VariableInstanceLog table in BPM Suite/RHPAM truncates process variable values if they go beyond 255 characters

Issue

• It has been observed that VariableInstanceLog table in BPMS 6.0.x truncates process variable values if they go beyond 255 characters ;
• The Value and OldValue column in VARIABLEINSTANCELOG table is of type VARCHAR which can hold value up to 32767 characters long (DB2). But our string length is 200,000. If we store 200,000 length character in the value column it is storing first 32767 character and the remaining characters are truncated because the datatype is VARCHAR and it can hold up to 32767;

• BPM Suite 6 provides the following REST API to retrieve the process variables.

  /business-central/rest/history/instance/xxx/variable/yyZZZ
  

  However, when using the same API to retrieve a value of a process variable (of String type) the result is truncated on return. It does not cause the same issue for all the process variables, but rather those variables which store quite large String, even it seems to have a limitation for storing characters up to a limit of 255 characters.

• We see the following message in logs when we set a value with a length greater than 255 for a process variable:

  WARN  [org.jbpm.process.audit.VariableInstanceLog] (http-10.0.0.1:8080-2) Variable content was trimmed as it was too long (more than 255 characters)