[python-committers] Survey about DVCSs compared to svn

[Georg Brandl]

Antoine Pitrou schrieb:
> Le jeudi 26 février 2009 à 17:10 +0100, M.-A. Lemburg a écrit :
>> This is probably a matter of Internet connection bandwidth then.
> 
> Not really.
> To give a point of comparison, when I clone (using Mercurial) the Python
> trunk at http://code.python.org/hg/trunk, it takes 2 minutes 50 seconds.
> That's for the whole trunk history from 1990 to today, and bandwidth is
> around 500 KB/s (sustained) during the downloading.
> 
> So, having svnmerge take one minute or more from a machine hosted at the
> same place as code.python.org points to a really slow merge
> implementation IMO.
> 
>> I have no idea how much data gets transferred, but it doesn't
>> "feel" slow.
> 
> It definitely feels slow when you merge from e.g. trunk to py3k.

It doesn't only *feel* slow, it *is* slow.  And not only compared to merging
with a DVCS, which doesn't need network.  Half a minute to merge a three-line
change is not productive.

Not to mention the various other problems with svnmerge, e.g. having to pack
several merges into "batch" commits which then are atomic on the merged-to
branch (which bites us merging from 3.1 to 3.0).  (And no, merging each commit
individually is not an option, because it takes even *longer*.)

Frankly, there are very few people who routinely (like Benjamin) or even only
sometimes (like me) merge larger amounts of stuff between our four branches.
While that's no surprise, given how clumsy svnmerge makes it, others shouldn't
just dismiss the merging problem with "we have svnmerge".

Georg

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