Ferrari6 commented on a change in pull request #7409: URL: https://github.com/apache/pinot/pull/7409#discussion_r705839273
########## File path: pinot-common/src/main/java/org/apache/pinot/common/function/JsonPathMapCache.java ########## @@ -0,0 +1,61 @@ +/** + * 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.common.function; + +import com.jayway.jsonpath.JsonPath; +import com.jayway.jsonpath.spi.cache.Cache; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentMap; + +/** + * This cache for avoiding repeatedly compiling JSON path string when using jsonPathXXX transformations + * + * <p>The existing jay way LRUCache is very inefficient, It will cause + * a lot of unnecessary lock waits during high concurrent data ingestion, + * and LRU mechanism is inappropriate for Pinot bounded size of the + * transformation config, so we should use this simple Map cache instead + * of it. + */ +public class JsonPathMapCache implements Cache { + private final ConcurrentMap<String, JsonPath> _pathCache = new ConcurrentHashMap<>(128); + private final int _limit = 1024 * 16; + + @Override + public JsonPath get(String key) { + return _pathCache.get(key); + } + + /** + * cache JsonPath, if reached size limit, not cache it anymore. + */ + @Override + public void put(String key, JsonPath value) { + if (this.size() < _limit) { + // use putIfAbsent to handle concurrency put Review comment: Both are safe of these two puts, but there will be duplicated put when a cache misses because there is no mutex lock from get to put. I think putIfAbsent can reduce one unnecessary Map node value assignment. I think it may doesn't matter. -- 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: commits-unsubscr...@pinot.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
