This isn't really a bug, but I think it isn't the best approach to keep a separate count of the number of rows in the mail_queue table in the systemvars cache.

Seems to me that there is a potential for the count in the cache to not reflect the actual count in the table (resulting in mail in the queue not being serviced in a timely manner).

Why go to all this trouble?

Doing "select count(*) as count from ibf_mail_queue" is a query that is about as fast as you can get. MySQL doesn't even have to scan the table to count the rows as this count is maintained in the system tables for the database.

Anyway, it is a small thing, but I think you should remove using this extra variable and just query the count directly.

Seems simpler to me. Maybe I'm missing something about why this was done in the first place?

i think the new mail_queue feature is not finished

http://www.invisionboard.com/?ipb21roadmap

Ability to "hold" an item in the mail queue for later processing <-- in black

This is not a bug in IPB but is more of a feature suggestion.