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From Alexandre Fouche <alexandre.fou...@cleverscale.com>
Subject Re: Multiple insert overwrite into multiple tables query stores same results in all tables
Date Sat, 10 Nov 2012 09:51:07 GMT
For information, i created https://issues.apache.org/jira/browse/HIVE-3699 


On Tuesday 6 November 2012 at 21:40, Alexandre Fouche wrote: 
> Hi,
> 
> I am doing a query with multiple INSERT OVERWRITE to multiple tables, in order to scan
the dataset only 1 time, and i end up having all these tables with the same content ! It seems
the GROUP BY query that returns results is overwriting all the tables.
> 
> This is the misbehaving query:
> 
>     FROM nikon
>     INSERT OVERWRITE TABLE e1
>     SELECT qs_cs_s_aid AS Emplacements, COUNT(*) AS Impressions WHERE qs_cs_s_cat='PRINT'
GROUP BY qs_cs_s_aid
>     INSERT OVERWRITE TABLE e2
>     SELECT qs_cs_s_aid AS Emplacements, COUNT(*) AS Vues WHERE qs_cs_s_cat='VIEW' GROUP
BY qs_cs_s_aid
>     ;
> 
> It launches only one MR job and here are the results. Why does table 'e1' contains results
from table 'e2' ?! Table 'e1' should have been empty (see individual SELECTs further below)
> 
>     hive> SELECT * from e1;
>     OK
>     NULL    2
>     1627575 25
>     1627576 70
>     1690950 22
>     1690952 42
>     1696705 199
>     1696706 66
>     1696730 229
>     1696759 85
>     1696893 218
>     Time taken: 0.229 seconds
> 
>     hive> SELECT * from e2;
>     OK
>     NULL    2
>     1627575 25
>     1627576 70
>     1690950 22
>     1690952 42
>     1696705 199
>     1696706 66
>     1696730 229
>     1696759 85
>     1696893 218
>     Time taken: 0.11 seconds
> 
> 
> Here is are the result to the indiviual queries (only the second query returns a result
set):
> 
>     hive> SELECT qs_cs_s_aid AS Emplacements, COUNT(*) AS Impressions FROM nikon WHERE
qs_cs_s_cat='PRINT' GROUP BY qs_cs_s_aid;
>     (...)
>     OK
>           <- There are no results, this is normal
>     Time taken: 41.471 seconds
> 
>     hive> SELECT qs_cs_s_aid AS Emplacements, COUNT(*) AS Vues FROM nikon WHERE qs_cs_s_cat='VIEW'
GROUP BY qs_cs_s_aid;
>     (...)
>     OK
>     NULL  2
>     1627575 25
>     1627576 70
>     1690950 22
>     1690952 42
>     1696705 199
>     1696706 66
>     1696730 229
>     1696759 85
>     1696893 218
>     Time taken: 39.607 seconds
> 
> 


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