On Tue, Jun 10, 2014 at 11:59:57AM +0100, Chris Jack wrote: >Can I suggest you consider including some rudimentary idea of "cost" >when you're deciding whether to allow the query to run or not. "Cost" >could be in terms of anticipated rows returned and/or total >anticipated CPU time.
Yeah, it shouldn't be that hard to write code to evaluate an expression and work out how long it'll take to run. :-) R