How to use

getJoinDistinctRowCount

method

in

org.apache.calcite.rel.metadata.RelMdUtil

@Override
public Double getDistinctRowCount(Join rel, RelMetadataQuery mq, ImmutableBitSet groupKey,
  RexNode predicate) {
 if (rel instanceof HiveJoin) {
  HiveJoin hjRel = (HiveJoin) rel;
  //TODO: Improve this
  if (rel instanceof SemiJoin) {
   return mq.getDistinctRowCount(hjRel.getLeft(), groupKey,
     rel.getCluster().getRexBuilder().makeLiteral(true));
  } else {
   return RelMdUtil.getJoinDistinctRowCount(mq, rel, rel.getJoinType(),
     groupKey, predicate, true);
  }
 }
 return mq.getDistinctRowCount(rel, groupKey, predicate);
}

@Override
public Double getDistinctRowCount(Join rel, RelMetadataQuery mq, ImmutableBitSet groupKey,
  RexNode predicate) {
 if (rel instanceof HiveJoin) {
  HiveJoin hjRel = (HiveJoin) rel;
  //TODO: Improve this
  if (rel instanceof SemiJoin) {
   return mq.getDistinctRowCount(hjRel.getLeft(), groupKey,
     rel.getCluster().getRexBuilder().makeLiteral(true));
  } else {
   return RelMdUtil.getJoinDistinctRowCount(mq, rel, rel.getJoinType(),
     groupKey, predicate, true);
  }
 }
 return mq.getDistinctRowCount(rel, groupKey, predicate);
}

public Double getDistinctRowCount(Join rel, RelMetadataQuery mq,
  ImmutableBitSet groupKey, RexNode predicate) {
 if (predicate == null || predicate.isAlwaysTrue()) {
  if (groupKey.isEmpty()) {
   return 1D;
  }
 }
 return RelMdUtil.getJoinDistinctRowCount(mq, rel, rel.getJoinType(),
   groupKey, predicate, false);
}

public Double getDistinctRowCount(Join rel, RelMetadataQuery mq,
  ImmutableBitSet groupKey, RexNode predicate) {
 if (predicate == null || predicate.isAlwaysTrue()) {
  if (groupKey.isEmpty()) {
   return 1D;
  }
 }
 return RelMdUtil.getJoinDistinctRowCount(mq, rel, rel.getJoinType(),
   groupKey, predicate, false);
}

@Override
public Double getDistinctRowCount(Join rel, ImmutableBitSet groupKey,
  RexNode predicate) {
 if (rel instanceof HiveJoin) {
  HiveJoin hjRel = (HiveJoin) rel;
  //TODO: Improve this
  if (hjRel.isLeftSemiJoin()) {
   return RelMetadataQuery.getDistinctRowCount(hjRel.getLeft(), groupKey,
     rel.getCluster().getRexBuilder().makeLiteral(true));
  } else {
   return RelMdUtil.getJoinDistinctRowCount(rel, rel.getJoinType(),
     groupKey, predicate, true);
  }
 }
 return RelMetadataQuery.getDistinctRowCount(rel, groupKey, predicate);
}