Bugs item #1607951, was opened at 2006-12-03 12:28 Message generated for change (Comment added) made by akuchling You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1607951&group_id=5470
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Python Library Group: Python 2.5 Status: Open Resolution: None Priority: 5 Private: No Submitted By: Matthias Klose (doko) Assigned to: A.M. Kuchling (akuchling) Summary: mailbox.Maildir re-reads directory too often Initial Comment: [forwarded from http://bugs.debian.org/401395] Various functions in mailbox.Maildir call self._refresh, which always re-reads the cur and new directories with os.listdir. _refresh should stat each of the two directories first to see if they changed. This cuts processing time of a series of lookups down by a factor of the number of messages in the folder, a potentially large number. ---------------------------------------------------------------------- >Comment By: A.M. Kuchling (akuchling) Date: 2006-12-14 14:09 Message: Logged In: YES user_id=11375 Originator: NO Stray thought: would it help if the patch stored the (mtime - 1sec) instead of the mtime? Successive calls in the same second would then always re-read the directories, but once the clock ticks to the next second, re-reads would only occur if the directories have actually changed. The check would be 'if new_mtime > self._new_mtime' instead of '=='. Is this sort of mtime-based checking reliable on remote filesystems such as NFS? ---------------------------------------------------------------------- Comment By: A.M. Kuchling (akuchling) Date: 2006-12-13 08:38 Message: Logged In: YES user_id=11375 Originator: NO By stat()'ing the directories, do you mean checking the mtime? I think this isn't safe because of the limited resolution of mtime on filesystems; ext3 seems to have a 1-second resolution for mtime, for example. This means that _refresh() might read a directory, and if some other process adds or deletes a message in the same second, _refresh() couldn't detect the change. Is there some other property of directories that could be used for a more reliable check? The attached patch implements checking of mtime, but I don't recommend applying it; it causes the test suite in test_mailbox.py to break all over the place, because the process modifies mailboxes so quickly that the mtime check doesn't notice the process's own changes. I'll wait a bit for any alternative suggestion, and then close this bug as "won't fix". File Added: mailbox-mtime.patch ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1607951&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
