almost every day I have been asked by users to see why they haven't received certain email. Running word search through large text files are getting really tedious.

I tried to import it into a database, but I found it could get to more than a few millions of lines very quickly.

How do you guys use it or how do you WANT to use it?

My own experience with searching for specific addresses/messages has been that grep in linux is more efficient that anything else I've tried.  Migrating logs to a database and search was tedious, even with a custom script to do the bulk insert.  My vote would be for Logsat to include an option to log to a DB table but would not make it a top priority.

I have found a shareware program called 'search and replace'.  It's very fast at finding and listing any specific text in the logs, even multiple instances.  I use a file name mask to search by date range. Database queries are great but this is much faster and very easy.