Faster Regexes: What to do when text matching is your bottleneck

By Aaron Crane (‎arc‎) from,
Date: Friday, 16 November 2007 17:15
Duration: 20 minutes
Target audience: Intermediate
Language: English
Tags: optimisation regex

We all know how good Perl is at munging text. But what do you do when your Perl text-munging code isn't fast enough for what you're trying to do?

We needed to extract useful information from tens of gigabytes of web-server log files. Our Perl code was simple and obvious, but not fast enough for our purposes. When profiling revealed a frequently-executed regex as the bottleneck, we tried several things to make it faster.

This talk looks at what we did to speed up our regex-heavy code (by a factor of well over 100 in some places), identifying a few general-purpose optimisation techniques on the way.