comment on

Nice meditation!

After a bit of review I realized that the problem was due to the way I was implementing the cache lookup. The process was essentially this: produce the union of four queries each of which returned a variable number of two field records, (the first number being a telephone prefix, and the second being an ID that represented its pricing model) then join that data together to form a string key that could be used in a hash lookup to determine if the data was already in the cache.

Some other ideas:

use the queries themselves as the key into the cache instead of the results
since most of the data is sorted already, instead of just pushing onto the end, insert them at the correct place

and, inspired by a recent QOTW ... it shouldn't matter that the data are sorted asciibetically, just that they're sorted the same way each time. So you can do something like this:

use List::Util qw(shuffle);
my $alphabet = join '', shuffle 'a'..'z';  # do this only once and sav
+e it to a file for later reading

my $t;
@union = map { $_->[1] }
         sort { $a->[0] cmp $b->[0] }
         map { eval "(\$t = lc \$_) =~ tr/$alphabet/a-z/"; [ $t, $_ ] 
+}
         @union;
[download]

Not sure if there's a win there or not, but it's interesting anyway :)

duff

In reply to Re: Bitten by the worst case (or why it pays to know whats inside the black box) by duff
in thread Bitten by the worst case (or why it pays to know whats inside the black box) by demerphq

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