On Mon, Jun 15, 2009 at 10:00 PM, David Fetter
<david@fetter.org> wrote:
On Mon, Jun 15, 2009 at 11:34:38AM -0400, Tom Lane wrote:
> David Fetter <
david@fetter.org> writes:
> > * It's going to a lot of trouble to allow for the possibility of both
> > unordered results and of duplicate lines. If we disallow duplicate
> > lines in unordered result sets, we can get a big speed gain by using
> > hash-based comparisons.
>
> Why not just sort the lines and compare?
Please find attached the updated script and test cases. Changes since last submission:
.) Script uses tabs for indentation.
.) Script almost passes
perlcritic.com at 'stern' level.
.) Correct some RE matches, so that a ? mark only at the beginning of the line matches (^ anchor).
.) Employ hybrid approach to support RE in unordered set, and to get better performance:
If there's no RE line in an unordered group of lines then perform sort on both arrays and then compare. If there _is_ an RE line in unordered group of lines, then do the O(n^2) processing to eliminate common lines and then report on missing lines.
TODO:
.) Using Tie::File to make code a little cleaner.
I agree that the choice of the hybrid approach for Unordered Set comparison makes script too indented, and maybe a little hard on eyes, but it's pretty simple and I have tried to delineate the major sections with proper comments.
Best regards,
--
Lets call it Postgres
EnterpriseDB
http://www.enterprisedb.comgurjeet[.singh]@EnterpriseDB.com
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