RE: floating point and Sun T2000

  • From: Michael Ebert <mebert@xxxxxxxxxxx>
  • To: kevinc@xxxxxxxxxxxxx, oracle-l@xxxxxxxxxxxxx
  • Date: Fri, 5 May 2006 19:50:30 +0200

What does "FP underpinnings for scalability" mean? If you're concerned 
about performance, it is quite likely that FP operations are faster than 
integer operations with the same size on any hardware built in the last 10 
years. Also I'd be surprised at a CPU bigger than those used in cell 
phones that can't do FP ops in hardware. 

The famous Pentium FP bug, by the way, occurred only under very special 
circumstances - it was discovered when calculating pi to millions of 
digits. Even if you were running Oracle on one of those, there would 
probably be a dozen other issues that should worry you more.

Dr. Michael Ebert
DB2 & Oracle Database Administrator
aMaDEUS Data Processing
Erding / Munich, Germany








"Kevin Closson" <kevinc@xxxxxxxxxxxxx>
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05-05-06 19:22

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Subject
RE: floating point and Sun T2000






>>>> >>>I'm testing a Sun T2000 Solaris 10 Oracle 10g and have 
>>>read that if 
>>>> >>>floating point calculations are used then the box is 
>>>essentially a 
>>>> >>>1 cpu box.
>>>>
>>>> the database server does not do floating point calculations

...The question implied a scalability concern, right? My point is
that the engine does not have FP underpinnings for scalability. You
know, those things that happen, uh, like millions of times per second
like spinlocks, dba hashing, chain walks, etc.  Of course I know about
things like BINARY_FLOAT and BINARY_DOUBLE datatypes, but I can't see
how these could ever be used to the point of rendering poor scalability.
Every time one of these data types is touched it is preceded by myriads
of integer ops. Tell me if I'm wrong by all means.

I know one thing for certain, we should all be glad the server doesn't
use floating point and that the NUMBER datatype is the way it is,
because that nasty little floating point bug in the pentium processor 
back in the late 90s would have been a REAL pill to
swallow.  Come to think of it, these new 10g datatypes would have been
really freaky on those buggy pentiums :-)

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