[IMPALA-11279] Optimize count(*) queries for Iceberg tables

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Resolved
• Fix Version/s: Impala 4.2.0
• Component/s: Frontend
• Labels: impala-iceberg
• Epic Color: ghx-label-4
• Assignee: Li Penglin
• Reporter: Zoltán Borók-Nagy
• Created: 03/May/22 15:02
• Updated: 25/Oct/22 09:26
• Resolved: 29/Jun/22 02:35

Description

Plain SELECT count FROM tbl; queries could be made superfast for Iceberg tables as they store the precise number of rows in table property 'numRows'.

So we could just answer such queries from table metadata.