On Sun, Jan 5, 2014 at 12:00 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Looking at this example makes me wonder if it wouldn't be worthwhile to provide a way to reset and re-use a tuplesort object, instead of redoing all the lookup work involved. Or maybe just find a way to cache the catalog lookups that are happening inside tuplesort_begin_datum, which are about 50% of that function's cost it looks like. We're paying this same kind of price for repeated tuplesort setup in the existing nodeAgg code, if we have an aggregate with ORDER BY or DISTINCT in a grouped query with many groups.
