CQL - StandardDeviation Operator Doesn't Scale (Doc ID 1510164.1)

Last updated on JULY 14, 2015

Applies to:

Oracle Event Processing - Version 11.1.1.7.0 and later
Information in this document applies to any platform.

Symptoms

On : 11.1.1.6.0 version, CEP system

ACTUAL BEHAVIOR
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The standardDeviation aggregator keeps the individual values, and recalculates the output based on every value. This doesn't scale. Not only does it require storage for all of the values (which will grow until OOME for a stream), it re-calculates the result from every value for each event.


EXPECTED BEHAVIOR
-----------------------
standardDeviation should scale the value.

STEPS
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The issue can be reproduced at will with the following steps:
1. Create a standardDeviation aggregator
2. Notice it won't scale the value.

BUSINESS IMPACT
-----------------------
The issue has the following business impact:
Due to this issue, users cannot use the OOB standardDeviation aggregator.

Cause

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