I'm working on optimizing Squirrelmail performance. Their web site suggested enabling "server-side sorting" and "server-side threading".
UW imapd supports full server-side sorting and threading. As there is is no way to disable it, it does not require enabling.
1) I see that SORT is listed as a CAPABILITY--is this all that I need to be concerned with
Yes
or are there "tweaks" to make it more efficient?
No
2) There are multiple THREAD CAPABILITY entries above. Are there more potential THREAD features that can be added?
Yes; but at the current time there are only two defined threading algorithms: ORDEREDSUBJECT and REFERENCES. REFERENCES is the algorithm that most people consider to be "threading".
3) Is there a way to tell if the IMAP clients are actually using the CAPABILITYs?
If the client issues SORT and THREAD commands, then it is using the capability. You can determine this by watching the protocol transactions.
Use of server-side sorting and threading depends upon two things: 1) Server support: this is announced by the CAPABILITY 2) Client support: typically this noted in the client documentation.
That is, how can I test to ensure the "CAPABILITY" is working properly?
Sorting and threading works correctly in UW imapd and in Cyrus imapd.
I do not recommend attempting to use sorting and threading in Courier, as that server is not an IMAP server and the sorting/threading features that it advertises are known to be broken.
-- Mark --
http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.
