I believe that this line is what's slowing you down.

You are wrong to believe that. I suggested this nearly a month ago, and the OP tested it and verified that avoiding the concatenation did not make a difference.

Since then, the OP advised us that they had raised it as a perl issue on github; it has been investigated there, and tonyc++ just reported back to us on progress made towards fixing the problem.

In reply to Re^2: RE on lines read from in-memory scalar is very slow by hv
in thread RE on lines read from in-memory scalar is very slow by Danny

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