Why do you want to use MySQL ? I would like to see PostgreSQL support or even databse independant way.
This is the developers mailing list, not sa-talk. If after looking at the code you think it could and should be more RDBMS independent than it is, file a bug report in Bugzilla, preferably with a patch.
If you want to express your preference of RDBMS as a user (installer) of SpamAssassin, discuss it on sa-talk.
In the meantime, in this thread, I'm discussing scalability and performance issues for the Bayes database in general. MySQL happens to be what I'm working with and provides a test case. I'm sure that if it scales to tens or hundreds of thousands of user accounts with MySQL then it will for PostgreSQL or Oracle too.
-- sidney
