From: A Large Angry SCM Date: Sun, 26 Apr 2009 17:33:36 GMT Subject: Re: Google Code: Support for Mercurial and Analysis of Git and Mercurial Message-ID: <49F49AF0.1020301@gmail.com> In-Reply-To: Johannes Schindelin wrote: > Hi, > > On Sun, 26 Apr 2009, A Large Angry SCM wrote: > >> Another important criteria was which, both or neither of Git and Hg >> would actually work and perform well on top of Google Code's underling >> storage system and except to mention they would be using Bigtable, the >> report did not discuss this. Git on top of Bigtable will not perform >> well. > > Actually, did we not arrive at the conclusion that it could perform well > at least with the filesystem layer on top of big table, but even better if > the big tables stored certain chunks (not really all that different from > the chunks needed for mirror-sync!)? > > Back when I discussed this with a Googler, it was all too obvious that > they are not interested (and in the meantime I understand why, see my > other mail). > I don't remember the mirror-sync discussion. But I do remember that when the discussion turned to implementing a filesystem on top of Bigtable that would not cause performance problems for Git, my response was that you'd still be much better off going to GFS directly instead of faking a filesystem on top of Bigtable without all of the Bigtable limitations. Bigtable _is_ appealing to implement the Git object store on. It's too bad the latency in Bigtable would make it horribly slow.