From: Jon Smirl Date: Sat, 02 Sep 2006 14:20:49 GMT Subject: Re: Mozilla .git tree Message-ID: <9e4733910609020720w3633aa0cq5016fb1e223fc4cb@mail.gmail.com> In-Reply-To: <7vveo6zfx0.fsf@assigned-by-dhcp.cox.net> On 9/2/06, Junio C Hamano wrote: > Shawn Pearce writes: > > > Using a 28 byte index entry instead of a 32 byte index entry means > > the Mozilla historical pack index will only be 52.4 MiB rather than > > the slightly larger 59.9 MiB. > > Yup, that was one consideration. One small worry is we will be > placing u64 at 4-byte alignment by using 28-byte entries but I > think that is Ok. If you're going to redo the pack formats another big win for the Mozilla pack is to convert pack internal sha1 references into file offsets.within the pack. Doing that will take around 30MB off from the Mozilla pack size. sha1's are not compressible so this is a direct savings. This might reduce memory usage too. The index is only needed to get the initial object from the pack. Since index use is lighter it could just be open/closed when needed. You could also introduce a zlib dictionary object into the format and just leave it empty for now. -- Jon Smirl jonsmirl@gmail.com -- VGER BF report: U 0.5