##// END OF EJS Templates
revlog: change generaldelta delta parent heuristic...
revlog: change generaldelta delta parent heuristic The old generaldelta heuristic was "if p1 (or p2) was closer than the last full text, use it, otherwise use prev". This was problematic when a repo contained multiple branches that were very different. If commits to branch A were pushed, and the last full text was branch B, it would generate a fulltext. Then if branch B was pushed, it would generate another fulltext. The problem is that the last fulltext (and delta'ing against `prev` in general) has no correlation with the contents of the incoming revision, and therefore will always have degenerate cases. According to the blame, that algorithm was chosen to minimize the chain length. Since there is already code that protects against that (the delta-vs-fulltext code), and since it has been improved since the original generaldelta algorithm went in (2011), I believe the chain length criteria will still be preserved. The new algorithm always diffs against p1 (or p2 if it's closer), unless the resulting delta will fail the delta-vs-fulltext check, in which case we delta against prev. Some before and after stats on manifest.d size. internal large repo old heuristic - 2.0 GB new heuristic - 1.2 GB mozilla-central old heuristic - 242 MB new heuristic - 261 MB The regression in mozilla central is due to the new heuristic choosing p2r as the delta when it's closer to the tip. Switching the algorithm to always prefer p1r brings the size back down (242 MB). This is result of the way in which mozilla does merges and pushes, and the result could easily swing the other direction in other repos (depending on if they merge X into Y or Y into X), but will never be as degenerate as before. I future patch will address the regression by introducing an optional, even more aggressive delta heuristic which will knock the mozilla manifest size down dramatically.

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r18552:e8efcc8f stable
r26117:4dc5b51f default
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wsgicgi.py
83 lines | 2.7 KiB | text/x-python | PythonLexer
# hgweb/wsgicgi.py - CGI->WSGI translator
#
# Copyright 2006 Eric Hopper <hopper@omnifarious.org>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# This was originally copied from the public domain code at
# http://www.python.org/dev/peps/pep-0333/#the-server-gateway-side
import os, sys
from mercurial import util
from mercurial.hgweb import common
def launch(application):
util.setbinary(sys.stdin)
util.setbinary(sys.stdout)
environ = dict(os.environ.iteritems())
environ.setdefault('PATH_INFO', '')
if environ.get('SERVER_SOFTWARE', '').startswith('Microsoft-IIS'):
# IIS includes script_name in PATH_INFO
scriptname = environ['SCRIPT_NAME']
if environ['PATH_INFO'].startswith(scriptname):
environ['PATH_INFO'] = environ['PATH_INFO'][len(scriptname):]
stdin = sys.stdin
if environ.get('HTTP_EXPECT', '').lower() == '100-continue':
stdin = common.continuereader(stdin, sys.stdout.write)
environ['wsgi.input'] = stdin
environ['wsgi.errors'] = sys.stderr
environ['wsgi.version'] = (1, 0)
environ['wsgi.multithread'] = False
environ['wsgi.multiprocess'] = True
environ['wsgi.run_once'] = True
if environ.get('HTTPS', 'off').lower() in ('on', '1', 'yes'):
environ['wsgi.url_scheme'] = 'https'
else:
environ['wsgi.url_scheme'] = 'http'
headers_set = []
headers_sent = []
out = sys.stdout
def write(data):
if not headers_set:
raise AssertionError("write() before start_response()")
elif not headers_sent:
# Before the first output, send the stored headers
status, response_headers = headers_sent[:] = headers_set
out.write('Status: %s\r\n' % status)
for header in response_headers:
out.write('%s: %s\r\n' % header)
out.write('\r\n')
out.write(data)
out.flush()
def start_response(status, response_headers, exc_info=None):
if exc_info:
try:
if headers_sent:
# Re-raise original exception if headers sent
raise exc_info[0](exc_info[1], exc_info[2])
finally:
exc_info = None # avoid dangling circular ref
elif headers_set:
raise AssertionError("Headers already set!")
headers_set[:] = [status, response_headers]
return write
content = application(environ, start_response)
try:
for chunk in content:
write(chunk)
if not headers_sent:
write('') # send headers now if body was empty
finally:
getattr(content, 'close', lambda : None)()