiff1 diffs in the transport, when the whole stream
> > > is almost certainly going to be compressed? Or did we actually make
> > > things worse?
> >
> > It depends on a lot of factors :).
> >
>
> Sure. We really need to measure it :)
>
> > IIRC, isn't the data sent base64 encoded by us beforehand anyway?
> >
>
> Er, not entirely sure. I think that either we or Neon base64 the
> binary blob before transmission, yes. So that would mean that we need
> to determine whether
>
> (((svndiff ins. || svndiff data) => base64) || plaintext) => zlib
>
> was significantly worse or better than
>
> (((svndiff ins. || svndiff data => zlib) => base64) || plaintext) => zlib
>
> ... (or something like that, anyway)

>
> _If_ (big if) the tests I performed with 'dump --deltas' are in any
> way representative, we'll actually send more data in the second case,
> and burn more CPU time, too.

Possibly, and if so, we should definitely turn it off.

It was originally intended as an on-disk format anyway, the fact that we
transmit it over the wire is just kinda gravy.

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Received on Fri Feb 10 16:36:29 2006

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