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From Guillaume Polaert <gpola...@cyres.fr>
Subject RE: Trouble with sum function
Date Mon, 11 Jun 2012 10:18:35 GMT
Thanks you, I didn't know about it.

Guillaume Polaert | Cyrès Conseil

De : Gabi D [mailto:gabid33@gmail.com]
Envoyé : lundi 11 juin 2012 12:14
À : user@hive.apache.org
Cc : Matouk Iftissen
Objet : Re: Trouble with sum function

float is known to have precision issues, because of the way it is implemented. If you are
working with money data you should definitely move to double.
google 'float precision' and you'll find a bunch of explanations.
On Mon, Jun 11, 2012 at 12:49 PM, Guillaume Polaert <gpolaert@cyres.fr<mailto:gpolaert@cyres.fr>>
wrote:
Hi,

We're expecting some issue with the sum function in Hive 0.7.1.
The precision of float number isn't correct (0.320484484676 instead of 0.32)
We aren't expecting this error with double format.

For instance, "select id, sum(col1), sum(col2) from test_table group by id" returns incorrect
values.

------
CREATE TABLE test_table  ( id int,  col1 double,  col2 float )
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\073'
LINES TERMINATED BY '\n'
STORED AS TEXTFILE;

LOAD DATA INPATH '/user/hive/xxxxx/import.csv' INTO TABLE `test _table`

Import.csv
1;1.012;1.012
2;2.1;2.1
3;3.2;3.2
4;4.323;4.323
5;5;5
----

Is it a bug  ? Or maybe did we make a error ?


Guillaume Polaert | Cyrès Conseil


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