siddharthteotia commented on a change in pull request #4547: Indexed table URL: https://github.com/apache/incubator-pinot/pull/4547#discussion_r317844645
########## File path: pinot-core/src/main/java/org/apache/pinot/core/data/order/OrderByUtils.java ########## @@ -0,0 +1,295 @@ +/** + * 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.pinot.core.data.order; + +import java.util.Comparator; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import org.apache.commons.collections.comparators.ComparableComparator; +import org.apache.pinot.common.request.AggregationInfo; +import org.apache.pinot.common.request.SelectionSort; +import org.apache.pinot.common.utils.BytesUtils; +import org.apache.pinot.common.utils.DataSchema; +import org.apache.pinot.common.utils.primitive.ByteArray; +import org.apache.pinot.core.data.table.Record; +import org.apache.pinot.core.query.aggregation.function.AggregationFunction; +import org.apache.pinot.core.query.aggregation.function.AggregationFunctionUtils; + +import static org.apache.pinot.common.utils.DataSchema.*; + + +/** + * Helper methods to perform order by of list of {@link Record} + */ +public final class OrderByUtils { + + private OrderByUtils() { + } + + /** + * Constructs a comparator for ordering by the keys in the TableRecord::keys + */ + public static Comparator<Record> getKeysComparator(DataSchema dataSchema, List<SelectionSort> orderBy) { Review comment: DISTINCT is a specialized case of aggregation query where the result set will contain more than 1 row and thus we need a way to pass down order by info to aggregation query execution code path as well -- we haven't had to worry about this problem so far because other aggregation functions have resultset as exactly 1 row (and therefore we don't have to worry about order by). This needs to be solved for group by as well because the group by info is contained inside aggregation info and there are at least couple of places in the code where we assume the existence of agg info as an indication of non-existence of selection query -- and thus no way to retrieve selection sort sequence ---------------------------------------------------------------- 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] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
