[IMPALA-9903] Queries on a Kudu table call openTable multiple times

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 3.4.0
• Fix Version/s: Impala 4.0.0
• Component/s: Frontend
• Labels: kudu performance
• Epic Color: ghx-label-1
• Assignee: Grant Henke
• Reporter: Grant Henke
• Created: 27/Jun/20 03:26
• Updated: 09/Nov/20 15:42
• Resolved: 09/Nov/20 15:42

Description

When testing the results of KUDU-1802 I saw that each query ran would result in 5 GetTableSchema requests to the Kudu master server. The request comes from each KuduClient.openTable call in the Impala frontend.
https://github.com/apache/impala/search?l=Java&q=openTable

Ideally Impala would only call KuduClient.openTable once and then use the returned KuduTable object for the length of the query. That would result in 5x fewer remote RPC calls to the Kudu master server per query.

Issue Links

• relates to: KUDU-1802 Deserializing scan tokens should avoid round-trip to master