On 08/05/2014 12:56 AM, Mark Kirkwood wrote:
> The moral of the story for this case is that mapping Oracle to Postgres
> datatypes can require some careful thought. Using 'native' types (like
> integer, float8 etc) will generally give vastly quicker performance.
We've seen a lot of this ourselves. Oracle's NUMERIC is a native type,
whereas ours is emulated. From the performance, it would appear that
REAL is another calculated type.
At least you used INT though. I've seen too many Oracle shops using
NUMERIC in PostgreSQL because it's there, and suffering major
performance hits because of it.
That said, the documentation here says FLOAT4 is an alias for REAL, so
it's somewhat nonintuitive for FLOAT4 to be so much slower than FLOAT8,
which is an alias for DOUBLE PRECISION.
http://www.postgresql.org/docs/9.3/static/datatype.html
Not sure why that would be.
--
Shaun Thomas
OptionsHouse, LLC | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas@optionshouse.com
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