[Dovecot] Storing Dovecot index files on sql

[Timo Sirainen]

On Thu, 2011-01-27 at 12:49 -0600, list at airstreamcomm.net wrote:
> Our question to the community is whether sql storage for index
> files has ever been considered, what issues would this introduce, and
> if it's even feasible? 

Its performance would be horrible.

Only dovecot.index.cache file's contents would in theory benefit in
being stored in a bit more complex database, but the database would have
to have very low latency. Maybe Berkeley DB would work ok. Any SQL
database would have too high latency. dovecot.index and
dovecot.index.log files' contents are something that don't really fit
into database at all.

I'll still probably implement support for SQL databases at some point,
but I'm not expecting the performance to be anything close to mailbox
formats on filesystem.