Why is my regex so much slower compiled than interpreted ?
- by miket2e
I have a large and complex C# regex that runs OK when interpreted, but is a bit slow. I'm trying to speed this up by setting RegexOptions.Compiled, and this seems to take about 30 seconds for the first time and instantly after that. I'm trying to negate this by compiling the regex to an assembly first, so my app can be as fast as possible.
My problem is when the compiling delay takes place:
Regex myComplexRegex = new Regex(regexText, RegexOptions.Compiled);
MatchCollection matches = myComplexRegex.Matches(searchText);
foreach (Match match in matches) // <--- when the one-time long delay kicks in
{
}
This is making compiling to an assembly basically useless, as I still get the delay on the first foreach call. What I want is for all the compiling delay to be done in advance when I compile to the assembly, not when the user runs the app. Where am I going wrong ?
(The code I'm using to compile to an assembly is similar to http://www.dijksterhuis.org/regular-expressions-advanced/ , if that's relevant ).
