I am looking for tips on improving IMAP search performance using Courier IMAP. The current version is 4.2.1. Unlike in the question "Fast search for IMAP?", I'm specifically looking for server side improvements.
Access performance is already quite good on fairly large accounts, but search is slow. Is there some kind of tool / add-on that can be used to generate good indices for the various interesting mail fields?
Best Answer
Looking through the courier imapd docs and my installs of it it doesn't seem to have a cache or index of anything beyond the uids of the messages.
Have you looked at dovecot? It looks like you can migrate to it without users noticing. It also has a discussion of how it cache's various bits of information in message database.
All that being said, a reading of the discussion of caching and indexing the message folder leads me to believe that perhaps the real place for caching and indexing the messages is on the client not the server. Probably a head-to-head test would be in order.