Examples with HashToRandomExchangePrel org.apache.drill.exec.planner.physical.HashToRandomExchangePrel used on opensource projects

Example 1 with HashToRandomExchangePrel

use of org.apache.drill.exec.planner.physical.HashToRandomExchangePrel in project drill by apache.

the class InsertLocalExchangeVisitor method visitExchange.

@Override
public Prel visitExchange(ExchangePrel prel, Void value) throws RuntimeException {
    Prel child = ((Prel) prel.getInput()).accept(this, null);
    //   If DeMuxExchange is enabled, insert a UnorderedDeMuxExchangePrel after HashToRandomExchangePrel.
    if (!(prel instanceof HashToRandomExchangePrel)) {
        return (Prel) prel.copy(prel.getTraitSet(), Collections.singletonList(((RelNode) child)));
    }
    Prel newPrel = child;
    final HashToRandomExchangePrel hashPrel = (HashToRandomExchangePrel) prel;
    final List<String> childFields = child.getRowType().getFieldNames();
    List<RexNode> removeUpdatedExpr = null;
    if (isMuxEnabled) {
        // Insert Project Operator with new column that will be a hash for HashToRandomExchange fields
        final List<DistributionField> distFields = hashPrel.getFields();
        final List<String> outputFieldNames = Lists.newArrayList(childFields);
        final RexBuilder rexBuilder = prel.getCluster().getRexBuilder();
        final List<RelDataTypeField> childRowTypeFields = child.getRowType().getFieldList();
        final HashExpressionCreatorHelper<RexNode> hashHelper = new RexNodeBasedHashExpressionCreatorHelper(rexBuilder);
        final List<RexNode> distFieldRefs = Lists.newArrayListWithExpectedSize(distFields.size());
        for (int i = 0; i < distFields.size(); i++) {
            final int fieldId = distFields.get(i).getFieldId();
            distFieldRefs.add(rexBuilder.makeInputRef(childRowTypeFields.get(fieldId).getType(), fieldId));
        }
        final List<RexNode> updatedExpr = Lists.newArrayListWithExpectedSize(childRowTypeFields.size());
        removeUpdatedExpr = Lists.newArrayListWithExpectedSize(childRowTypeFields.size());
        for (RelDataTypeField field : childRowTypeFields) {
            RexNode rex = rexBuilder.makeInputRef(field.getType(), field.getIndex());
            updatedExpr.add(rex);
            removeUpdatedExpr.add(rex);
        }
        outputFieldNames.add(HashPrelUtil.HASH_EXPR_NAME);
        // distribution seed
        final RexNode distSeed = rexBuilder.makeBigintLiteral(BigDecimal.valueOf(HashPrelUtil.DIST_SEED));
        updatedExpr.add(HashPrelUtil.createHashBasedPartitionExpression(distFieldRefs, distSeed, hashHelper));
        RelDataType rowType = RexUtil.createStructType(prel.getCluster().getTypeFactory(), updatedExpr, outputFieldNames);
        ProjectPrel addColumnprojectPrel = new ProjectPrel(child.getCluster(), child.getTraitSet(), child, updatedExpr, rowType);
        newPrel = new UnorderedMuxExchangePrel(addColumnprojectPrel.getCluster(), addColumnprojectPrel.getTraitSet(), addColumnprojectPrel);
    }
    newPrel = new HashToRandomExchangePrel(prel.getCluster(), prel.getTraitSet(), newPrel, ((HashToRandomExchangePrel) prel).getFields());
    if (isDeMuxEnabled) {
        HashToRandomExchangePrel hashExchangePrel = (HashToRandomExchangePrel) newPrel;
        // Insert a DeMuxExchange to narrow down the number of receivers
        newPrel = new UnorderedDeMuxExchangePrel(prel.getCluster(), prel.getTraitSet(), hashExchangePrel, hashExchangePrel.getFields());
    }
    if (isMuxEnabled) {
        // remove earlier inserted Project Operator - since it creates issues down the road in HashJoin
        RelDataType removeRowType = RexUtil.createStructType(newPrel.getCluster().getTypeFactory(), removeUpdatedExpr, childFields);
        ProjectPrel removeColumnProjectPrel = new ProjectPrel(newPrel.getCluster(), newPrel.getTraitSet(), newPrel, removeUpdatedExpr, removeRowType);
        return removeColumnProjectPrel;
    }
    return newPrel;
}