filtering out "bad" regular expressions from user input

[Aahz Maruch]

In article <mailman.970252786.23630.python-list at python.org>,
Skip Montanaro  <skip at mojam.com> wrote:
>
>As usual, I specified the problem incompletely.  The problem isn't so much
>regular expressions that perform poorly when matched against particular
>strings.  It is that some very simple regular expressions (like ".*") can
>match all (or almost all) records in a database of 20,000 or so rows.
>Marshalling and returning that amount of information from MySQL to my
>front-end code takes a substantial amount of time, as you might imagine.

I'd suggest using a cursor (or perhaps MySQL supports TOP or the
equivalent) and just returning a subset.  You'd probably want to present
a comment such as "Returning top 1000 rows of 23000 records that match
your query".
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