From: Shawn O. Pearce Date: Sat, 12 Sep 2009 18:11:50 GMT Subject: Re: [PATCHv5 00/14] git notes Message-ID: <20090912181150.GN1033@spearce.org> In-Reply-To: <200909121750.00733.johan@herland.net> Johan Herland wrote: > Shawn, do you have any additional defence for the date-based fanout? No. The only defense I have for it is "it sounds like a nice theory given access patterns", and the note about memory usage you made, but which I clipped to keep this email shorter. :-) It was only a theory I tossed out there in a back-seat-driver sort of way. Your results show my hunch was correct, it may help. But they also say it may not help enough to justify the complexity, so I now agree with you that SHA-1 fan out may be good enough. > Are > there untested reasonable scenarios that would show the benefits of date- > based fanout? I don't think there are, your tests were pretty good at covering things. > How does the plan for notes usage in your code-review thingy > compare to my test scenario? I think your tests may still have been too low in volume, 115k notes isn't a lot. Based on the distributions I was looking at before, I could be seeing a growth of >100k notes/year. Ask me again in 5 years if 115k notes is a lot. :-) But we all know that SHA-1 distributes data quite well, so the SHA-1 fan-out may just need to change from 2_38 to 2_2_2_34 (or something) to handle that larger volume. -- Shawn.