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Description

This error indicates that the MongoDB server has explicitly terminated a client's connection or an ongoing operation. It typically occurs when the server perceives a client as no longer active, or when an administrator manually intervenes to stop a session.

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Error Message

Client Marked Killed

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Known Causes

3 known causes

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Explicit Server Termination

A MongoDB administrator or an automated process explicitly terminated the client's operation or session using commands like `db.killOp()` or `killSessions`.

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Idle Connection Timeout

The client connection remained inactive for a period exceeding the server's configured `maxIdleTimeMS` or a cursor timeout, leading to its termination.

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Client Application Disconnect

The client application unexpectedly closed, crashed, or lost its network connection to the MongoDB server, causing the server to mark the connection as killed.

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Solutions

3 solutions available

1. Investigate and Terminate Long-Running Operations medium

Identify and kill client connections that are consuming excessive resources or have become unresponsive.

1

Connect to your MongoDB instance using the `mongosh` shell.

mongosh "mongodb://your_mongodb_host:your_mongodb_port"

2

List all active client connections and their associated operations. Look for connections with long execution times or those that appear to be stuck.

db.adminCommand({ aggregate: 1, pipeline: [ { $currentOp: {} }, { $match: { op: { $exists: true }, "$or": [ { "secs_running": { $gt: 60 } }, { "waitingForLock": true } ] } } ], cursor: {} });

3

If you identify a problematic connection (e.g., with `opid` 12345), terminate it. Be cautious as this will abruptly end the operation.

db.adminCommand({ killOp: 1, op: 12345 });

4

Monitor your application logs and MongoDB logs for any recurring patterns or specific queries that might be causing these long-running operations.

2. Adjust Network Timeout Settings medium

Configure MongoDB server and client-side network timeouts to prevent premature connection termination.

1

For MongoDB server-side timeouts, you can adjust `net.tcp.connectTimeoutMS` and `net.tcp.maxIncomingConnectionsPerHost` in your `mongod.conf` file. Restart `mongod` after changes.

net:
  tcp:
    connectTimeoutMS: 10000 # Example: 10 seconds
    maxIncomingConnectionsPerHost: 1000

2

On the client-side, consult your MongoDB driver's documentation for connection string options or configuration parameters related to connection timeouts. For example, in some drivers, you might set `connectTimeoutMS` or `socketTimeoutMS`.

// Example for Node.js driver
const { MongoClient } = require('mongodb');
const uri = "mongodb://your_mongodb_host:27017/?connectTimeoutMS=10000&socketTimeoutMS=30000";
const client = new MongoClient(uri);

3

Ensure that network infrastructure between your clients and MongoDB server (firewalls, load balancers) is not aggressively closing idle connections. Consult your network administrator if necessary.

3. Optimize Application Queries and Database Schema advanced

Improve the performance of your application's database interactions to reduce the likelihood of timeouts.

1

Use `explain()` on your application's slow queries to identify performance bottlenecks. Focus on queries with high execution times or those that don't utilize indexes effectively.

db.collection('your_collection').find({ field: 'value' }).explain()

2

Create appropriate indexes for your collections based on your query patterns. This is crucial for speeding up read operations.

db.collection('your_collection').createIndex({ field: 1 })

3

Review your database schema for potential inefficiencies. Denormalization or restructuring of data might be necessary for certain access patterns.

4

Consider implementing connection pooling on the client-side to efficiently manage database connections and reduce overhead.

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Related Errors

5 related errors

MongoDB Error 46841: Client Connection Aborted