com.facebook.presto.druid.DruidProjectExpressionConverter Maven / Gradle / Ivy
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.druid;
import com.facebook.presto.druid.DruidQueryGeneratorContext.Selection;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.function.FunctionHandle;
import com.facebook.presto.spi.function.StandardFunctionResolution;
import com.facebook.presto.spi.relation.CallExpression;
import com.facebook.presto.spi.relation.ConstantExpression;
import com.facebook.presto.spi.relation.InputReferenceExpression;
import com.facebook.presto.spi.relation.LambdaDefinitionExpression;
import com.facebook.presto.spi.relation.RowExpression;
import com.facebook.presto.spi.relation.RowExpressionVisitor;
import com.facebook.presto.spi.relation.SpecialFormExpression;
import com.facebook.presto.spi.relation.VariableReferenceExpression;
import com.facebook.presto.spi.type.StandardTypes;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.spi.type.TypeManager;
import com.google.common.collect.ImmutableSet;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import static com.facebook.presto.druid.DruidErrorCode.DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION;
import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
class DruidProjectExpressionConverter
implements RowExpressionVisitor>
{
private static final Set TIME_EQUIVALENT_TYPES = ImmutableSet.of(StandardTypes.BIGINT, StandardTypes.INTEGER, StandardTypes.TINYINT, StandardTypes.SMALLINT);
protected final TypeManager typeManager;
protected final StandardFunctionResolution standardFunctionResolution;
public DruidProjectExpressionConverter(
TypeManager typeManager,
StandardFunctionResolution standardFunctionResolution)
{
this.typeManager = requireNonNull(typeManager, "type manager");
this.standardFunctionResolution = requireNonNull(standardFunctionResolution, "standardFunctionResolution is null");
}
@Override
public DruidExpression visitVariableReference(
VariableReferenceExpression reference,
Map context)
{
Selection input = requireNonNull(context.get(reference), format("Input column %s does not exist in the input", reference));
return new DruidExpression(input.getDefinition(), input.getOrigin());
}
@Override
public DruidExpression visitLambda(
LambdaDefinitionExpression lambda,
Map context)
{
throw new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "Druid does not support lambda: " + lambda);
}
protected boolean isImplicitCast(Type inputType, Type resultType)
{
if (typeManager.canCoerce(inputType, resultType)) {
return true;
}
return resultType.getTypeSignature().getBase().equals(StandardTypes.TIMESTAMP) && TIME_EQUIVALENT_TYPES.contains(inputType.getTypeSignature().getBase());
}
private DruidExpression handleCast(
CallExpression cast,
Map context)
{
if (cast.getArguments().size() == 1) {
RowExpression input = cast.getArguments().get(0);
Type expectedType = cast.getType();
if (isImplicitCast(input.getType(), expectedType)) {
return input.accept(this, context);
}
throw new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "Non implicit casts not supported: " + cast);
}
throw new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "This type of CAST operator not supported: " + cast);
}
protected Optional basicCallHandling(CallExpression call, Map context)
{
FunctionHandle functionHandle = call.getFunctionHandle();
if (standardFunctionResolution.isNotFunction(functionHandle) || standardFunctionResolution.isBetweenFunction(functionHandle)) {
throw new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "Unsupported function in Druid aggregation: " + functionHandle);
}
if (standardFunctionResolution.isCastFunction(functionHandle)) {
return Optional.of(handleCast(call, context));
}
return Optional.empty();
}
@Override
public DruidExpression visitInputReference(
InputReferenceExpression reference,
Map context)
{
throw new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "Input reference not supported: " + reference);
}
@Override
public DruidExpression visitSpecialForm(
SpecialFormExpression specialForm,
Map context)
{
throw new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "Special form not supported: " + specialForm);
}
@Override
public DruidExpression visitCall(CallExpression call, Map context)
{
return basicCallHandling(call, context).orElseThrow(() -> new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "Call not supported: " + call));
}
@Override
public DruidExpression visitConstant(ConstantExpression literal, Map context)
{
throw new PrestoException(DRUID_PUSHDOWN_UNSUPPORTED_EXPRESSION, "Constant not supported: " + literal);
}
}
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