branchmap: update rev-branch-cache incrementally
Historically, the revision to branch mapping cache was updated on demand
and shared via bundle2 to avoid the cost of rebuilding on first use.
Use the new `register_changeset` callback and update rbc directly on
every change. Make the transfer of the bundle part redundant, but keep
it for the moment to avoid the test churn.
Over all, "hg unbundle" for large bundles is less than 1.8% slower for
different larger repositories and that seems to a reasonable trade off.
Differential Revision: https://phab.mercurial-scm.org/D9781
====================================
Test delta choice with sparse revlog
====================================
Sparse-revlog usually shows the most gain on Manifest. However, it is simpler
to general an appropriate file, so we test with a single file instead. The
goal is to observe intermediate snapshot being created.
We need a large enough file. Part of the content needs to be replaced
repeatedly while some of it changes rarely.
$ bundlepath="$TESTDIR/artifacts/cache/big-file-churn.hg"
$ expectedhash=`cat "$bundlepath".md5`
#if slow
$ if [ ! -f "$bundlepath" ]; then
> "$TESTDIR"/artifacts/scripts/generate-churning-bundle.py > /dev/null
> fi
#else
$ if [ ! -f "$bundlepath" ]; then
> echo 'skipped: missing artifact, run "'"$TESTDIR"'/artifacts/scripts/generate-churning-bundle.py"'
> exit 80
> fi
#endif
$ currenthash=`f -M "$bundlepath" | cut -d = -f 2`
$ if [ "$currenthash" != "$expectedhash" ]; then
> echo 'skipped: outdated artifact, md5 "'"$currenthash"'" expected "'"$expectedhash"'" run "'"$TESTDIR"'/artifacts/scripts/generate-churning-bundle.py"'
> exit 80
> fi
$ cat >> $HGRCPATH << EOF
> [format]
> sparse-revlog = yes
> maxchainlen = 15
> [storage]
> revlog.optimize-delta-parent-choice = yes
> revlog.reuse-external-delta = no
> EOF
$ hg init sparse-repo
$ cd sparse-repo
$ hg unbundle $bundlepath
adding changesets
adding manifests
adding file changes
added 5001 changesets with 5001 changes to 1 files (+89 heads)
new changesets 9706f5af64f4:d9032adc8114 (5001 drafts)
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg up
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "d9032adc8114: commit #5000"
89 other heads for branch "default"
$ hg log --stat -r 0:3
changeset: 0:9706f5af64f4
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: initial commit
SPARSE-REVLOG-TEST-FILE | 10500 ++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 10500 insertions(+), 0 deletions(-)
changeset: 1:724907deaa5e
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit #1
SPARSE-REVLOG-TEST-FILE | 1068 +++++++++++++++++++++++-----------------------
1 files changed, 534 insertions(+), 534 deletions(-)
changeset: 2:62c41bce3e5d
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit #2
SPARSE-REVLOG-TEST-FILE | 1068 +++++++++++++++++++++++-----------------------
1 files changed, 534 insertions(+), 534 deletions(-)
changeset: 3:348a9cbd6959
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit #3
SPARSE-REVLOG-TEST-FILE | 1068 +++++++++++++++++++++++-----------------------
1 files changed, 534 insertions(+), 534 deletions(-)
$ f -s .hg/store/data/*.d
.hg/store/data/_s_p_a_r_s_e-_r_e_v_l_o_g-_t_e_s_t-_f_i_l_e.d: size=63327412
$ hg debugrevlog *
format : 1
flags : generaldelta
revisions : 5001
merges : 625 (12.50%)
normal : 4376 (87.50%)
revisions : 5001
empty : 0 ( 0.00%)
text : 0 (100.00%)
delta : 0 (100.00%)
snapshot : 383 ( 7.66%)
lvl-0 : 3 ( 0.06%)
lvl-1 : 20 ( 0.40%)
lvl-2 : 68 ( 1.36%)
lvl-3 : 112 ( 2.24%)
lvl-4 : 180 ( 3.60%)
deltas : 4618 (92.34%)
revision size : 63327412
snapshot : 9886710 (15.61%)
lvl-0 : 603104 ( 0.95%)
lvl-1 : 1559991 ( 2.46%)
lvl-2 : 2295592 ( 3.62%)
lvl-3 : 2531199 ( 4.00%)
lvl-4 : 2896824 ( 4.57%)
deltas : 53440702 (84.39%)
chunks : 5001
0x78 (x) : 5001 (100.00%)
chunks size : 63327412
0x78 (x) : 63327412 (100.00%)
avg chain length : 9
max chain length : 15
max chain reach : 28248745
compression ratio : 27
uncompressed data size (min/max/avg) : 346468 / 346472 / 346471
full revision size (min/max/avg) : 201008 / 201050 / 201034
inter-snapshot size (min/max/avg) : 11596 / 168150 / 24430
level-1 (min/max/avg) : 16653 / 168150 / 77999
level-2 (min/max/avg) : 12951 / 85595 / 33758
level-3 (min/max/avg) : 11608 / 43029 / 22599
level-4 (min/max/avg) : 11596 / 21632 / 16093
delta size (min/max/avg) : 10649 / 107163 / 11572
deltas against prev : 3910 (84.67%)
where prev = p1 : 3910 (100.00%)
where prev = p2 : 0 ( 0.00%)
other : 0 ( 0.00%)
deltas against p1 : 648 (14.03%)
deltas against p2 : 60 ( 1.30%)
deltas against other : 0 ( 0.00%)