If I'm not mistaken, the line you quoted from the docs means Tie::File reads the rest of the file and writes it back out every time you do a splice.

5MB isn't particularly big. Since you end up reading the entire file anyway, you might be better off loading the entire file into an array, making changes to the array, then dumping the array back out if changes were made.

Update: Here's something to get you started 

my @file;
my $changed;
{
   open(my $fh, '<', $fn)
      or die("Unable to open file \"$fn\": $!\n");

   while (<$fh>) {
      if (...[ need to delete this line ]...) {
         $changed = 1;
      } else {
         push @file, $_;
      }
      if (...[ need to insert a line after this line ]...) {
         push @file, ...;
         $changed = 1;
      }
   }
}

if ($changed) {
   open(my $fh, '>', $fn)
      or die("Unable to open file \"$fn\": $!\n");

   print $fh @file;
}

[download]

In reply to Re: Tie::File performance issue by ikegami
in thread Tie::File performance issue by A200560

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