Re: [HACKERS] regression bigtest needs very long time

Hi,

wieck@debis.com (Jan Wieck) wrote:
>
> Tom Lane wrote:
> > If we thought that the math functions (sqrt, exp, etc) for numerics
> > were really getting used for anything, it might also be fun to try
> > to put in some better algorithms for them.  I've got a copy of Cody
> > and Waite, which has been the bible for such things for twenty years.
> > But my guess is that it wouldn't be worth the trouble, except to the
> > extent that it speeds up the regression tests ;-)
>
(snip)
> 
>     Thus,  usually  the  precision  of float8 should be more than
>     enough for those calculations. Making NUMERIC able to  handle
>     these functions in it's extreme precision shouldn't really be
>     that time critical.
> 
  There are no problem concerning the NUMERIC test of INSERT/
SELECT and add/subtract/multiply/division. The only problem is
the processing time.
  One solution which solves this problem is to change the argument 
into *float8*. If the following changes are done, the processing 
will become high-speed than a previous about 10 times.  
  File     :"src/regress/sql/numeric.sql"  Statement:"INSERT INTO num_result SELECT id, 0,
POWER('10'::numeric,LN(ABS(round(val,300)))..."
 
  Change:   "LN(ABS(round(val,300))))"        to:   "LN(float8(ABS(round(va,300))))"
                            
# Another solution is to automatically convert the argument of the  LOG function into double precision data type in the
*inside*.(But, I do not know what kind of effect will be caused by this  solution.)
 

--
Regards.

SAKAIDA Masaaki <sakaida@psn.co.jp>
Osaka, Japan