Error
Error Code:
206
MongoDB Error 206: No Such Session
Description
This error indicates that a client attempted to use a session ID that is no longer recognized by the MongoDB server. This typically occurs when a session has expired, been invalidated, or was never properly established.
Error Message
No Such Session
Known Causes
4 known causesSession Expiration
MongoDB sessions have a defined timeout. If a client attempts to use a session ID after its expiration, the server will no longer recognize it.
Invalid Session ID Provided
The client application provided a session ID that does not correspond to any active or previously valid session on the MongoDB server, possibly due to client-side data corruption or an incorrect ID.
Server Restart or Failover
If a MongoDB server instance handling a session restarts or a replica set failover occurs, existing sessions on the affected server may become invalid.
Client-Side Session Mismanagement
The client application might be incorrectly storing, retrieving, or attempting to reuse session IDs that are no longer valid or were never properly initiated.
Solutions
4 solutions available1. Restart the Application or Client Connecting to MongoDB easy
The most common cause is a stale connection from the application holding an invalid session ID.
1
Identify the application or service that is making the MongoDB requests.
2
Gracefully restart that application or service. This will typically force it to establish a new connection and a new session.
Example for a Node.js application using PM2:
bash
pm2 restart <your_app_name>
Example for a Python application using systemd:
bash
sudo systemctl restart <your_service_name>
2. Verify and Refresh MongoDB Driver/Client Configuration medium
Ensure your MongoDB driver or client library is up-to-date and correctly configured, as outdated versions or misconfigurations can lead to session issues.
1
Check the version of the MongoDB driver or client library used by your application.
For Node.js (npm):
bash
npm list mongodb
For Python (pip):
bash
pip freeze | grep pymongo
2
If the driver is outdated, update it to the latest stable version.
For Node.js (npm):
bash
npm install mongodb@latest
For Python (pip):
bash
pip install --upgrade pymongo
3
Review your application's MongoDB connection string and configuration. Ensure it's correctly pointing to your MongoDB instance and any necessary authentication details are accurate.
Example Node.js connection string:
javascript
const uri = "mongodb://username:password@host:port/database?retryWrites=true&w=majority";
const client = new MongoClient(uri);
4
After updating or reconfiguring, restart your application.
3. Investigate Potential Network Intermittency or Firewall Issues medium
Transient network problems or aggressive firewalls can disrupt ongoing MongoDB sessions, leading to this error.
1
Check for any recent network changes or known network issues between your application server(s) and the MongoDB server(s).
2
If using firewalls, ensure that the necessary ports (default 27017) are open and that there are no rules that might be prematurely closing connections.
Example using iptables (Linux):
bash
sudo iptables -L -n -v
Look for rules that might be related to the MongoDB port and check for connection tracking or timeout settings.3
Monitor network traffic for dropped packets or high latency between the client and the MongoDB server.
4
If network issues are suspected, work with your network administrator to resolve them. Consider implementing connection pooling with appropriate timeouts in your application to mitigate the impact of brief network disruptions.
4. Restart the MongoDB Server (Use with Caution) advanced
In rare cases, the MongoDB server itself might be in a state where it's not properly managing sessions. A restart can resolve this but may cause a brief service interruption.
1
Ensure you have a maintenance window or can tolerate a brief downtime.
2
Connect to the server hosting your MongoDB instance.
3
Stop the MongoDB service. The command varies depending on your operating system and installation method.
For systems using systemd (common on modern Linux):
bash
sudo systemctl stop mongod
For systems using init.d (older Linux):
bash
sudo service mongod stop
For Windows:
Open Services (services.msc), find the MongoDB service, and click 'Stop'.4
Wait for the service to fully stop. You can check the status if available.
For systems using systemd:
bash
sudo systemctl status mongod
5
Start the MongoDB service.
For systems using systemd:
bash
sudo systemctl start mongod
For systems using init.d:
bash
sudo service mongod start
For Windows:
In Services, find the MongoDB service and click 'Start'.6
Monitor the MongoDB logs for any errors during startup.