Java Code Examples for org.apache.calcite.rel.metadata.RelMetadataQuery#getTableOrigin()

/**
 * Retrieves join factors that correspond to simple table references. A
 * simple table reference is a single table reference with no grouping or
 * aggregation.
 *
 * @param multiJoin join factors being optimized
 *
 * @return map consisting of the simple factors and the tables they
 * correspond
 */
private Map<Integer, RelOptTable> getSimpleFactors(RelMetadataQuery mq, LoptMultiJoin multiJoin) {
  final Map<Integer, RelOptTable> returnList = new HashMap<>();

  // Loop through all join factors and locate the ones where each
  // column referenced from the factor is not derived and originates
  // from the same underlying table.  Also, discard factors that
  // are null-generating or will be removed because of semijoins.
  if (multiJoin.getMultiJoinRel().isFullOuterJoin()) {
    return returnList;
  }
  for (int factIdx = 0; factIdx < multiJoin.getNumJoinFactors(); factIdx++) {
    if (multiJoin.isNullGenerating(factIdx)
        || (multiJoin.getJoinRemovalFactor(factIdx) != null)) {
      continue;
    }
    final RelNode rel = multiJoin.getJoinFactor(factIdx);
    final RelOptTable table = mq.getTableOrigin(rel);
    if (table != null) {
      returnList.put(factIdx, table);
    }
  }

  return returnList;
}
 

/**
 * Determines whether a join is a removable self-join. It is if it's an
 * inner join between identical, simple factors and the equality portion of
 * the join condition consists of the same set of unique keys.
 *
 * @param joinRel the join
 *
 * @return true if the join is removable
 */
public static boolean isRemovableSelfJoin(Join joinRel) {
  final RelNode left = joinRel.getLeft();
  final RelNode right = joinRel.getRight();

  if (joinRel.getJoinType() != JoinRelType.INNER) {
    return false;
  }

  // Make sure the join is between the same simple factor
  final RelMetadataQuery mq = joinRel.getCluster().getMetadataQuery();
  final RelOptTable leftTable = mq.getTableOrigin(left);
  if (leftTable == null) {
    return false;
  }
  final RelOptTable rightTable = mq.getTableOrigin(right);
  if (rightTable == null) {
    return false;
  }
  if (!leftTable.getQualifiedName().equals(rightTable.getQualifiedName())) {
    return false;
  }

  // Determine if the join keys are identical and unique
  return areSelfJoinKeysUnique(mq, left, right, joinRel.getCondition());
}
 

/**
 * Retrieves join factors that correspond to simple table references. A
 * simple table reference is a single table reference with no grouping or
 * aggregation.
 *
 * @param multiJoin join factors being optimized
 *
 * @return map consisting of the simple factors and the tables they
 * correspond
 */
private Map<Integer, RelOptTable> getSimpleFactors(RelMetadataQuery mq, LoptMultiJoin multiJoin) {
  final Map<Integer, RelOptTable> returnList = new HashMap<>();

  // Loop through all join factors and locate the ones where each
  // column referenced from the factor is not derived and originates
  // from the same underlying table.  Also, discard factors that
  // are null-generating or will be removed because of semijoins.
  if (multiJoin.getMultiJoinRel().isFullOuterJoin()) {
    return returnList;
  }
  for (int factIdx = 0; factIdx < multiJoin.getNumJoinFactors(); factIdx++) {
    if (multiJoin.isNullGenerating(factIdx)
        || (multiJoin.getJoinRemovalFactor(factIdx) != null)) {
      continue;
    }
    final RelNode rel = multiJoin.getJoinFactor(factIdx);
    final RelOptTable table = mq.getTableOrigin(rel);
    if (table != null) {
      returnList.put(factIdx, table);
    }
  }

  return returnList;
}
 

/**
 * Determines whether a join is a removable self-join. It is if it's an
 * inner join between identical, simple factors and the equality portion of
 * the join condition consists of the same set of unique keys.
 *
 * @param joinRel the join
 *
 * @return true if the join is removable
 */
public static boolean isRemovableSelfJoin(Join joinRel) {
  final RelNode left = joinRel.getLeft();
  final RelNode right = joinRel.getRight();

  if (joinRel.getJoinType().isOuterJoin()) {
    return false;
  }

  // Make sure the join is between the same simple factor
  final RelMetadataQuery mq = joinRel.getCluster().getMetadataQuery();
  final RelOptTable leftTable = mq.getTableOrigin(left);
  if (leftTable == null) {
    return false;
  }
  final RelOptTable rightTable = mq.getTableOrigin(right);
  if (rightTable == null) {
    return false;
  }
  if (!leftTable.getQualifiedName().equals(rightTable.getQualifiedName())) {
    return false;
  }

  // Determine if the join keys are identical and unique
  return areSelfJoinKeysUnique(mq, left, right, joinRel.getCondition());
}
 

/** Tests calling {@link RelMetadataQuery#getTableOrigin} for
 * an aggregate with no columns. Previously threw. */
@Test void testEmptyAggregateTableOrigin() {
  final FrameworkConfig config = RelBuilderTest.config().build();
  final RelBuilder builder = RelBuilder.create(config);
  RelMetadataQuery mq = builder.getCluster().getMetadataQuery();
  RelNode agg = builder
      .scan("EMP")
      .aggregate(builder.groupKey())
      .build();
  final RelOptTable tableOrigin = mq.getTableOrigin(agg);
  assertThat(tableOrigin, nullValue());
}