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wt186005 6 posts Joined 08/14
16 Sep 2014
Histogram_Map function - need help

I am strugglign with this function.  My error is the following which confuses me because I thought those clauses were optional.
>[Error] Script lines: 1-6 --------------------------
[AsterData][NClusterJDBCDSII](34) ERROR: SQL-MR function HISTOGRAM_MAP failed: Please specify either the INTERVAL clause or all of the following clauses: BIN_SIZE, START_VALUE. () _
My data (p2p.wt_session_histogram) is simply 2 columns:
customer_id and cnt_sessions (integer count)
 
select *
from histogram_map
(
on p2p.wt_session_histogram
value_column ('cnt_sessions')
);
 

dnoeth 4628 posts Joined 11/04
16 Sep 2014

Not all those clauses are optional, they're just mutually exclusive.
The error message is correct, you have to specify either both BIN_SIZE and START_VALUE or INTERVALS.
If there was a default it might be the minimum value based on the data type (e.g. -2.147.483.648 for an INT) and a bin size of 1, you probbay don't want that :-)

Dieter

wt186005 6 posts Joined 08/14
18 Sep 2014

Thanks, Dieter! I was able to get it to run but I was expecting to get a graphical output: literally - a histogram.  Do you know if an Aster function that will generate this?  Thanks, Wendy

dnoeth 4628 posts Joined 11/04
19 Sep 2014

Hi Wendy,
the histogram_map/histogram_reduce combination only creates tabular output.
As Aster Lens only supports NpathViz and CFilterViz output you need a visualization tool to get graphical output.

Dieter

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