Using Dovecot 2.3.8 with Postfix & MySQL on Centos.

I have a sql table with account info, email addresses, password, quotas, etc I have another sql table for aliases containing which alias points to what email address. For imap access im using passdb password_query with prefetch.

I setup quotas using count and configured postfix to check quotas with check_policy_service before accepting email.

Discovered that it wont lookup quotas using prefetch. Added a second userdb so quota request can use user_query instead of the imap password_query prefetch version.

 userdb {
     driver = sql
     args = /etc/dovecot/mysql_quota.include
     skip = found
     result_success = return-ok
     result_failure = return-ok
 }

This worked for existing email addresses in the accounts table. But any email sent to an alias was rejected because user not found. Not by postfix, postfix can see its an alias, but when postfix does check_policy_service dovecot issued the rejection because its not finding the alias in the accounts table per the userdb user_query.

I added "result_failure = return-ok" to the userdb so if user_query doesn't find the address postfix is asking to accept mail for, it will fall back on quota default values. Then dovecot isn't forcing the mail to be rejected and postfix knows if its a valid user or alias. This seems to solve the issue, dovecot will return per user quotas or if not found then the global quota and let postfix decided whats a valid address to accept or reject.

But now there is a side effect. Every time you ask dovecot for a quota, and if its a first time use of a newly created account dovecot creates the index directories and index files on disk. Because im using result_failure=return-ok which tells dovecot the user was found to prevent aliases from being rejected, dovecot is also creating directories and indexes for those aliases postfix is sending over check_policy_service.

First question: Is this the best way to configure dovecot using quota verification for postfix to work will aliases?

Second question: How can i prevent directories and indexes being created for non found user (aliases) accounts?

Thank you.