wuwenchi commented on code in PR #5120: URL: https://github.com/apache/iceberg/pull/5120#discussion_r907983189
########## flink/v1.15/flink/src/main/java/org/apache/iceberg/flink/sink/PartitionTransformUdf.java: ########## @@ -0,0 +1,50 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 Licenet ideajoinet ideajoin for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.iceberg.flink.sink; + +import org.apache.flink.table.annotation.DataTypeHint; +import org.apache.flink.table.annotation.InputGroup; +import org.apache.flink.table.functions.ScalarFunction; +import org.apache.iceberg.expressions.Literals; +import org.apache.iceberg.transforms.Transform; +import org.apache.iceberg.transforms.Transforms; +import org.apache.iceberg.types.Type; +import org.apache.iceberg.types.TypeUtil; + +public class PartitionTransformUdf { + + public static class Truncate extends ScalarFunction { + public String eval(int num, @DataTypeHint(inputGroup = InputGroup.ANY) Object obj) { Review Comment: > can we define our own InputGroup We can customize input and output by overriding `getTypeInference` method: ```java @Override public TypeInference getTypeInference(DataTypeFactory typeFactory) { return TypeInference.newBuilder() .inputTypeStrategy(...) // custom input .outputTypeStrategy(...) // custom outpout .build(); } ``` > And if we did, would the SQL compiler fail to build the program or would it still just fail at runtime? If you throw an exception in `inferInputTypes`, then flink will throw exception and terminate the program: ```java @Override public TypeInference getTypeInference(DataTypeFactory typeFactory) { return TypeInference.newBuilder() .inputTypeStrategy(new InputTypeStrategy() { ... @Override public Optional<List<DataType>> inferInputTypes(CallContext callContext, boolean throwOnFailure) { throw new UnsupportedOperationException("exception"); } ... }) .build(); } org.apache.flink.table.api.ValidationException: SQL validation failed. ... Caused by: java.lang.UnsupportedOperationException: exception ``` > I guess if the annotation is tightened, what will flink do when it goes to compile a program out of SQL that passes the wrong type to a DataHint? Yes, if parameter type is not matched `eval`'s parameter type , flink will throw an exception directly: ``` org.apache.flink.table.api.ValidationException: SQL validation failed. Invalid function call ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
