[IMPALA-5918] Improve the documentation around REFRESH and INVALIDATE METADATA

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.9.0
• Fix Version/s: Impala 2.13.0, Impala 3.1.0
• Component/s: Docs
• Epic Color: ghx-label-8
• Assignee: Alexandra Rodoni
• Reporter: Dimitris Tsirogiannis
• Created: 11/Sep/17 17:14
• Updated: 09/Jun/18 00:20
• Resolved: 09/Jun/18 00:20

Description

The documentation of REFRESH does not seem to explicitly mention that REFRESH can also detect file modifications and deletions as long as the modifications are not a result of hdfs rebalancer. In some cases, users are confused and so they end up using INVALIDATE METADATA even though they should be using REFRESH instead. We should expand the documentation of REFRESH to include all use cases.