Mercurial > hg
view mercurial/keepalive.py @ 39506:b66ea3fc3a86
sparse-revlog: set max delta chain length to on thousand
The new snapshot system used in the sparse-revlog case gave us some small size
benefit so far. However its most important property is to gracefully handle
harder limit on delta chainlength.
Long delta chain has a very detrimental impact on read (and write) performance
in revlog. Being able to shorter them provide a great boost. However, shorting
delta used to result significantly lower compression ratio. The intermediate
snapshots effectively suppress most of this effect (even all in some case).
# Effect on the test repository
The repository we use for test is not "realistic" but can still show this in
action using an unreasonably low chain limit. Limiting the chain length show a
sizeable increase but stay under control: +6% for limit=15; +15% for limit=10.
Without the snapshot system the increase is significantly bigger: +45% for
limit=15; +80% for limit=10. Even slightly larger than without delta chain
limit, the resulting size is still smaller than before we started doing
snapshots.
Here is a table for comparison. *Since the repository is not branchy, the
initial sparse-revlog version does not bring much benefit compare to the
non-sparse one):
chain length limit | none | limit=15 | limit=10 |
without sparse-revlog | 62 818 987 | 112 664 615 | 131 222 574 |
without snapshot | 74 365 490 | 108 211 410 | 133 857 764 |
with snapshot | 59 230 936 | 63 002 924 | 68 415 329 |
# Effect On Real Life Repositories
The series provides significant benefits on all kind of repositories.
Using `hg debugupgraderepo -o redeltaparent --run`, we recomputed delta chain
for various repositories with different settings:
- delta chain length: unlimited or 1000 limit
- sparse-revlog: enabled or disabled
- this series: applied or not applied
We can observe multiple types of effect:
- On very branchy repositories:
* The delta chain limit as low impact on the repo size.
* Intermediate snapshot greatly reduces manifest size:
- pypy: -80%
- netbeans: -95%
* The delta chain limit is effective, without a size impact:
- netbeans average: 613 -> 282
- private #1 average: 1 068 -> 307
- On more linear repository:
* Intermediate snapshot limit the impact of delta chain limit:
- mozilla:
without the series: +360%
with the series: +25%
* The delta chain limit provides large improvement:
- mozilla's average chain length:
unlimited: 15 338
limited: 469
* Despite the chain length limit, the manifest size is reduced:
- mercurial: -25%
- mozilla: -30%
It is clear that the use of chains of intermediate snapshots provide large
benefits both in storage size and delta chains quality. We should now switch our
effort toward making sure the write performance are acceptable. Then,
`sparse-revlog` will be a suitable format for all new repository.
# Raw Statistic
* no-sparse: general delta repository not using sparse-revlog
* no-snapshot: sparse-revlog repository not using this series
* snapshot: sparse-revlog repository using this series
mercurial
Manifest Size:
limit | none | 1000
------------|-------------|------------
no-sparse | 8 021 373 | 8 199 366
no-snapshot | 8 103 561 | 8 259 719
snapshot | 6 137 116 | 6 126 433
Manifest Chain length data
limit || none || 1000 ||
value || average | max || average | max ||
------------||---------|---------||---------|---------||
no-sparse || 307 | 1456 || 279 | 1000 ||
no-snapshot || 312 | 1456 || 283 | 1000 ||
snapshot || 248 | 1208 || 241 | 1000 ||
Full Store Size
limit | none | 1000
------------|-------------|------------
no-sparse | 51 013 198 | 51 201 574
no-snapshot | 50 930 795 | 51 141 006
snapshot | 48 072 037 | 48 093 572
pypy
Manifest Size:
limit | none | 1000
------------|-------------|------------
no-sparse | 193 987 784 | 193 987 784
no-snapshot | 163 171 745 | 163 312 229
snapshot | 34 605 900 | 34 600 750
Manifest Chain length data
limit || none || 1000 ||
value || average | max || average | max ||
------------||---------|---------||---------|---------||
no-sparse || 101 | 692 || 101 | 692 ||
no-snapshot || 151 | 1307 || 148 | 1000 ||
snapshot || 128 | 1309 || 125 | 1000 ||
Full Store Size
limit | none | 1000
------------|-------------|------------
no-sparse | 495 931 473 | 495 931 473
no-snapshot | 465 441 017 | 465 581 501
snapshot | 355 467 301 | 355 472 451
Mozilla
Manifest Size:
limit | none | 1000
------------|----------------|---------------
no-sparse | 416 757 148 | 1 869 009 668
no-snapshot | 401 592 370 | 1 843 493 795
snapshot | 224 359 521 | 284 615 500
Manifest Chain length data
limit || none || 1000 ||
value || average | max || average | max ||
------------||---------|---------||---------|---------||
no-sparse || 15 333 | 58 980 || 468 | 1 000 ||
no-snapshot || 15 336 | 58 980 || 469 | 1 000 ||
snapshot || 15 338 | 58 983 || 469 | 1 000 ||
Full Store Size
limit | none | 1000
------------|----------------|---------------
no-sparse | 2 712 477 887 | 4 164 995 451
no-snapshot | 2 698 887 835 | 4 141 054 304
snapshot | 2 518 130 385 | 2 578 587 596
Netbeans
Manifest Size:
limit | none | 1000
------------|----------------|---------------
no-sparse | 4 766 794 101 | 4 870 642 687
no-snapshot | 4 334 806 082 | 4 428 681 309
snapshot | 232 659 666 | 240 330 665
Manifest Chain length data
limit || none || 1000 ||
value || average | max || average | max ||
------------||---------|---------||---------|---------||
no-sparse || 597 | 6802 || 254 | 1 000 ||
no-snapshot || 648 | 6 802 || 305 | 1 000 ||
snapshot || 613 | 6 804 || 282 | 1 000 ||
Full Store Size
limit | none | 1000
------------|----------------|---------------
no-sparse | 5 807 347 998 | 5 911 196 584
no-snapshot | 5 375 398 602 | 5 469 273 829
snapshot | 1 282 519 928 | 1 290 190 927
Private repo #1
Manifest Size:
limit | none | 1000
------------|-----------------|---------------
no-sparse | 41 389 010 840 | 41 398 162 091
no-snapshot | 9 737 319 435 | 10 223 773 150
snapshot | 744 215 807 | 747 961 822
Manifest Chain length data
limit || none || 1000 ||
value || average | max || average | max ||
------------||---------|---------||---------|---------||
no-sparse || 245 | 8 885 || 81 | 1 000 ||
no-snapshot || 1 225 | 8 885 || 336 | 1 000 ||
snapshot || 1 068 | 7 909 || 307 | 1 000 ||
Full Store Size
limit | none | 1000
------------|----------------|---------------
no-sparse | 49 646 065 126 | 49 655 216 377
no-snapshot | 17 924 862 856 | 18 411 316 571
snapshot | 9 009 024 710 | 9 012 770 725
Private repo #2
We currently have less data available for that repository.
* Before is a sparse-revlog repository without this series
* After is a sparse-revlog repository with this series + 1000 chain limit
Manifest Size:
Before: 1 531 485 040 bytes
After: 1 091 422 451 bytes
Manifest Chain:
Before: 2 218 avg; 6 575 Max
After: 442 avg; 1 000 Max
Full Store Size
Before: 15 203 955 615
after: 8 207 180 693
author | Boris Feld <boris.feld@octobus.net> |
---|---|
date | Fri, 07 Sep 2018 11:18:45 -0400 |
parents | e266e75d77dc |
children | d6d094259d9c |
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# This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, see # <http://www.gnu.org/licenses/>. # This file is part of urlgrabber, a high-level cross-protocol url-grabber # Copyright 2002-2004 Michael D. Stenner, Ryan Tomayko # Modified by Benoit Boissinot: # - fix for digest auth (inspired from urllib2.py @ Python v2.4) # Modified by Dirkjan Ochtman: # - import md5 function from a local util module # Modified by Augie Fackler: # - add safesend method and use it to prevent broken pipe errors # on large POST requests """An HTTP handler for urllib2 that supports HTTP 1.1 and keepalive. >>> import urllib2 >>> from keepalive import HTTPHandler >>> keepalive_handler = HTTPHandler() >>> opener = urlreq.buildopener(keepalive_handler) >>> urlreq.installopener(opener) >>> >>> fo = urlreq.urlopen('http://www.python.org') If a connection to a given host is requested, and all of the existing connections are still in use, another connection will be opened. If the handler tries to use an existing connection but it fails in some way, it will be closed and removed from the pool. To remove the handler, simply re-run build_opener with no arguments, and install that opener. You can explicitly close connections by using the close_connection() method of the returned file-like object (described below) or you can use the handler methods: close_connection(host) close_all() open_connections() NOTE: using the close_connection and close_all methods of the handler should be done with care when using multiple threads. * there is nothing that prevents another thread from creating new connections immediately after connections are closed * no checks are done to prevent in-use connections from being closed >>> keepalive_handler.close_all() EXTRA ATTRIBUTES AND METHODS Upon a status of 200, the object returned has a few additional attributes and methods, which should not be used if you want to remain consistent with the normal urllib2-returned objects: close_connection() - close the connection to the host readlines() - you know, readlines() status - the return status (i.e. 404) reason - english translation of status (i.e. 'File not found') If you want the best of both worlds, use this inside an AttributeError-catching try: >>> try: status = fo.status >>> except AttributeError: status = None Unfortunately, these are ONLY there if status == 200, so it's not easy to distinguish between non-200 responses. The reason is that urllib2 tries to do clever things with error codes 301, 302, 401, and 407, and it wraps the object upon return. """ # $Id: keepalive.py,v 1.14 2006/04/04 21:00:32 mstenner Exp $ from __future__ import absolute_import, print_function import errno import hashlib import socket import sys import threading from .i18n import _ from . import ( node, pycompat, urllibcompat, util, ) from .utils import ( procutil, ) httplib = util.httplib urlerr = util.urlerr urlreq = util.urlreq DEBUG = None class ConnectionManager(object): """ The connection manager must be able to: * keep track of all existing """ def __init__(self): self._lock = threading.Lock() self._hostmap = {} # map hosts to a list of connections self._connmap = {} # map connections to host self._readymap = {} # map connection to ready state def add(self, host, connection, ready): self._lock.acquire() try: if host not in self._hostmap: self._hostmap[host] = [] self._hostmap[host].append(connection) self._connmap[connection] = host self._readymap[connection] = ready finally: self._lock.release() def remove(self, connection): self._lock.acquire() try: try: host = self._connmap[connection] except KeyError: pass else: del self._connmap[connection] del self._readymap[connection] self._hostmap[host].remove(connection) if not self._hostmap[host]: del self._hostmap[host] finally: self._lock.release() def set_ready(self, connection, ready): try: self._readymap[connection] = ready except KeyError: pass def get_ready_conn(self, host): conn = None self._lock.acquire() try: if host in self._hostmap: for c in self._hostmap[host]: if self._readymap[c]: self._readymap[c] = 0 conn = c break finally: self._lock.release() return conn def get_all(self, host=None): if host: return list(self._hostmap.get(host, [])) else: return dict(self._hostmap) class KeepAliveHandler(object): def __init__(self): self._cm = ConnectionManager() #### Connection Management def open_connections(self): """return a list of connected hosts and the number of connections to each. [('foo.com:80', 2), ('bar.org', 1)]""" return [(host, len(li)) for (host, li) in self._cm.get_all().items()] def close_connection(self, host): """close connection(s) to <host> host is the host:port spec, as in 'www.cnn.com:8080' as passed in. no error occurs if there is no connection to that host.""" for h in self._cm.get_all(host): self._cm.remove(h) h.close() def close_all(self): """close all open connections""" for host, conns in self._cm.get_all().iteritems(): for h in conns: self._cm.remove(h) h.close() def _request_closed(self, request, host, connection): """tells us that this request is now closed and that the connection is ready for another request""" self._cm.set_ready(connection, 1) def _remove_connection(self, host, connection, close=0): if close: connection.close() self._cm.remove(connection) #### Transaction Execution def http_open(self, req): return self.do_open(HTTPConnection, req) def do_open(self, http_class, req): host = urllibcompat.gethost(req) if not host: raise urlerr.urlerror('no host given') try: h = self._cm.get_ready_conn(host) while h: r = self._reuse_connection(h, req, host) # if this response is non-None, then it worked and we're # done. Break out, skipping the else block. if r: break # connection is bad - possibly closed by server # discard it and ask for the next free connection h.close() self._cm.remove(h) h = self._cm.get_ready_conn(host) else: # no (working) free connections were found. Create a new one. h = http_class(host) if DEBUG: DEBUG.info("creating new connection to %s (%d)", host, id(h)) self._cm.add(host, h, 0) self._start_transaction(h, req) r = h.getresponse() # The string form of BadStatusLine is the status line. Add some context # to make the error message slightly more useful. except httplib.BadStatusLine as err: raise urlerr.urlerror( _('bad HTTP status line: %s') % pycompat.sysbytes(err.line)) except (socket.error, httplib.HTTPException) as err: raise urlerr.urlerror(err) # if not a persistent connection, don't try to reuse it if r.will_close: self._cm.remove(h) if DEBUG: DEBUG.info("STATUS: %s, %s", r.status, r.reason) r._handler = self r._host = host r._url = req.get_full_url() r._connection = h r.code = r.status r.headers = r.msg r.msg = r.reason return r def _reuse_connection(self, h, req, host): """start the transaction with a re-used connection return a response object (r) upon success or None on failure. This DOES not close or remove bad connections in cases where it returns. However, if an unexpected exception occurs, it will close and remove the connection before re-raising. """ try: self._start_transaction(h, req) r = h.getresponse() # note: just because we got something back doesn't mean it # worked. We'll check the version below, too. except (socket.error, httplib.HTTPException): r = None except: # re-raises # adding this block just in case we've missed # something we will still raise the exception, but # lets try and close the connection and remove it # first. We previously got into a nasty loop # where an exception was uncaught, and so the # connection stayed open. On the next try, the # same exception was raised, etc. The trade-off is # that it's now possible this call will raise # a DIFFERENT exception if DEBUG: DEBUG.error("unexpected exception - closing " "connection to %s (%d)", host, id(h)) self._cm.remove(h) h.close() raise if r is None or r.version == 9: # httplib falls back to assuming HTTP 0.9 if it gets a # bad header back. This is most likely to happen if # the socket has been closed by the server since we # last used the connection. if DEBUG: DEBUG.info("failed to re-use connection to %s (%d)", host, id(h)) r = None else: if DEBUG: DEBUG.info("re-using connection to %s (%d)", host, id(h)) return r def _start_transaction(self, h, req): # What follows mostly reimplements HTTPConnection.request() # except it adds self.parent.addheaders in the mix and sends headers # in a deterministic order (to make testing easier). headers = util.sortdict(self.parent.addheaders) headers.update(sorted(req.headers.items())) headers.update(sorted(req.unredirected_hdrs.items())) headers = util.sortdict((n.lower(), v) for n, v in headers.items()) skipheaders = {} for n in (r'host', r'accept-encoding'): if n in headers: skipheaders[r'skip_' + n.replace(r'-', r'_')] = 1 try: if urllibcompat.hasdata(req): data = urllibcompat.getdata(req) h.putrequest( req.get_method(), urllibcompat.getselector(req), **skipheaders) if r'content-type' not in headers: h.putheader(r'Content-type', r'application/x-www-form-urlencoded') if r'content-length' not in headers: h.putheader(r'Content-length', r'%d' % len(data)) else: h.putrequest( req.get_method(), urllibcompat.getselector(req), **skipheaders) except socket.error as err: raise urlerr.urlerror(err) for k, v in headers.items(): h.putheader(k, v) h.endheaders() if urllibcompat.hasdata(req): h.send(data) class HTTPHandler(KeepAliveHandler, urlreq.httphandler): pass class HTTPResponse(httplib.HTTPResponse): # we need to subclass HTTPResponse in order to # 1) add readline(), readlines(), and readinto() methods # 2) add close_connection() methods # 3) add info() and geturl() methods # in order to add readline(), read must be modified to deal with a # buffer. example: readline must read a buffer and then spit back # one line at a time. The only real alternative is to read one # BYTE at a time (ick). Once something has been read, it can't be # put back (ok, maybe it can, but that's even uglier than this), # so if you THEN do a normal read, you must first take stuff from # the buffer. # the read method wraps the original to accommodate buffering, # although read() never adds to the buffer. # Both readline and readlines have been stolen with almost no # modification from socket.py def __init__(self, sock, debuglevel=0, strict=0, method=None): extrakw = {} if not pycompat.ispy3: extrakw[r'strict'] = True extrakw[r'buffering'] = True httplib.HTTPResponse.__init__(self, sock, debuglevel=debuglevel, method=method, **extrakw) self.fileno = sock.fileno self.code = None self._rbuf = '' self._rbufsize = 8096 self._handler = None # inserted by the handler later self._host = None # (same) self._url = None # (same) self._connection = None # (same) _raw_read = httplib.HTTPResponse.read _raw_readinto = getattr(httplib.HTTPResponse, 'readinto', None) def close(self): if self.fp: self.fp.close() self.fp = None if self._handler: self._handler._request_closed(self, self._host, self._connection) def close_connection(self): self._handler._remove_connection(self._host, self._connection, close=1) self.close() def info(self): return self.headers def geturl(self): return self._url def read(self, amt=None): # the _rbuf test is only in this first if for speed. It's not # logically necessary if self._rbuf and amt is not None: L = len(self._rbuf) if amt > L: amt -= L else: s = self._rbuf[:amt] self._rbuf = self._rbuf[amt:] return s s = self._rbuf + self._raw_read(amt) self._rbuf = '' return s # stolen from Python SVN #68532 to fix issue1088 def _read_chunked(self, amt): chunk_left = self.chunk_left parts = [] while True: if chunk_left is None: line = self.fp.readline() i = line.find(';') if i >= 0: line = line[:i] # strip chunk-extensions try: chunk_left = int(line, 16) except ValueError: # close the connection as protocol synchronization is # probably lost self.close() raise httplib.IncompleteRead(''.join(parts)) if chunk_left == 0: break if amt is None: parts.append(self._safe_read(chunk_left)) elif amt < chunk_left: parts.append(self._safe_read(amt)) self.chunk_left = chunk_left - amt return ''.join(parts) elif amt == chunk_left: parts.append(self._safe_read(amt)) self._safe_read(2) # toss the CRLF at the end of the chunk self.chunk_left = None return ''.join(parts) else: parts.append(self._safe_read(chunk_left)) amt -= chunk_left # we read the whole chunk, get another self._safe_read(2) # toss the CRLF at the end of the chunk chunk_left = None # read and discard trailer up to the CRLF terminator ### note: we shouldn't have any trailers! while True: line = self.fp.readline() if not line: # a vanishingly small number of sites EOF without # sending the trailer break if line == '\r\n': break # we read everything; close the "file" self.close() return ''.join(parts) def readline(self): # Fast path for a line is already available in read buffer. i = self._rbuf.find('\n') if i >= 0: i += 1 line = self._rbuf[:i] self._rbuf = self._rbuf[i:] return line # No newline in local buffer. Read until we find one. chunks = [self._rbuf] i = -1 readsize = self._rbufsize while True: new = self._raw_read(readsize) if not new: break chunks.append(new) i = new.find('\n') if i >= 0: break # We either have exhausted the stream or have a newline in chunks[-1]. # EOF if i == -1: self._rbuf = '' return ''.join(chunks) i += 1 self._rbuf = chunks[-1][i:] chunks[-1] = chunks[-1][:i] return ''.join(chunks) def readlines(self, sizehint=0): total = 0 list = [] while True: line = self.readline() if not line: break list.append(line) total += len(line) if sizehint and total >= sizehint: break return list def readinto(self, dest): if self._raw_readinto is None: res = self.read(len(dest)) if not res: return 0 dest[0:len(res)] = res return len(res) total = len(dest) have = len(self._rbuf) if have >= total: dest[0:total] = self._rbuf[:total] self._rbuf = self._rbuf[total:] return total mv = memoryview(dest) got = self._raw_readinto(mv[have:total]) dest[0:have] = self._rbuf got += len(self._rbuf) self._rbuf = '' return got def safesend(self, str): """Send `str' to the server. Shamelessly ripped off from httplib to patch a bad behavior. """ # _broken_pipe_resp is an attribute we set in this function # if the socket is closed while we're sending data but # the server sent us a response before hanging up. # In that case, we want to pretend to send the rest of the # outgoing data, and then let the user use getresponse() # (which we wrap) to get this last response before # opening a new socket. if getattr(self, '_broken_pipe_resp', None) is not None: return if self.sock is None: if self.auto_open: self.connect() else: raise httplib.NotConnected # send the data to the server. if we get a broken pipe, then close # the socket. we want to reconnect when somebody tries to send again. # # NOTE: we DO propagate the error, though, because we cannot simply # ignore the error... the caller will know if they can retry. if self.debuglevel > 0: print("send:", repr(str)) try: blocksize = 8192 read = getattr(str, 'read', None) if read is not None: if self.debuglevel > 0: print("sending a read()able") data = read(blocksize) while data: self.sock.sendall(data) data = read(blocksize) else: self.sock.sendall(str) except socket.error as v: reraise = True if v[0] == errno.EPIPE: # Broken pipe if self._HTTPConnection__state == httplib._CS_REQ_SENT: self._broken_pipe_resp = None self._broken_pipe_resp = self.getresponse() reraise = False self.close() if reraise: raise def wrapgetresponse(cls): """Wraps getresponse in cls with a broken-pipe sane version. """ def safegetresponse(self): # In safesend() we might set the _broken_pipe_resp # attribute, in which case the socket has already # been closed and we just need to give them the response # back. Otherwise, we use the normal response path. r = getattr(self, '_broken_pipe_resp', None) if r is not None: return r return cls.getresponse(self) safegetresponse.__doc__ = cls.getresponse.__doc__ return safegetresponse class HTTPConnection(httplib.HTTPConnection): # use the modified response class response_class = HTTPResponse send = safesend getresponse = wrapgetresponse(httplib.HTTPConnection) ######################################################################### ##### TEST FUNCTIONS ######################################################################### def continuity(url): md5 = hashlib.md5 format = '%25s: %s' # first fetch the file with the normal http handler opener = urlreq.buildopener() urlreq.installopener(opener) fo = urlreq.urlopen(url) foo = fo.read() fo.close() m = md5(foo) print(format % ('normal urllib', node.hex(m.digest()))) # now install the keepalive handler and try again opener = urlreq.buildopener(HTTPHandler()) urlreq.installopener(opener) fo = urlreq.urlopen(url) foo = fo.read() fo.close() m = md5(foo) print(format % ('keepalive read', node.hex(m.digest()))) fo = urlreq.urlopen(url) foo = '' while True: f = fo.readline() if f: foo = foo + f else: break fo.close() m = md5(foo) print(format % ('keepalive readline', node.hex(m.digest()))) def comp(N, url): print(' making %i connections to:\n %s' % (N, url)) procutil.stdout.write(' first using the normal urllib handlers') # first use normal opener opener = urlreq.buildopener() urlreq.installopener(opener) t1 = fetch(N, url) print(' TIME: %.3f s' % t1) procutil.stdout.write(' now using the keepalive handler ') # now install the keepalive handler and try again opener = urlreq.buildopener(HTTPHandler()) urlreq.installopener(opener) t2 = fetch(N, url) print(' TIME: %.3f s' % t2) print(' improvement factor: %.2f' % (t1 / t2)) def fetch(N, url, delay=0): import time lens = [] starttime = time.time() for i in range(N): if delay and i > 0: time.sleep(delay) fo = urlreq.urlopen(url) foo = fo.read() fo.close() lens.append(len(foo)) diff = time.time() - starttime j = 0 for i in lens[1:]: j = j + 1 if not i == lens[0]: print("WARNING: inconsistent length on read %i: %i" % (j, i)) return diff def test_timeout(url): global DEBUG dbbackup = DEBUG class FakeLogger(object): def debug(self, msg, *args): print(msg % args) info = warning = error = debug DEBUG = FakeLogger() print(" fetching the file to establish a connection") fo = urlreq.urlopen(url) data1 = fo.read() fo.close() i = 20 print(" waiting %i seconds for the server to close the connection" % i) while i > 0: procutil.stdout.write('\r %2i' % i) procutil.stdout.flush() time.sleep(1) i -= 1 procutil.stderr.write('\r') print(" fetching the file a second time") fo = urlreq.urlopen(url) data2 = fo.read() fo.close() if data1 == data2: print(' data are identical') else: print(' ERROR: DATA DIFFER') DEBUG = dbbackup def test(url, N=10): print("performing continuity test (making sure stuff isn't corrupted)") continuity(url) print('') print("performing speed comparison") comp(N, url) print('') print("performing dropped-connection check") test_timeout(url) if __name__ == '__main__': import time try: N = int(sys.argv[1]) url = sys.argv[2] except (IndexError, ValueError): print("%s <integer> <url>" % sys.argv[0]) else: test(url, N)