[IMPALA-10075] Reuse existing instances of unchanged partitions in REFRESH

• Type: Improvement
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: Impala 4.0.0
• Component/s: Catalog
• Epic Link: fine-grained metadata in catalogd
• Epic Color: ghx-label-3
• Assignee: Quanlong Huang
• Reporter: Quanlong Huang
• Created: 12/Aug/20 09:16
• Updated: 27/Oct/20 04:54
• Resolved: 27/Oct/20 04:54

Description

It's revealed by IMPALA-3127 that REFRESH will always update all partition instances (at least after IMPALA-9778). We should check if the new partition instance is the same as the original one, and only update them when needs. This reduce unneccessary catalog updates.