If you want a really fast search, look at Sean O’Rourke’s Perl code which won the widefinder parallel search performance contest.

But as you are into monitoring, check out the brazillion scripts which do that. Nagios' check_logfiles may be a bit basic, but then there are swatch, logwatch or SEC if you want to do really fancy correlation on your logs. Plus there should be Oracle specific scanners, Nagios plug-ins, whatnot...

If your primary mission is not to learn Perl, then there is no need to write lowly grep loops...