git-commit-vandalism/t/perf/p5303-many-packs.sh
Eric Sunshine db5875aa9f t0000-t3999: detect and signal failure within loop
Failures within `for` and `while` loops can go unnoticed if not detected
and signaled manually since the loop itself does not abort when a
contained command fails, nor will a failure necessarily be detected when
the loop finishes since the loop returns the exit code of the last
command it ran on the final iteration, which may not be the command
which failed. Therefore, detect and signal failures manually within
loops using the idiom `|| return 1` (or `|| exit 1` within subshells).

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-13 10:29:48 -08:00

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#!/bin/sh
test_description='performance with large numbers of packs'
. ./perf-lib.sh
test_perf_large_repo
# A real many-pack situation would probably come from having a lot of pushes
# over time. We don't know how big each push would be, but we can fake it by
# just walking the first-parent chain and having every 5 commits be their own
# "push". This isn't _entirely_ accurate, as real pushes would have some
# duplicate objects due to thin-pack fixing, but it's a reasonable
# approximation.
#
# And then all of the rest of the objects can go in a single packfile that
# represents the state before any of those pushes (actually, we'll generate
# that first because in such a setup it would be the oldest pack, and we sort
# the packs by reverse mtime inside git).
repack_into_n () {
rm -rf staging &&
mkdir staging &&
git rev-list --first-parent HEAD |
perl -e '
my $n = shift;
while (<>) {
last unless @commits < $n;
push @commits, $_ if $. % 5 == 1;
}
print reverse @commits;
' "$1" >pushes &&
# create base packfile
base_pack=$(
head -n 1 pushes |
git pack-objects --delta-base-offset --revs staging/pack
) &&
test_export base_pack &&
# create an empty packfile
empty_pack=$(git pack-objects staging/pack </dev/null) &&
test_export empty_pack &&
# and then incrementals between each pair of commits
last= &&
while read rev
do
if test -n "$last"; then
{
echo "$rev" &&
echo "^$last"
} |
git pack-objects --delta-base-offset --revs \
staging/pack || return 1
fi
last=$rev
done <pushes &&
(
find staging -type f -name 'pack-*.pack' |
xargs -n 1 basename | grep -v "$base_pack" &&
printf "^pack-%s.pack\n" $base_pack
) >stdin.packs
# and install the whole thing
rm -f .git/objects/pack/* &&
mv staging/* .git/objects/pack/
}
# Pretend we just have a single branch and no reflogs, and that everything is
# in objects/pack; that makes our fake pack-building via repack_into_n()
# much simpler.
test_expect_success 'simplify reachability' '
tip=$(git rev-parse --verify HEAD) &&
git for-each-ref --format="option no-deref%0adelete %(refname)" |
git update-ref --stdin &&
rm -rf .git/logs &&
git update-ref refs/heads/master $tip &&
git symbolic-ref HEAD refs/heads/master &&
git repack -ad
'
for nr_packs in 1 50 1000
do
test_expect_success "create $nr_packs-pack scenario" '
repack_into_n $nr_packs
'
test_perf "rev-list ($nr_packs)" '
git rev-list --objects --all >/dev/null
'
test_perf "abbrev-commit ($nr_packs)" '
git rev-list --abbrev-commit HEAD >/dev/null
'
# This simulates the interesting part of the repack, which is the
# actual pack generation, without smudging the on-disk setup
# between trials.
test_perf "repack ($nr_packs)" '
GIT_TEST_FULL_IN_PACK_ARRAY=1 \
git pack-objects --keep-true-parents \
--honor-pack-keep --non-empty --all \
--reflog --indexed-objects --delta-base-offset \
--stdout </dev/null >/dev/null
'
test_perf "repack with kept ($nr_packs)" '
git pack-objects --keep-true-parents \
--keep-pack=pack-$empty_pack.pack \
--honor-pack-keep --non-empty --all \
--reflog --indexed-objects --delta-base-offset \
--stdout </dev/null >/dev/null
'
test_perf "repack with --stdin-packs ($nr_packs)" '
git pack-objects \
--keep-true-parents \
--stdin-packs \
--non-empty \
--delta-base-offset \
--stdout <stdin.packs >/dev/null
'
done
# Measure pack loading with 10,000 packs.
test_expect_success 'generate lots of packs' '
for i in $(test_seq 10000); do
echo "blob" &&
echo "data <<EOF" &&
echo "blob $i" &&
echo "EOF" &&
echo "checkpoint" || return 1
done |
git -c fastimport.unpackLimit=0 fast-import
'
# The purpose of this test is to evaluate load time for a large number
# of packs while doing as little other work as possible.
test_perf "load 10,000 packs" '
git rev-parse --verify "HEAD^{commit}"
'
test_done