java spymemcached bug?
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MemcachedClient memcachedClient = new MemcachedClient(new InetSocketAddress("192.168.1.111", 11211)); long time = System.currentTimeMillis(); Future<Boolean> future = memcachedClient.set("xwagnquan", 3600, time);?
??????? 程序启动后，用CurrPorts( http://www.nirsoft.net/utils/cports.html ,windows下一个小工具,用于查看和管理tcp/udp的连接状况,比netstat 方便)查看客户端的连接状况, 如下图:
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??????? 很明显 ，进程编号为6032,本地端口为24550，远程端口为192.168.1.111：11211的是我与server建立的连接,使用24550语192.168.1.111server通讯。
?????? 问题1，剩下的那几个java通道分别连接到111的其他端口，在java nio中这些通道是做什么用的,有什么意义?在基于mina的通讯程序中，我与server建立一个连接后，只发现一个类似6032这的通道!
?????? 接着，我关掉一个与24550有关的java通道,发现spymemcache 后台疯狂的打出
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has a ready op, handling IO
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has 1, interested in 0
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has a ready op, handling IO
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has 1, interested in 0
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has a ready op, handling IO
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has 1, interested in 0
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has a ready op, handling IO
2009-04-23 17:40:29.171 INFO net.spy.memcached.MemcachedConnection:? sun.nio.ch.SelectionKeyImpl@1884174 has 1, interested in 0
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????? 这类信息！导致cpu使用很高,后更跟踪sypmemcached源代码发现在MemcachedConnection这个类中的handleIO（）方法中有如下逻辑，
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if(selectedKeys.isEmpty() && !shutDown) {getLogger().debug("No selectors ready, interrupted: "+ Thread.interrupted());if(++emptySelects > DOUBLE_CHECK_EMPTY) {for (SelectionKey sk : selector.keys()) {getLogger().info("%s has %s, interested in %s",sk, sk.readyOps(), sk.interestOps());if(sk.readyOps() != 0) {getLogger().info("%s has a ready op, handling IO", sk);handleIO(sk);} else {lostConnection((MemcachedNode)sk.attachment());}}assert emptySelects < EXCESSIVE_EMPTY: "Too many empty selects";}?????
???? 这块逻辑我没看清楚他的作用！
?????以上暴漏出一个严重的问题，如果一个java通道被外在因素强制关闭，会导致以上逻辑反复的执行，导致cpu使用率彪到极限,且一直处于最高峰!
???? 是不是这个框架有问题呢??以后选择memcached java client 是不是要注意一下呢？?
???? 请熟悉spymemcached 和java socket 的哥们帮忙解释一下，谢谢!
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