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Re: suboptimal behavior of fast-import in some cases with "from"

From
Junio C Hamano <gitster@pobox.com>
Date
Jul 6, 2015, 22:54 UTC
Message-ID
<xmqq4mlgzyl0.fsf@gitster.dls.corp.google.com>
In-Reply-To
<20150706220746.GA29367@glandium.org>
Mike Hommey <mh@glandium.org> writes:
> One of the first things parse_from does is unconditionally throw away
> the tree for the given branch, and then the "from" tree is loaded. So
> when the "from" commit is the current head of the branch, that make
> fast-import do more work than necessary.

If it is very common that the next commit the input stream wants to create is often on top of the commit that was just created, and if it is very common that the input stream producer knows what the commit object name of the commit that was just created, then optimising for that case does not sound too bad. It really depends on two factors:

 - How likely is it that other people make the same mistake?
 - How bad the damage to parse_from() would be if we wanted to
   optimize for this case?
Previous: Mike HommeyNext: Mike Hommey
Message 2 of 9 in “suboptimal behavior of fast-import in some cases with "from"”
  1. Mike HommeyJul 6, 2015
  2. Junio C HamanoJul 6, 2015
  3. Mike HommeyJul 9, 2015
  4. Mike HommeyJul 9, 2015
  5. fast-import: Do less work when given "from" matches current branch headMike Hommey, Jul 9, 2015
  6. Junio C HamanoJul 9, 2015
  7. Mike HommeyJul 9, 2015
  8. Junio C HamanoJul 9, 2015
  9. Junio C HamanoJul 9, 2015

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