The only thing you're adding to the query is a second SORT step, so it shouldn't require any more time/memory than the query's first SORT
did.
Interesting -- I wonder if it would be possible for the optimizer to detect this and avoid the redundant inner sort ... (/me muses to himself)
That's somethign I've wondered myself as well. Also - I wonder if the optimiser could be made smart enough to push down the outer LIMIT and OFFSET clauses into the subquery.
Chris
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