abstractdog commented on a change in pull request #1649: URL: https://github.com/apache/hive/pull/1649#discussion_r530182438
########## File path: ql/src/java/org/apache/hadoop/hive/ql/exec/vector/ptf/VectorPTFEvaluatorBytesCountDistinct.java ########## @@ -0,0 +1,42 @@ +/* + * 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.hadoop.hive.ql.exec.vector.ptf; + +import org.apache.hadoop.hive.ql.exec.vector.BytesColumnVector; +import org.apache.hadoop.hive.ql.exec.vector.ColumnVector; +import org.apache.hadoop.hive.ql.exec.vector.expressions.VectorExpression; +import org.apache.hadoop.hive.ql.plan.ptf.WindowFrameDef; +import org.apache.hive.common.util.Murmur3; + +/** + * Bytes (String) implementation for VectorPTFEvaluatorCountDistinct. + */ +public class VectorPTFEvaluatorBytesCountDistinct extends VectorPTFEvaluatorCountDistinct { + + public VectorPTFEvaluatorBytesCountDistinct(WindowFrameDef windowFrameDef, + VectorExpression inputVecExpr, int outputColumnNum) { + super(windowFrameDef, inputVecExpr, outputColumnNum); + resetEvaluator(); + } + + protected Object getValue(ColumnVector colVector, int i) { + BytesColumnVector inV = (BytesColumnVector) colVector; + return Murmur3.hash32(inV.vector[i], inV.start[i], inV.length[i], Murmur3.DEFAULT_SEED); Review comment: I used hashing for memory considerations, I was hoping that this way the unique set will consume less memory (storing hashes instead of strings of arbitrary length)...now I think that we could be fine with storing strings and prevent additional hashing, as we tend to optimize CPU cycles instead of memory in the very-first round...I'll change this to new String(byte[]) ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
