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.
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
pulling from ../source2
pulling from ../source1
requesting all changes
adding changesets
adding manifests
adding file changes
added 10 changesets with 10 changes to 1 files
(run 'hg update' to get a working copy)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
(run 'hg heads' to see heads, 'hg merge' to merge)
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 11 changesets, 11 total revisions