It does what I want (I think!) but runs unacceptably slowly on large volumes. I suspect that my regular expression is not helping.

Check out that suspicion before you start hacking on code.

If you're really getting data via DBI, particularly if you're going over the network, the overhead to get a row of data is very likely to dwarf any per-row computation you're doing. You can check that by measuring the time it takes to fetch that large volume of data without processing. Then compare that to the time you've measured for fetch+processing.

In reply to Re: Discovering minimal relational data types on large volumes by dws
in thread Discovering minimal relational data types on large volumes by dbush

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