Dovecot mailbox list index cache invalidation on mailbox create, rename, or delete

Dovecot mailbox list index cache invalidation on mailbox create, rename, or delete

The goal is to keep IMAP LIST responses consistent immediately after a mailbox is created, renamed, or removed, without waiting for the mailbox list index TTL to expire or reloading the server.

Dovecot accelerates mailbox listings using a cached index. The cache lifetime appears to be governed by time-based expiration or manual refresh, but it is not clear whether Dovecot automatically invalidates affected entries when mailbox directories change. This uncertainty matters for shared mailboxes and dynamic namespace deployments where clients expect near-real-time visibility.

The configuration must avoid disabling the cache entirely, since LIST performance on large installations depends on it. Any invalidation mechanism should apply only to changed mailboxes rather than flushing the whole index.

Can mailbox list index entries be invalidated automatically when a mailbox is created, renamed, or deleted? Which Dovecot setting controls the refresh trigger for mailbox lifecycle events? Is a full service reload required for new mailboxes to appear in IMAP LIST output?