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From Vladimir Sitnikov <>
Subject Re: JdbcSort not used in plan.
Date Wed, 11 Mar 2015 19:30:09 GMT
>Every extra variable (e.g. column count) you add is a new
opportunity for something to go wrong.

I see that, however you need something to make project that reduces
columns cheaper, don't you?
On the other hand, if you use (rows, cpu) costing tuple, what would
you consider cheaper (2 rows, 3 cpu) or (3 rows, 2 cpu)?
The easiest way to compare costs is to use "rows + X*cpu" formula,
that basically requires some coefficient.

> query failed to use JdbcSort
Well, I just picked a first JdbcTest test that did instantiate JdbcSort.
Of course we need a separate issue for sorting (i.e. simplest case for it).


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