[IMPALA-7817] impala_config.sh appends to various env variables

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 3.0
• Fix Version/s: Impala 3.3.0
• Component/s: Infrastructure
• Epic Color: ghx-label-8
• Assignee: Unassigned
• Reporter: Michal Ostrowski
• Created: 06/Nov/18 16:24
• Updated: 23/Dec/20 21:40
• Resolved: 23/Dec/20 21:40

Description

If one repeatedly sources "bin/impala_config.sh", the script does not "set" environment variables, it frequently appends to them.  If one sources hits files repeatedly variables such as CLASSPATH keep growing and growing.

This is maybe a nuisance if CDH_BUILD_NUMBER hasn't changed, but if it has changed then the results can be unpredictable – because the resulting CLASSPATH will have the old CDH build number path included as well as the new one.

The proper solution (other than not depending on environment variables as much) is to write an "undo.sh" file of some sort that can be used to undo what impala_config.sh does.  Subsequently impala_config.sh can run an undo.sh to clean an environment before setting up a new one.