Andres Freund <and...@anarazel.de> writes:
> On 2016-07-22 15:00:32 -0400, Tom Lane wrote:
>> Well, it's a question of whether an extra projection at the scan level is
>> worth the savings in column access during the sort or group stage.
> Well, the projection is what I was thinking of.
One point here is that unless your test case is a blind "SELECT *",
there's almost certainly going to be a projection before a sort anyway,
because we always want to get rid of any unreferenced columns to minimize
the data volume going through the sort.
regards, tom lane
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