Re: [HACKERS] regression bigtest needs very long time

Thomas Lockhart <lockhart@alumni.caltech.edu> writes:
>> > The question, though, becomes what percentage of operations on a
>> > NUMERIC field are arithmetic, and what percentage are storage/retrieval.
>> Good point.
>We assume that most data stays inside the database on every query.
>That is, one should optimize for comparison/calculation speed, not
>formatting speed. If you are comparing a bunch of rows to return one,
>you will be much happier if the comparison happens quickly, as opposed
>to doing that slowly but formatting the single output value quickly.
>An RDBMS can't really try to optimize for the opposite case, since
>that isn't how it is usually used...

The optimizations under discussion will not significantly affect comparison
speed one way or the other, so comparison speed is a moot issue.

The question, really, is how often do you do this:
   select bignum from table where key = condition

versus this:
   select bignum1/bignum2 from table where key = condition

or this:
   select * from table where bignum1/bignum2 = condition

-Michael Robinson