arina-ielchiieva commented on a change in pull request #2000: DRILL-7607: Support dynamic credit based flow control URL: https://github.com/apache/drill/pull/2000#discussion_r386879614
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/rpc/DynamicSemaphore.java ########## @@ -0,0 +1,84 @@ +/* + * 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.drill.exec.rpc; + +import java.util.concurrent.Semaphore; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.locks.ReentrantLock; + +/** + * Dynamic credit based flow control: + * The sender initially sends batch to the sender by the initial static credit (3). + * The receiver will calculate a runtime credit value while sampling some received batches. The runtime + * generated credit value will be sent to the receiver as an ack value. The sender will change to the + * runtime generated credit value while received the ack credit value. + * + * The ack credit value has three type numeric value with different meaning: + * 0 : meaning no explicit credit value to the sender, just keep the initial static credit based fc. + * -1: meaning the receiver has gone to wrong to solve the query. + * value greater than 0: meaning a runtime generated credit value for the sender to change to. + */ +public class DynamicSemaphore { + + private static int INITIAL_STATIC_CREDIT = 3; + private Semaphore semaphore = new Semaphore(INITIAL_STATIC_CREDIT); + private AtomicBoolean changed = new AtomicBoolean(false); + private ReentrantLock lock = new ReentrantLock(); Review comment: final? ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services
