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From: "Shawn O. Pearce" <spearce@spearce•org>
To: Sebastian Bober <sbober@servercare•de>
Cc: Sverre Rabbelier <srabbelier@gmail•com>,
	Richard Hartmann <richih.mailinglist@gmail•com>,
	Git List <git@vger•kernel.org>,
	Avery Pennarun <apenwarr@gmail•com>,
	Nicolas Pitre <nico@fluxnic•net>, Sam Vilain <sam@vilain•net>
Subject: Re: Git import of the recent full enwiki dump
Date: Fri, 16 Apr 2010 17:53:42 -0700	[thread overview]
Message-ID: <20100417005342.GA8475@spearce.org> (raw)
In-Reply-To: <20100417004852.GA32053@post.servercare.de>

Sebastian Bober <sbober@servercare•de> wrote:
> The question would be, how the commits and the trees are laid out.
> If every wiki revision shall be a git commit, then we'd need to handle
> 300M commits. And we have 19M wiki pages (that would be files). The tree
> objects would be very large and git-fast-import would crawl.
> 
> Some tests with the german wikipedia have shown that importing the blobs
> is doable on normal hardware. Getting the trees and commits into git
> was not possible up to now, as fast-import was just to slow (and getting
> slower after 1M commits).

Well, to be fair to fast-import, its tree handling code is linear
scan based, because that's how any other part of Git handles trees.

If you just toss all 19M wiki pages into a single top level tree,
that's going to take a very long time to locate the wiki page
talking about Zoos.

> I had the idea of having an importer that would just handle this special
> case (1 file change per commit), but didn't get around to try that yet.

Really, fast-import should be able to handle this well, assuming you
aren't just tossing all 19M files into a single massive directory
and hoping for the best.  Because *any* program working on that
sort of layout will need to spit out the 19M entry tree object on
each and every commit, just so it can compute the SHA-1 checksum
to get the tree name for the commit.

-- 
Shawn.

  reply	other threads:[~2010-04-17  1:02 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-16 23:47 Git import of the recent full enwiki dump Richard Hartmann
2010-04-17  0:19 ` Sverre Rabbelier
2010-04-17  0:48   ` Sebastian Bober
2010-04-17  0:53     ` Shawn O. Pearce [this message]
2010-04-17  1:01       ` Sebastian Bober
2010-04-17  1:44         ` [spf:guess] " Sam Vilain
2010-04-17  1:58           ` Sebastian Bober
2010-04-17  3:34             ` [spf:guess] " Sam Vilain
2010-04-17  7:48               ` Sebastian Bober
2010-04-17  1:10   ` Richard Hartmann
2010-04-17  1:18     ` Shawn O. Pearce
2010-04-17  1:25     ` Sebastian Bober

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