Most of the regex strings are constant, a few hundred may contain simple constructs like alternation and character classes: (f?oo|bar|baz|etc)[\w\-]*\.[0-9]{3,}) We only extract the data if it matches. As many have suggested I benchmarked a typical case with the actual data and unless something is wrong the difference is extreme: 
my %cases = (
  'one_large'  => sub { if($text=~/(stuff?)m0r3(?:[^:]*\.)?($big_strin
+g)/i){my $match="$1:$2"}},
  'many_small' => sub { for(@strings){ if($text=~/(stuff?)m0r3(?:[^:]*
+\.)?($_)/i){my $match="$1:$2"}}},
);

print 
'$text       = ', length $text,       " characters\n",
'$big_string = ', length $big_string, " characters\n", 
'@strings    = ', scalar @strings,    " items\n\n";

cmpthese( 0, \%cases);

[download]
Results: 
$text       = 4578 characters
$big_string = 210724 characters
@strings    = 10634 items

             Rate many_small  one_large
many_small 1.05/s         --      -100%
one_large   630/s     60089%         --
   --

[download]

In reply to Re^2: pattern matching with large regex by Anonymous Monk
in thread pattern matching with large regex by Anonymous Monk

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