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By default all values in the HiveConf object are converted to environment variables of the same name as the key (with '.' (dot) converted to '_' (underscore)) and set as part of the script operator's environment. However, some values can grow large or are not amenable to translation to environment variables. This value gives a comma separated list of configuration values that will not be set in the environment when calling a script operator. By default the valid transaction list is excluded, as it can grow large and is sometimes compressed, which does not translate well to an environment variable.
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