log: speed up single file log with hidden revs (
issue4747)
On repos with lots of heads, the filelog() code could spend several
minutes decompressing manifests. This change instead tries to
efficiently scan the changelog for candidates and decompress as few
manifests as possible. This is a regression introduced in 3.3 by the
linkrev adjustment code. Prior to that, filelog was nearly instant.
For the repo in the bug report, this improves time of a simple log
command from ~3 minutes to ~.5 seconds, a 360x speedup.
For the main Mercurial repo, a log of commands.py slows down from
1.14s to 1.45s, a 27% slowdown. This is still faster than the file()
revset, which takes 2.1 seconds.
revlog.parseindex must be able to parse the index file even if
an index entry is split between two 64k blocks. The ideal test
would be to create an index file with inline data where
64k < size < 64k + 64 (64k is the size of the read buffer, 64 is
the size of an index entry) and with an index entry starting right
before the 64k block boundary, and try to read it.
We approximate that by reducing the read buffer to 1 byte.
$ hg init a
$ cd a
$ echo abc > foo
$ hg add foo
$ hg commit -m 'add foo'
$ echo >> foo
$ hg commit -m 'change foo'
$ hg log -r 0:
changeset: 0:7c31755bf9b5
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: add foo
changeset: 1:26333235a41c
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: change foo
$ cat >> test.py << EOF
> from mercurial import changelog, scmutil
> from mercurial.node import *
>
> class singlebyteread(object):
> def __init__(self, real):
> self.real = real
>
> def read(self, size=-1):
> if size == 65536:
> size = 1
> return self.real.read(size)
>
> def __getattr__(self, key):
> return getattr(self.real, key)
>
> def opener(*args):
> o = scmutil.opener(*args)
> def wrapper(*a):
> f = o(*a)
> return singlebyteread(f)
> return wrapper
>
> cl = changelog.changelog(opener('.hg/store'))
> print len(cl), 'revisions:'
> for r in cl:
> print short(cl.node(r))
> EOF
$ python test.py
2 revisions:
7c31755bf9b5
26333235a41c
$ cd ..
#if no-pure
Test SEGV caused by bad revision passed to reachableroots() (issue4775):
$ cd a
$ python <<EOF
> from mercurial import changelog, scmutil
> cl = changelog.changelog(scmutil.vfs('.hg/store'))
> print 'good heads:'
> for head in [0, len(cl) - 1, -1]:
> print'%s: %r' % (head, cl.reachableroots(0, [head], [0]))
> print 'bad heads:'
> for head in [len(cl), 10000, -2, -10000, None]:
> print '%s:' % head,
> try:
> cl.reachableroots(0, [head], [0])
> print 'uncaught buffer overflow?'
> except (IndexError, TypeError) as inst:
> print inst
> print 'good roots:'
> for root in [0, len(cl) - 1, -1]:
> print '%s: %r' % (root, cl.reachableroots(root, [len(cl) - 1], [root]))
> print 'out-of-range roots are ignored:'
> for root in [len(cl), 10000, -2, -10000]:
> print '%s: %r' % (root, cl.reachableroots(root, [len(cl) - 1], [root]))
> print 'bad roots:'
> for root in [None]:
> print '%s:' % root,
> try:
> cl.reachableroots(root, [len(cl) - 1], [root])
> print 'uncaught error?'
> except TypeError as inst:
> print inst
> EOF
good heads:
0: [0]
1: [0]
-1: []
bad heads:
2: head out of range
10000: head out of range
-2: head out of range
-10000: head out of range
None: an integer is required
good roots:
0: [0]
1: [1]
-1: [-1]
out-of-range roots are ignored:
2: []
10000: []
-2: []
-10000: []
bad roots:
None: an integer is required
$ cd ..
Test corrupted p1/p2 fields that could cause SEGV at parsers.c:
$ mkdir invalidparent
$ cd invalidparent
$ hg clone --pull -q --config phases.publish=False ../a limit
$ hg clone --pull -q --config phases.publish=False ../a segv
$ rm -R limit/.hg/cache segv/.hg/cache
$ python <<EOF
> data = open("limit/.hg/store/00changelog.i", "rb").read()
> for n, p in [('limit', '\0\0\0\x02'), ('segv', '\0\x01\0\0')]:
> # corrupt p1 at rev0 and p2 at rev1
> d = data[:24] + p + data[28:127 + 28] + p + data[127 + 32:]
> open(n + "/.hg/store/00changelog.i", "wb").write(d)
> EOF
$ hg debugindex -f1 limit/.hg/store/00changelog.i
rev flag offset length size base link p1 p2 nodeid
0 0000 0 63 62 0 0 2 -1 7c31755bf9b5
1 0000 63 66 65 1 1 0 2 26333235a41c
$ hg debugindex -f1 segv/.hg/store/00changelog.i
rev flag offset length size base link p1 p2 nodeid
0 0000 0 63 62 0 0 65536 -1 7c31755bf9b5
1 0000 63 66 65 1 1 0 65536 26333235a41c
$ cat <<EOF > test.py
> import sys
> from mercurial import changelog, scmutil
> cl = changelog.changelog(scmutil.vfs(sys.argv[1]))
> n0, n1 = cl.node(0), cl.node(1)
> ops = [
> ('reachableroots',
> lambda: cl.index.reachableroots2(0, [1], [0], False)),
> ('compute_phases_map_sets', lambda: cl.computephases([[0], []])),
> ('index_headrevs', lambda: cl.headrevs()),
> ('find_gca_candidates', lambda: cl.commonancestorsheads(n0, n1)),
> ('find_deepest', lambda: cl.ancestor(n0, n1)),
> ]
> for l, f in ops:
> print l + ':',
> try:
> f()
> print 'uncaught buffer overflow?'
> except ValueError, inst:
> print inst
> EOF
$ python test.py limit/.hg/store
reachableroots: parent out of range
compute_phases_map_sets: parent out of range
index_headrevs: parent out of range
find_gca_candidates: parent out of range
find_deepest: parent out of range
$ python test.py segv/.hg/store
reachableroots: parent out of range
compute_phases_map_sets: parent out of range
index_headrevs: parent out of range
find_gca_candidates: parent out of range
find_deepest: parent out of range
$ cd ..
#endif