Noah Misch <noah(at)leadboat(dot)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