[CALCITE-3909] RelMdMinRowCount doesn't take into account UNION DISTINCT

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.22.0
• Fix Version/s: 1.23.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Chunwei Lei
• Reporter: Chunwei Lei
• Created: 10/Apr/20 11:52
• Updated: 24/May/20 11:59
• Resolved: 14/Apr/20 02:15

Description

When computing minRowCount for Union, it doesn't task into account UNION DISTINCT.

public Double getMinRowCount(Union rel, RelMetadataQuery mq) {
  double rowCount = 0.0;
  for (RelNode input : rel.getInputs()) {
    Double partialRowCount = mq.getMinRowCount(input);
    if (partialRowCount != null) {
      rowCount += partialRowCount;
    }
  }
  return rowCount;
}

Issue Links

• links to: GitHub Pull Request #1907