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.

#!/bin/sh

echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH

hg init a
cd a
echo a > a
hg ci -Ama

hg qnew a.patch
echo a >> a
hg qrefresh

hg qnew b.patch
echo b > b
hg add b
hg qrefresh

hg qnew c.patch
echo c > c
hg add c
hg qrefresh

hg qgoto a.patch
hg qgoto c.patch
hg qgoto b.patch