Huge win, compressing a window of delta runs as a unit

Shawn put together a new version of his import utility that packs all of the deltas from a run into a single blob instead of one blob per delta. The idea is to put 10 or more deltas into each delta entry instead of one. The index format would map the 10 sha1's to a single packed delta entry which would be expanded when needed. Note that you probably needed multiple entries out of the delta pack to generate the revision you were looking for so this is no real loss on extraction.

I ran it overnight on mozcvs. If his delta pack code is correct this is a huge win.

One entry per delta - 845,42,0150 Packed deltas - 295,018,474 65% smaller

The effect of packing the deltas is to totally eliminate many of the redundant zlib dictionaries.

This is without using a zlib dictionary which gains another 4% form a 4KB dictionary.