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Re: very slow processing

by philipbailey (Deacon)
on Aug 20, 2014 at 19:23 UTC ( #1098148=note: print w/replies, xml ) Need Help??

in reply to very slow processing

My eye is drawn to this:

    $line =~ /\[(.+?)\] .* \[(.+?)\] .* \[[^]]+\] \s+ (.*) /x or next ;

It seems to me that the repeated .* is likely to result in a lot of backtracking during the match of the regex. I suggest you try replacing the first two .* expressions with something like [^\[]+ and add a $ anchor at the end. That would change that line to:

    $line =~ /\[(.+?)\] [^\[]+ \[(.+?)\] [^\[]+ \[[^]]+\] \s+ (.*)$ /x or next ;

There may be something more elegant you could do (and somebody will chip in) but I bet that will result in a speed improvement.

Mind you, the O n^2 algorithm won't help.

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