Java 在 MongoDB 中打开连接的 SocketTimeout
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SocketTimeout with opened connection in MongoDB
提问by Enrichman
I've a Java application that performs some aggregations on MongoDB, but sometimes it just hangs and throw a SocketTimeout exception. After the Exception the app will run just fine (for a bit, then it will probably raise again the exception).
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（一会儿，然后它可能会再次引发异常）。
I've just found this explanationthat seems a possible cause but I'm not sure.
我刚刚发现这个解释似乎是一个可能的原因，但我不确定。
I initalize the MongoClient and keep the connection to the DB open. I'm not sure if this could be a problem and I should just get everytime the database and then let the database to be garbage collected (and close the connection).
我初始化 MongoClient 并保持与数据库的连接打开。我不确定这是否可能是一个问题，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）。
Another approach could be ping periodically Mongo to keep the connection pool "fresh".
另一种方法可能是定期 ping Mongo 以保持连接池“新鲜”。
The client used is something like this:
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;
}
}
Is this the possible cause of the SocketTimeout?
这是 SocketTimeout 的可能原因吗？
This is the exception thrown:
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.call(FindOperation.java:487) ~[mongo-java-driver-3.2.2.jar!/:na]
at com.mongodb.operation.FindOperation.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.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.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.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
采纳答案by Enrichman
After few tries I've found out that it was a problem with the Azure's Load Balancer.
After 60s of inactivity it will disconnect any pending TCP connection.
经过几次尝试，我发现这是Azure 的负载均衡器的问题。
在 60 秒不活动后，它将断开任何挂起的 TCP 连接。
After further digging I've found this post of the MongoDB diagnostics FAQ, and I've set the tcp keepalive to 120s:
进一步挖掘后，我发现了MongoDB 诊断常见问题的这篇文章，并且我已将 tcp keepalive 设置为 120s：
sudo sysctl -w net.ipv4.tcp_keepalive_time=<value>
and I've also set the socketKeepAliveof the MongoClient to true:
我还将MongoClient的 socketKeepAlive 设置为 true：
MongoClientOptions.Builder options = MongoClientOptions.builder();
options.socketKeepAlive(true);
mongoClient = new MongoClient(mongoAddress, options.build());
After these fixes the issue seems gone!
在这些修复之后，问题似乎消失了！
回答by Prashant Agarwal
If you experience socket errors between clients and servers or between members of a sharded cluster or replica set that do not have other reasonable causes, check the TCP keepalive value (for example, the tcp_keepalive_timevalue on Linux systems). A common keepalive period is 7200 seconds (2 hours); however, different distributions and macOS may have different settings.
如果您在客户端和服务器之间或在没有其他合理原因的分片集群或副本集的成员之间遇到套接字错误，请检查 TCP keepalive 值（例如，tcp_keepalive_timeLinux 系统上的值）。常见的保活时间为 7200 秒（2 小时）；但是，不同的发行版和 macOS 可能有不同的设置。
For MongoDB, you will have better results with shorter keepalive periods, on the order of 120 seconds (two minutes).
对于 MongoDB，您将获得更短的保活期（大约 120 秒（两分钟））的更好结果。
Where you have installed mongodb you have to simply run this command on Linux
在安装 mongodb 的地方，您只需在 Linux 上运行此命令
sudo sysctl -w net.ipv4.tcp_keepalive_time=120
sudo sysctl -w net.ipv4.tcp_keepalive_time=120
Reference: Does TCP keepalive time affect MongoDB Deployments?
