Zoltán Borók-Nagy created IMPALA-11797: ------------------------------------------
Summary: LEFT ANTI JOIN's selectivity is always 1.0 Key: IMPALA-11797 URL: https://issues.apache.org/jira/browse/IMPALA-11797 Project: IMPALA Issue Type: Bug Components: Frontend Reporter: Zoltán Borók-Nagy We use the [following formula|https://github.com/apache/impala/blob/b88cfadbbde45ccbe5e4b6d644d046a9a275e31c/fe/src/main/java/org/apache/impala/planner/JoinNode.java#L690] to calculate the LEFT ANTI JOIN's selectivity: {noformat} selectivity = (double) Math.max(lhsNdv - rhsNdv, lhsNdv) / (double) lhsNdv; {noformat} {{Math.max(lhsNdv - rhsNdv, lhsNdv)}} is always equals to {{lhsNdv}}, hence the formula becomes: {noformat} lhsNdv / lhsNdv {noformat} which is always 1.0. We should come up with a better formula. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org