netty使用ChunkedWriteHandler发送TextWebSocketFrame消息导致内存溢出-编程知识

netty使用ChunkedWriteHandler发送TextWebSocketFrame消息导致内存溢出

netty版本

		<dependency><groupId>io.netty</groupId><artifactId>netty-all</artifactId><version>4.1.50.Final</version></dependency>

此版本ChunkedWriteHandler 的write方法如下

public class ChunkedWriteHandler extends ChannelDuplexHandler {private final Queue<PendingWrite> queue = new ArrayDeque<PendingWrite>();@Overridepublic void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {queue.add(new PendingWrite(msg, promise));}
}

源码可知所有的消息都会被放置queue队列中，同时也不会触发channel高低水位设置，在大量消息堆积时导致内存无法回收OOM。堆内存分析如下：
在这里插入图片描述
解决：升级netty版本！

		<dependency><groupId>io.netty</groupId><artifactId>netty-all</artifactId><version>4.1.108.Final</version></dependency>

高版本对write方法进行了优化：

public class ChunkedWriteHandler extends ChannelDuplexHandler {private final Queue<PendingWrite> queue = new ArrayDeque<PendingWrite>();@Overridepublic void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {if (this.queueIsEmpty() && !(msg instanceof ChunkedInput)) {ctx.write(msg, promise);} else {this.allocateQueue();this.queue.add(new ChunkedWriteHandler.PendingWrite(msg, promise));}}
}