Quanlong Huang created IMPALA-15182:
---------------------------------------
Summary: Uses HBO AggregationNode Cardinality in
Expr.getNumDistinctValues
Key: IMPALA-15182
URL: https://issues.apache.org/jira/browse/IMPALA-15182
Project: IMPALA
Issue Type: Improvement
Reporter: Quanlong Huang
Assignee: Quanlong Huang
Expr.getNumDistinctValues() returns the ndv for an Expr or a list of Exprs. We
can use the HBO stats on AggregationNode cardinalities to improve this.
[https://github.com/apache/impala/blob/21cd965f1670580f96d0ea846d9a2e83f66a2176/fe/src/main/java/org/apache/impala/analysis/Expr.java#L944-L956]
[https://github.com/apache/impala/blob/21cd965f1670580f96d0ea846d9a2e83f66a2176/fe/src/main/java/org/apache/impala/analysis/Expr.java#L633]
If the HMS stats are missing, we can use HBO stats for column ndvs at
[https://github.com/apache/impala/blob/21cd965f1670580f96d0ea846d9a2e83f66a2176/fe/src/main/java/org/apache/impala/analysis/SlotRef.java#L179]
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
