On 29 Jun 2017, at 18.44, van der Kamp, John jkamp@amazon.nl wrote:

Hi,

I was testing around with 2.2.31, and saw that it made new extra connections to the backend imap server whenever you make a new mailbox. So client does:

A001 login username password A002 create subfolder

Previously, dovecot would just send the create command to the backend, but now does (including connection IDs):

[conn1] 9 CREATE "subfolder" [conn1] 10 EXAMINE "INBOX" [conn2] 12 LOGIN "username" "password" [conn2] 11 SELECT "subfolder"

The new EXAMINE Command is a bit weird, but the secondary connection is a complete waste. I also haven't seen any other action on it yet, but it's kept around. If you make more mailboxes, every time you gain an extra connection from dovecot to the backend imap server. And they all stick around. I don't know which changes this behavior triggered, there were loads of imapc fixes the last couple of releases.

It's caused by https://github.com/dovecot/core/commit/444e2d726b0c351e28888b10a9593426ad5c4... https://github.com/dovecot/core/commit/444e2d726b0c351e28888b10a9593426ad5c4... - completely different from what I guessed..