stevenzwu commented on code in PR #10331: URL: https://github.com/apache/iceberg/pull/10331#discussion_r1602342274
########## flink/v1.19/flink/src/main/java/org/apache/iceberg/flink/sink/shuffle/StatisticsType.java: ########## @@ -0,0 +1,55 @@ +/* + * 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.flink.sink.shuffle; + +/** + * Range distribution requires gathering statistics on the sort keys to determine proper range + * boundaries to distribute/cluster rows before writer operators. + */ +public enum StatisticsType { + /** + * Tracks the data statistics as {@code Map<SortKey, Long>} frequency. It works better for + * low-cardinality scenarios (like country, event_type, etc.) where the cardinalities are in + * hundreds or thousands. + * + * <ul> + * <li>Pro: accurate measurement on the statistics/weight of every key. + * <li>Con: memory footprint can be large if the key cardinality is high. + * </ul> + */ + Map, + + /** + * Sample the sort keys via reservoir sampling. Then split the range partitions via range bounds + * from sampled values. It works better for high-cardinality scenarios (like device_id, user_id, + * uuid etc.) where the cardinalities can be in millions or billions. + * + * <ul> + * <li>Pro: relatively low memory footprint for high-cardinality sort keys. + * <li>Con: memory footprint can be large if the key cardinality is high. Review Comment: thanks for catching it. I misread the code context earlier. -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
