You might want to start transitioning towards database type solutions as a 'hint' that the MotherLog should become the MotherDB.

I'd suggest looking at the DBI module and one of the following:

• DBD::CSV - treat a text file like a SQL database
• DBD::ODBC - driver for ODBC connections (i.e. Access, MS SQL Server, etc)

I've used DBD::ODBC to connect to MS SQL Server and it worked great.

Having several programs access this monster log file is going to be painful. It won't get better -- trust me on this. Start agitating on getting this done right. You'll save a few sanity points if you can get the 'powers that be' to start changing their infrastructure.