branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init repo
$ cd repo
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ echo y > y
$ echo z > z
$ hg commit -qAm xy
$ cd ..
$ cat > cacheprocess-logger.py <<EOF
> import os
> import shutil
> import sys
> f = open('$TESTTMP/cachelog.log', 'w')
> srccache = os.path.join('$TESTTMP', 'oldhgcache')
> def log(message):
> f.write(message)
> f.flush()
> destcache = sys.argv[-1]
> try:
> while True:
> cmd = sys.stdin.readline().strip()
> log('got command %r\n' % cmd)
> if cmd == 'exit':
> sys.exit(0)
> elif cmd == 'get':
> count = int(sys.stdin.readline())
> log('client wants %r blobs\n' % count)
> wants = []
> for _ in range(count):
> key = sys.stdin.readline()[:-1]
> wants.append(key)
> if '\0' in key:
> _, key = key.split('\0')
> srcpath = os.path.join(srccache, key)
> if os.path.exists(srcpath):
> dest = os.path.join(destcache, key)
> destdir = os.path.dirname(dest)
> if not os.path.exists(destdir):
> os.makedirs(destdir)
> shutil.copyfile(srcpath, dest)
> else:
> # report a cache miss
> sys.stdout.write(key + '\n')
> sys.stdout.write('0\n')
> for key in sorted(wants):
> log('requested %r\n' % key)
> sys.stdout.flush()
> elif cmd == 'set':
> raise Exception('todo writing')
> else:
> raise Exception('unknown command! %r' % cmd)
> except Exception as e:
> log('Exception! %s\n' % e)
> raise
> EOF
$ cat >> $HGRCPATH <<EOF
> [remotefilelog]
> cacheprocess = "$PYTHON" $TESTTMP/cacheprocess-logger.py
> EOF
Test cache keys and cache misses.
$ hgcloneshallow ssh://user@dummy/repo clone -q
3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
$ cat cachelog.log
got command 'get'
client wants 3 blobs
requested 'master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0'
requested 'master/39/5df8f7c51f007019cb30201c49e884b46b92fa/69a1b67522704ec122181c0890bd16e9d3e7516a'
requested 'master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca'
got command 'set'
Exception! todo writing
Test cache hits.
$ mv hgcache oldhgcache
$ rm cachelog.log
$ hgcloneshallow ssh://user@dummy/repo clone-cachehit -q
3 files fetched over 1 fetches - (0 misses, 100.00% hit ratio) over *s (glob)
$ cat cachelog.log | grep -v exit
got command 'get'
client wants 3 blobs
requested 'master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0'
requested 'master/39/5df8f7c51f007019cb30201c49e884b46b92fa/69a1b67522704ec122181c0890bd16e9d3e7516a'
requested 'master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca'
$ cat >> $HGRCPATH <<EOF
> [remotefilelog]
> cacheprocess.includepath = yes
> EOF
Test cache keys and cache misses with includepath.
$ rm -r hgcache oldhgcache
$ rm cachelog.log
$ hgcloneshallow ssh://user@dummy/repo clone-withpath -q
3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
$ cat cachelog.log
got command 'get'
client wants 3 blobs
requested 'x\x00master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0'
requested 'y\x00master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca'
requested 'z\x00master/39/5df8f7c51f007019cb30201c49e884b46b92fa/69a1b67522704ec122181c0890bd16e9d3e7516a'
got command 'set'
Exception! todo writing
Test cache hits with includepath.
$ mv hgcache oldhgcache
$ rm cachelog.log
$ hgcloneshallow ssh://user@dummy/repo clone-withpath-cachehit -q
3 files fetched over 1 fetches - (0 misses, 100.00% hit ratio) over *s (glob)
$ cat cachelog.log | grep -v exit
got command 'get'
client wants 3 blobs
requested 'x\x00master/11/f6ad8ec52a2984abaafd7c3b516503785c2072/1406e74118627694268417491f018a4a883152f0'
requested 'y\x00master/95/cb0bfd2977c761298d9624e4b4d4c72a39974a/076f5e2225b3ff0400b98c92aa6cdf403ee24cca'
requested 'z\x00master/39/5df8f7c51f007019cb30201c49e884b46b92fa/69a1b67522704ec122181c0890bd16e9d3e7516a'