The idea behind the eval blocks is to add a layer of abstraction so that when I need to add additional statistical analyses I can add entries to mysql with the proper eval string.

The most effective optimisation would be to avoid (re)-evaling your snippets for every id.

And the easiest way to do that would be to construct your snippets so that they can be eval'd into subroutines once each, and then you can call the appropriate subroutine for each ID instead.

As you haven't posted your snippets, I can't offer a realistic example, but by way of giving you an idea, something line:

$_ = sub{ $_ } for keys %{$agg_snippets};
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Would (assuming the snippets are correctly defined, turn the snippets into subroutines.

You then just invoke the appropriate subroutine passing the data as arguments; and your code should run substantially faster.