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
# @ (34) head
# |
# | o (33) head
# | |
# o | (32) expand
# |\ \
# | o \ (31) expand
# | |\ \
# | | o \ (30) expand
# | | |\ \
# | | | o | (29) regular commit
# | | | | |
# | | o | | (28) merge zero known
# | | |\ \ \
# o | | | | | (27) collapse
# |/ / / / /
# | | o---+ (26) merge one known; far right
# | | | | |
# +---o | | (25) merge one known; far left
# | | | | |
# | | o | | (24) merge one known; immediate right
# | | |\| |
# | | o | | (23) merge one known; immediate left
# | |/| | |
# +---o---+ (22) merge two known; one far left, one far right
# | | / /
# o | | | (21) expand
# |\ \ \ \
# | o---+-+ (20) merge two known; two far right
# | / / /
# o | | | (19) expand
# |\ \ \ \
# +---+---o (18) merge two known; two far left
# | | | |
# | o | | (17) expand
# | |\ \ \
# | | o---+ (16) merge two known; one immediate right, one near right
# | | |/ /
# o | | | (15) expand
# |\ \ \ \
# | o-----+ (14) merge two known; one immediate right, one far right
# | |/ / /
# o | | | (13) expand
# |\ \ \ \
# +---o | | (12) merge two known; one immediate right, one far left
# | | |/ /
# | o | | (11) expand
# | |\ \ \
# | | o---+ (10) merge two known; one immediate left, one near right
# | |/ / /
# o | | | (9) expand
# |\ \ \ \
# | o-----+ (8) merge two known; one immediate left, one far right
# |/ / / /
# o | | | (7) expand
# |\ \ \ \
# +---o | | (6) merge two known; one immediate left, one far left
# | |/ / /
# | o | | (5) expand
# | |\ \ \
# | | o | | (4) merge two known; one immediate left, one immediate right
# | |/|/ /
# | o / / (3) collapse
# |/ / /
# o / / (2) collapse
# |/ /
# o / (1) collapse
# |/
# o (0) root
set -e
commit()
{
rev=$1
msg=$2
shift 2
if [ "$#" -gt 0 ]; then
hg debugsetparents "$@"
fi
echo $rev > $rev
hg add $rev
hg ci -d "$rev 0" -m "($rev) $msg"
}
echo "[extensions]" >> $HGRCPATH
echo "graphlog=" >> $HGRCPATH
echo % init
hg init repo
cd repo
echo % empty repo
hg glog
echo % building tree
commit 0 "root"
commit 1 "collapse" 0
commit 2 "collapse" 1
commit 3 "collapse" 2
commit 4 "merge two known; one immediate left, one immediate right" 1 3
commit 5 "expand" 3 4
commit 6 "merge two known; one immediate left, one far left" 2 5
commit 7 "expand" 2 5
commit 8 "merge two known; one immediate left, one far right" 0 7
commit 9 "expand" 7 8
commit 10 "merge two known; one immediate left, one near right" 0 6
commit 11 "expand" 6 10
commit 12 "merge two known; one immediate right, one far left" 1 9
commit 13 "expand" 9 11
commit 14 "merge two known; one immediate right, one far right" 0 12
commit 15 "expand" 13 14
commit 16 "merge two known; one immediate right, one near right" 0 1
commit 17 "expand" 12 16
commit 18 "merge two known; two far left" 1 15
commit 19 "expand" 15 17
commit 20 "merge two known; two far right" 0 18
commit 21 "expand" 19 20
commit 22 "merge two known; one far left, one far right" 18 21
commit 23 "merge one known; immediate left" 1 22
commit 24 "merge one known; immediate right" 0 23
commit 25 "merge one known; far left" 21 24
commit 26 "merge one known; far right" 18 25
commit 27 "collapse" 21
commit 28 "merge zero known" 1 26
commit 29 "regular commit" 0
commit 30 "expand" 28 29
commit 31 "expand" 21 30
commit 32 "expand" 27 31
commit 33 "head" 18
commit 34 "head" 32
echo % glog -q
hg glog -q
echo % glog
hg glog
echo % unused arguments
hg glog -q foo || echo failed