JR46434 There are no warnings for potential precision loss in the Transformer

In a Transformer, Lookup, or Slowly Changing Dimension stage of a Parallel job,
input data may be assigned to an output data field that cannot contain it. 
For example, a field of type Integer may be derived from a BigInt. 
There are also cases where an arithmetic expression involving non-numeric fields 
uses an intermediate variable to do string-to-number and number-to-string 
conversion, leading to loss of precision owing to the data type used for the 
intermediate variable.

At run time, data that would overflow the output field is truncated or
modified to fit, without a warning being logged by the Transform operator. 
So for example an integer that is too large for the destination may become 
negative.

This change addresses the issue where implicit type conversion might lead to
data loss, but no warnings are issued to warn a user that this may occur.

The function of this change is to:
 - Generate compile-time warnings for potential data loss caused by implicit
   type conversions that are detected in expression.
 - Log a message at job runtime if such warnings have been generated,
   including the message contents.
 - Provide an option to disable the generation of warnings at compile time and
   logging these at run time.

The change will cause a warning file to be written a job?s RT_SCnn folder if
certain type conversion issues are detected in the Transformer, Lookup or 
Slowly Changing Dimension stages. This will only happen if the environment
variable APT_TRANSFORM_RANGE_CHECK is set to 1 at compile time. Setting 
APT_TRANSFORM_RANGE_CHECK=0, or not defining that variable at all, means the
warning files are not produced.

At job run time, the same environment variable can be used to control whether
a warning log message is issued or not. If APT_TRANSFORM_RANGE_CHECK is set to
1 a single message will be issued at runtime if any warning files exist in the
RT_SCnn folder of the job. 

IMPORTANT: Warning messages will only be generated for jobs that have been recompiled
with the environment variable APT_TRANSFORM_RANGE_CHECK set to 1.

For further details of the background to this issue, use of the new features,
and how to interpret the results, please refer to this Technote:
http://www-01.ibm.com/support/docview.wss?uid=swg21639629