##// 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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request.py
134 lines | 5.0 KiB | text/x-python | PythonLexer
# hgweb/request.py - An http request from either CGI or the standalone server.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import socket, cgi, errno
from mercurial import util
from common import ErrorResponse, statusmessage, HTTP_NOT_MODIFIED
shortcuts = {
'cl': [('cmd', ['changelog']), ('rev', None)],
'sl': [('cmd', ['shortlog']), ('rev', None)],
'cs': [('cmd', ['changeset']), ('node', None)],
'f': [('cmd', ['file']), ('filenode', None)],
'fl': [('cmd', ['filelog']), ('filenode', None)],
'fd': [('cmd', ['filediff']), ('node', None)],
'fa': [('cmd', ['annotate']), ('filenode', None)],
'mf': [('cmd', ['manifest']), ('manifest', None)],
'ca': [('cmd', ['archive']), ('node', None)],
'tags': [('cmd', ['tags'])],
'tip': [('cmd', ['changeset']), ('node', ['tip'])],
'static': [('cmd', ['static']), ('file', None)]
}
def normalize(form):
# first expand the shortcuts
for k in shortcuts.iterkeys():
if k in form:
for name, value in shortcuts[k]:
if value is None:
value = form[k]
form[name] = value
del form[k]
# And strip the values
for k, v in form.iteritems():
form[k] = [i.strip() for i in v]
return form
class wsgirequest(object):
def __init__(self, wsgienv, start_response):
version = wsgienv['wsgi.version']
if (version < (1, 0)) or (version >= (2, 0)):
raise RuntimeError("Unknown and unsupported WSGI version %d.%d"
% version)
self.inp = wsgienv['wsgi.input']
self.err = wsgienv['wsgi.errors']
self.threaded = wsgienv['wsgi.multithread']
self.multiprocess = wsgienv['wsgi.multiprocess']
self.run_once = wsgienv['wsgi.run_once']
self.env = wsgienv
self.form = normalize(cgi.parse(self.inp,
self.env,
keep_blank_values=1))
self._start_response = start_response
self.server_write = None
self.headers = []
def __iter__(self):
return iter([])
def read(self, count=-1):
return self.inp.read(count)
def drain(self):
'''need to read all data from request, httplib is half-duplex'''
length = int(self.env.get('CONTENT_LENGTH') or 0)
for s in util.filechunkiter(self.inp, limit=length):
pass
def respond(self, status, type, filename=None, body=None):
if self._start_response is not None:
self.headers.append(('Content-Type', type))
if filename:
filename = (filename.split('/')[-1]
.replace('\\', '\\\\').replace('"', '\\"'))
self.headers.append(('Content-Disposition',
'inline; filename="%s"' % filename))
if body is not None:
self.headers.append(('Content-Length', str(len(body))))
for k, v in self.headers:
if not isinstance(v, str):
raise TypeError('header value must be string: %r' % (v,))
if isinstance(status, ErrorResponse):
self.headers.extend(status.headers)
if status.code == HTTP_NOT_MODIFIED:
# RFC 2616 Section 10.3.5: 304 Not Modified has cases where
# it MUST NOT include any headers other than these and no
# body
self.headers = [(k, v) for (k, v) in self.headers if
k in ('Date', 'ETag', 'Expires',
'Cache-Control', 'Vary')]
status = statusmessage(status.code, status.message)
elif status == 200:
status = '200 Script output follows'
elif isinstance(status, int):
status = statusmessage(status)
self.server_write = self._start_response(status, self.headers)
self._start_response = None
self.headers = []
if body is not None:
self.write(body)
self.server_write = None
def write(self, thing):
if thing:
try:
self.server_write(thing)
except socket.error as inst:
if inst[0] != errno.ECONNRESET:
raise
def writelines(self, lines):
for line in lines:
self.write(line)
def flush(self):
return None
def close(self):
return None
def wsgiapplication(app_maker):
'''For compatibility with old CGI scripts. A plain hgweb() or hgwebdir()
can and should now be used as a WSGI application.'''
application = app_maker()
def run_wsgi(env, respond):
return application(env, respond)
return run_wsgi