siddharthteotia commented on code in PR #11496: URL: https://github.com/apache/pinot/pull/11496#discussion_r1321100718
########## pinot-core/src/main/java/org/apache/pinot/core/transport/DirectOOMHandler.java: ########## @@ -0,0 +1,100 @@ +/** + * 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.transport; + +import io.netty.channel.Channel; +import io.netty.channel.ChannelHandlerContext; +import io.netty.channel.ChannelInboundHandlerAdapter; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.atomic.AtomicBoolean; +import org.apache.pinot.spi.exception.QueryCancelledException; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +// Handling netty direct memory OOM. In this case there is a great chance that multiple channels are receiving +// large data tables from servers concurrently. We want to close all channels to servers to proactively release +// the direct memory, because the execution of netty threads can deadlock in allocating direct memory, in which case Review Comment: I wonder why do mention deadlock. From our internal RCA for the issue we saw in production, I don't think we observed a deadlock. I understand you are probably referring to Netty thread trying repeated memory allocation where even after observing initial failure, RPC threads repeatedly keep trying allocating memory which internally calls into System.GC and which keeps failing because we are holding onto direct memory references. So I feel `deadlock` here may be a slightly misleading ? -- 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
