nastra commented on a change in pull request #3023: URL: https://github.com/apache/iceberg/pull/3023#discussion_r712791299
########## File path: arrow/src/main/java/org/apache/iceberg/arrow/DictEncodedArrowConverter.java ########## @@ -0,0 +1,64 @@ +/* + * 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 License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.iceberg.arrow; + +import java.math.BigDecimal; +import org.apache.arrow.vector.DecimalVector; +import org.apache.arrow.vector.FieldVector; +import org.apache.iceberg.arrow.vectorized.ArrowVectorAccessor; +import org.apache.iceberg.arrow.vectorized.VectorHolder; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.types.Type; +import org.apache.iceberg.types.Types; + +/** + * This converts dictionary encoded arrow vectors to a correctly typed arrow vector. + */ +public class DictEncodedArrowConverter { + + private DictEncodedArrowConverter() { + } + + public static FieldVector toArrowVector(VectorHolder vectorHolder, ArrowVectorAccessor<?, String, ?, ?> accessor) { + Preconditions.checkArgument(null != vectorHolder, "VectorHolder cannot be null"); + Preconditions.checkArgument(null != accessor, "ArrowVectorAccessor cannot be null"); + // TODO: add conversions for other types (https://github.com/apache/iceberg/issues/2484) + if (vectorHolder.isDictionaryEncoded()) { + if (Type.TypeID.DECIMAL.equals(vectorHolder.icebergType().typeId())) { + int precision = ((Types.DecimalType) vectorHolder.icebergType()).precision(); + int scale = ((Types.DecimalType) vectorHolder.icebergType()).scale(); + + DecimalVector decimalVector = new DecimalVector( + vectorHolder.vector().getName(), + ArrowSchemaUtil.convert(vectorHolder.icebergField()).getFieldType(), + vectorHolder.vector().getAllocator()); Review comment: I was thinking about the same approach as you suggested when I was implementing this. However, when we reach this point, the `ArrowVectorAccessor` in this particular case is a `DictionaryDecimalIntAccessor` which holds an `IntVector` and not a `DecimalVector`, so we can't just pass the correct vector (or maybe I'm misunderstanding by what you mean with "just pass the correct vector"). In order to initialize the correct arrow vector (`DecimalVector` in this particular case), it's not enough to just know the `Type`. We actually need to know the entire `NestedField` to know if it's a required/optional field, hence the change around changing from `Type` to `NestedField` in the `VectorHolder`. -- 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]
