Examples with HiveApplyProjectionUtil io.trino.plugin.hive.HiveApplyProjectionUtil used on opensource projects

Example 1 with HiveApplyProjectionUtil

use of io.trino.plugin.hive.HiveApplyProjectionUtil in project trino by trinodb.

the class IcebergMetadata method applyProjection.

@Override
public Optional<ProjectionApplicationResult<ConnectorTableHandle>> applyProjection(ConnectorSession session, ConnectorTableHandle handle, List<ConnectorExpression> projections, Map<String, ColumnHandle> assignments) {
    if (!isProjectionPushdownEnabled(session)) {
        return Optional.empty();
    }
    // Create projected column representations for supported sub expressions. Simple column references and chain of
    // dereferences on a variable are supported right now.
    Set<ConnectorExpression> projectedExpressions = projections.stream().flatMap(expression -> extractSupportedProjectedColumns(expression).stream()).collect(toImmutableSet());
    Map<ConnectorExpression, ProjectedColumnRepresentation> columnProjections = projectedExpressions.stream().collect(toImmutableMap(Function.identity(), HiveApplyProjectionUtil::createProjectedColumnRepresentation));
    IcebergTableHandle icebergTableHandle = (IcebergTableHandle) handle;
    // all references are simple variables
    if (columnProjections.values().stream().allMatch(ProjectedColumnRepresentation::isVariable)) {
        Set<IcebergColumnHandle> projectedColumns = assignments.values().stream().map(IcebergColumnHandle.class::cast).collect(toImmutableSet());
        if (icebergTableHandle.getProjectedColumns().equals(projectedColumns)) {
            return Optional.empty();
        }
        List<Assignment> assignmentsList = assignments.entrySet().stream().map(assignment -> new Assignment(assignment.getKey(), assignment.getValue(), ((IcebergColumnHandle) assignment.getValue()).getType())).collect(toImmutableList());
        return Optional.of(new ProjectionApplicationResult<>(icebergTableHandle.withProjectedColumns(projectedColumns), projections, assignmentsList, false));
    }
    Map<String, Assignment> newAssignments = new HashMap<>();
    ImmutableMap.Builder<ConnectorExpression, Variable> newVariablesBuilder = ImmutableMap.builder();
    ImmutableSet.Builder<IcebergColumnHandle> projectedColumnsBuilder = ImmutableSet.builder();
    for (Map.Entry<ConnectorExpression, ProjectedColumnRepresentation> entry : columnProjections.entrySet()) {
        ConnectorExpression expression = entry.getKey();
        ProjectedColumnRepresentation projectedColumn = entry.getValue();
        IcebergColumnHandle baseColumnHandle = (IcebergColumnHandle) assignments.get(projectedColumn.getVariable().getName());
        IcebergColumnHandle projectedColumnHandle = createProjectedColumnHandle(baseColumnHandle, projectedColumn.getDereferenceIndices(), expression.getType());
        String projectedColumnName = projectedColumnHandle.getQualifiedName();
        Variable projectedColumnVariable = new Variable(projectedColumnName, expression.getType());
        Assignment newAssignment = new Assignment(projectedColumnName, projectedColumnHandle, expression.getType());
        newAssignments.putIfAbsent(projectedColumnName, newAssignment);
        newVariablesBuilder.put(expression, projectedColumnVariable);
        projectedColumnsBuilder.add(projectedColumnHandle);
    }
    // Modify projections to refer to new variables
    Map<ConnectorExpression, Variable> newVariables = newVariablesBuilder.buildOrThrow();
    List<ConnectorExpression> newProjections = projections.stream().map(expression -> replaceWithNewVariables(expression, newVariables)).collect(toImmutableList());
    List<Assignment> outputAssignments = newAssignments.values().stream().collect(toImmutableList());
    return Optional.of(new ProjectionApplicationResult<>(icebergTableHandle.withProjectedColumns(projectedColumnsBuilder.build()), newProjections, outputAssignments, false));
}