revlog: break up compression of large deltas Python's zlib apparently makes an internal copy of strings passed to compress(). To avoid this, compress strings 1M at a time, then join them at the end if the result would be smaller than the original. For initial commits of large but compressible files, this cuts peak memory usage nearly in half.

adding b
   rev    offset  length   base linkrev nodeid       p1           p2
     0         0       3      0       0 1e88685f5dde 000000000000 000000000000