[Tickets #6972] mailbox listing speed-up

[bugs at horde.org]

DO NOT REPLY TO THIS MESSAGE. THIS EMAIL ADDRESS IS NOT MONITORED.

Ticket URL: http://bugs.horde.org/ticket/6972
------------------------------------------------------------------------------
  Ticket             | 6972
  Created By         | ziba at umich.edu
  Summary            | mailbox listing speed-up
  Queue              | IMP
  Version            | 4.2
  Type               | Enhancement
  State              | New
  Priority           | 2. Medium
  Milestone          |
  Patch              | 1
  Owners             |
+New Attachment     | Tree.php.diff
------------------------------------------------------------------------------


ziba at umich.edu (2008-06-24 15:49) wrote:

After our recent horde/imp upgrade at umich, we've seen login times rise
from ~5-10 seconds to ~10-30 seconds.   The bulk of this time is spent
building the mailbox list in IMP_Tree (imp/lib/IMAP/Tree.php).  We've
made some changes which dramatically reduce the IMP_Tree startup time
and would love some feedback and basic sanity checking before we move
forward with them.

On an unloaded test server in our environment, imap_getmailboxes and
imap_list commands can take up to 1.7 seconds each against our Cyrus system.

First, IMP_Tree calls imap_getmailboxes for each namespace with a %
appended to get one level deep of subfolders.

Second, IMP_Tree::_initSubscribed executes imap_list for each namespace
with an * appended to get all sublevels of folders.

Last, it recursively crawls each folder found during the first set of
imap_getmailboxes and calls imap_getmailboxes on each folder with %
again until all branches have been plumbed.

Our improvements are premised on the fact that one level searches (%)
and searches which return full trees of results (*) actually take the
same time to return from Cyrus.  So we are bypassing all other searches
and starting off with one single full (*) search from the root of the
user's mailbox.

One quirk we had to side step then was that % searches will return
objects for folders which have children that can't be directly accessed
themselves.  The * search will not.

So we just iterate through the php data structure and detect parentless
children and fake up an object for them.  Then, if tree_view is turned
on, we separate non-personal mailboxes into  IMPTREE_OTHER_KEY and
IMPTREE_SHARED_KEY.

Since the list of folders at this point has all the children, we bypass
the recursive calls to expand.