Noah Misch <n...@leadboat.com> wrote: > On Fri, Mar 02, 2012 at 03:45:38PM -0500, Robert Haas wrote: >> SELECT SUM(1) FROM (SELECT * FROM randomtext ORDER BY t) x; >> [13% faster with patch for C collation; 7% faster for UTF8] >> I had hoped for more like a 15-20% gain from this approach, but >> it didn't happen, I suppose because some of the instructions >> saved just resulted in more processor stalls. All the same, I'm >> inclined to think it's still worth doing. > > This is a border case, but I suggest that a 13% speedup on a > narrowly-tailored benchmark, degrading to 7% in common > configurations, is too meager to justify adopting this patch. We use the C collation and have character strings in most indexes and ORDER BY clauses. Unless there are significant contra- indications, I'm in favor of adopting this patch. -Kevin
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