在 MongoDB 中打开连接的 SocketTimeout

Question

我有一个在 MongoDB 上执行一些聚合的 Java 应用程序，但有时它只是挂起并抛出 SocketTimeout 异常。在异常之后，应用程序将运行得很好（有一点，然后它可能会再次引发异常）。

我刚刚发现 这个解释 似乎是一个可能的原因，但我不确定。

我初始化 MongoClient 并保持与数据库的连接打开。我不确定这是否是个问题，我应该每次都获取数据库，然后让数据库被垃圾收集（并关闭连接）。

另一种方法是定期 ping Mongo 以保持连接池“新鲜”。

使用的客户端是这样的：

 public class DbClient {

    private static MongoClient mongoClient;
    private static MongoDatabase db;

    private DbClient() {}

    public static void init() throws Exception {
        mongoClient = new MongoClient();
    }

    public static MongoDatabase getDB() {
        if(mongoClient == null)
            throw new IllegalStateException("Client not initialized!");

        if(db == null) {
            db = mongoClient.getDatabase("my_db");
        }
        return db;
    }
}

这是 SocketTimeout 的可能原因吗？

这是抛出的异常：

 09:20:45.742 [qtp605535417-46] INFO  org.mongodb.driver.connection - Closed connection [connectionId{localValue:16, serverValue:6562}] to myapp.com:27017 because there was a socket exception raised by this connection.
09:20:45.743 [qtp605535417-46] ERROR myapp.service.Api - Error processing request
com.mongodb.MongoSocketReadTimeoutException: Timeout while receiving message
    at com.mongodb.connection.InternalStreamConnection.translateReadException(InternalStreamConnection.java:474) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.InternalStreamConnection.receiveMessage(InternalStreamConnection.java:225) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.UsageTrackingInternalConnection.receiveMessage(UsageTrackingInternalConnection.java:102) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.DefaultConnectionPool$PooledConnection.receiveMessage(DefaultConnectionPool.java:435) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.CommandProtocol.execute(CommandProtocol.java:112) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.DefaultServer$DefaultServerProtocolExecutor.execute(DefaultServer.java:159) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.DefaultServerConnection.executeProtocol(DefaultServerConnection.java:286) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.DefaultServerConnection.command(DefaultServerConnection.java:173) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:215) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:206) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:112) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.FindOperation$1.call(FindOperation.java:487) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.FindOperation$1.call(FindOperation.java:482) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:239) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:212) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.FindOperation.execute(FindOperation.java:482) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.operation.FindOperation.execute(FindOperation.java:79) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.Mongo.execute(Mongo.java:772) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.Mongo$2.execute(Mongo.java:759) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.OperationIterable.iterator(OperationIterable.java:47) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.FindIterableImpl.iterator(FindIterableImpl.java:143) ~[mongo-java-driver-3.2.2.jar!/:na]
    at myapp.common.db.service.dao.AnalysisMongoImpl.getAnalysis(AnalysisMongoImpl.java:66) ~[common-0.2.0-SNAPSHOT.jar!/:na]
    at myapp.common.db.service.AnalysisServiceImpl.getAnalysis(AnalysisServiceImpl.java:31) ~[common-0.2.0-SNAPSHOT.jar!/:na]
    at myapp.aggregator.service.Api$1.handle(Api.java:88) ~[aggregator-0.2.0-SNAPSHOT.jar!/:na]
    at spark.webserver.MatcherFilter.doFilter(MatcherFilter.java:139) [spark-core-1.1.1.jar!/:na]
    at spark.webserver.JettyHandler.doHandle(JettyHandler.java:54) [spark-core-1.1.1.jar!/:na]
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:179) [jetty-server-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:136) [jetty-server-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97) [jetty-server-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.server.Server.handle(Server.java:451) [jetty-server-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.server.HttpChannel.run(HttpChannel.java:252) [jetty-server-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:266) [jetty-server-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.run(AbstractConnection.java:240) [jetty-io-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:596) [jetty-util-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:527) [jetty-util-9.0.2.v20130417.jar!/:9.0.2.v20130417]
    at java.lang.Thread.run(Thread.java:745) [na:1.7.0_95]
Caused by: java.net.SocketTimeoutException: Read timed out
    at java.net.SocketInputStream.socketRead0(Native Method) ~[na:1.7.0_95]
    at java.net.SocketInputStream.read(SocketInputStream.java:152) ~[na:1.7.0_95]
    at java.net.SocketInputStream.read(SocketInputStream.java:122) ~[na:1.7.0_95]
    at com.mongodb.connection.SocketStream.read(SocketStream.java:85) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.InternalStreamConnection.receiveResponseBuffers(InternalStreamConnection.java:491) ~[mongo-java-driver-3.2.2.jar!/:na]
    at com.mongodb.connection.InternalStreamConnection.receiveMessage(InternalStreamConnection.java:221) ~[mongo-java-driver-3.2.2.jar!/:na]
    ... 34 common frames omitted

原文由 Enrichman 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

经过几次尝试，我发现这是 Azure 的 Load Balancer 的问题。

在 60 秒不活动后，它将断开任何挂起的 TCP 连接。

进一步挖掘后，我发现了这篇 MongoDB 诊断常见问题解答 的帖子，并且我将 tcp keepalive 设置为 120s：

 sudo sysctl -w net.ipv4.tcp_keepalive_time=<value>

并且我还将 MongoClient 的 socketKeepAlive 设置为 true：

 MongoClientOptions.Builder options = MongoClientOptions.builder();
options.socketKeepAlive(true);
mongoClient = new MongoClient(mongoAddress, options.build());

在这些修复之后，问题似乎消失了！

原文由 Enrichman 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

如果您在客户端和服务器之间或分片集群或副本集的成员之间遇到没有其他合理原因的套接字错误，请检查 TCP keepalive 值（例如， tcp_keepalive_time Linux 系统上的值）。一个常见的keepalive周期是7200秒（2小时）；但是，不同的发行版和 macOS 可能有不同的设置。

对于 MongoDB，保持活动时间较短（大约 120 秒（两分钟））会获得更好的结果。

在安装了 mongodb 的地方，您只需在 Linux 上运行此命令

sudo sysctl -w net.ipv4.tcp_keepalive_time=120

参考： Does TCP keepalive time affect MongoDB Deployments?

原文由 Prashant Agarwal 发布，翻译遵循 CC BY-SA 4.0 许可协议