If I read your code correctly, you're forking a new process for each row, then in that process you start another process (the `./alert_main.pl line) that presumably does something with that row.

That strikes me as very inefficient. You'll probably get much better efficiency if you set up each sub-process to handle a more significant chunk of data (for instance, process 20% of the total number of rows). Fork() and exec() are pretty fast on most UNIX systems, but not THAT fast. Also, inlining alert_main.pl will probably make the system a LOT more efficient.

Also, unless ./alert_main.pl actually does something with the database this is never going to improve the performance, if the bottleneck is in waiting for the rows to arrive.