[SM-PLUGINS] Filters under v1.4.1 extremely chatty

[Lee B. <lc...@co...>]

My apologies for the extreme length, but I do want to include what
information I have.

SquirrelMail v1.4.1 caused so many problems here at Cornell when I
upgraded from v1.2.11 that I was forced to downgrade back. The single
biggest issue was that SquirrelMail was crippling our backend IMAP server.
This server is no slouch (Sun VX880 w/8 processors & 32G RAM) so it was
very surprising to everyone here that it did happen.

In an effort to try & figure out what was going on I hacked SquirrelMail
v1.2.11 & v1.4.1 to write out every IMAP command it issued to a file. One
of the biggest issues I saw was that amount of traffic the Filters plugin
generated.

When I captured the traffic generated on a simple message list refresh
without filters from v1.4.1 I saw the following:
LOGIN "time005-demo" <snip very long ticket>
SELECT "INBOX"
EXPUNGE
EXAMINE "INBOX"
EXAMINE "INBOX"
SELECT "INBOX"
EXPUNGE
EXPUNGE
FETCH 1 (FLAGS UID RFC822.SIZE BODY.PEEK[HEADER.FIELDS (Date To Cc From
Subject X-Priority Content-Type)])
LSUB "INBOX." "*"
LIST "" "INBOX.Drafts"
LIST "" "INBOX.Sent"
LIST "" "INBOX.Trash"
LIST "" "INBOX"
LOGOUT


But if I have 3 filters and do the same action I see this:
LOGIN "time005-demo" <snip long ticket>
SELECT "INBOX"
EXPUNGE
EXAMINE "INBOX"
SELECT "INBOX"
EXPUNGE
SEARCH CHARSET US-ASCII ALL From {3}
Lee

LIST "" "INBOX.Drafts"
SEARCH CHARSET US-ASCII ALL From {3}
Dan

LIST "" "INBOX.Drafts"
SEARCH CHARSET US-ASCII ALL From {3}
Jon

LIST "" "INBOX.Drafts"
EXAMINE "INBOX"
SELECT "INBOX"
EXPUNGE
EXPUNGE
FETCH 1 (FLAGS UID RFC822.SIZE BODY.PEEK[HEADER.FIELDS (Date To Cc From
Subject X-Priority Content-Type)])
LSUB "INBOX." "*"
LIST "" "INBOX.Drafts"
LIST "" "INBOX.Sent"
LIST "" "INBOX.Trash"
LIST "" "INBOX"
LOGOUT

It may not look like a lot, but multiply that traffic by hundreds of
simultaneous users all with potentially more than 3 filters (I have 20
myself) and you can see how an IMAP server can be overloaded by requests.

By contrast here's a capture of SquirrelMail 1.2.11 with 3 filters:
LOGIN "time004-demo" <snip login ticket>
SELECT "INBOX"
EXPUNGE
EXAMINE "INBOX"
SELECT "INBOX"
EXPUNGE
LIST "" "INBOX.Drafts"
LIST "" "INBOX.Drafts"
LIST "" "INBOX.Drafts"
EXPUNGE
EXAMINE "INBOX"
EXAMINE "INBOX"
EXPUNGE
SELECT "INBOX"
EXPUNGE
A016 FETCH 1 (FLAGS RFC822.SIZE BODY.PEEK[HEADER.FIELDS (Date To From Cc
Subject X-Priority Content-Type)])

LSUB "INBOX." "*"
LIST "" "INBOX.Drafts"
LIST "" "INBOX.Sent"
LIST "" "INBOX.Trash"
LIST "" "INBOX"
LOGOUT

Not nearly as bad as v1.4.1

While I admit that I'm an atypical user of SquirrelMail (30,000 user base.
Approximately 8,000 active users currently and at times peaking to 300+
simultaneous users) I'm hoping that I can get some help here in trying to
reduce the impact of the plugin short of disabling the feature entirely.

Are there any suggestions on how to reduce the impact filters have by
being so chatty? Maybe exchange or re-write some of the commands issued by
the plugin? I'm not very familiar with IMAP commands, but I am learning
them very quickly.

Thanks for your help.

     Lee Brink
-- 
"I have always wished that my computer would be as easy to use as my
telephone. My wish has come true. I no longer know how to use my
telephone."

-Bjarne Stroustrup, computer science professor, designer of C++
programming language (1950- )