Mysql – storing a mirror of IMAP/pop3 folder/inbox in a local DB, what choices are there

MySQLpostgresql

I have a email inbox that will soon hit 4 million messages, I have an app that runs different policies over the inbox to associate emails with each other much like the conversation plugin for Thunderbird.
It is now becoming impossible to do so and I have been thinking about moving the emails to a DB as they come in and process them there and then, the processor needs to access the body and header. What database engine is best for this task mysql,postgre,etc?

Best Answer

You could try DBMail as local IMAP storage, and either use any of various IMAP syncing solutions or regular SMTP forwarding to get the mail in there.