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Troubleshooting overview

If you experience any issues with FerretDB, this troubleshooting guide will help you resolve them.

Connectivity issues​

Do you have trouble setting up or connecting to FerretDB? Find solutions to common connectivity issues below.

Error initializing PostgreSQL with the DocumentDB extension in Docker​

If you get an error when initializing PostgreSQL with the DocumentDB extension in Docker, it may be due to an existing PostgreSQL data directory or volume. This error occurs because the previous PostgreSQL data directory was created without the DocumentDB extension.

Log error may look like this:

schema "documentdb_api" does not exist

To resolve this issue, delete the existing PostgreSQL data directory if unused or change the data directory path in your Docker setup. For example, if the path to the data directory of your PostgreSQL with DocumentDB extension instance is ./data, change it to ./postgres-data. You may need to export or migrate your data to the new PostgreSQL data directory. Follow our migration guide for more details.

For more details on setting up PostgreSQL with the DocumentDB extension in Docker, see the Docker installation guide.

Authentication error when connecting to FerretDB​

If you get an error when connecting to FerretDB with the PLAIN authentication mechanism (e.g. mongodb://username:password@127.0.0.1:27017/ferretdb?authMechanism=PLAIN), it is because PLAIN authentication is no longer supported in FerretDB v2.x.

Log error may look like this:

Error: Received authentication for mechanism PLAIN which is not enabled.

Note that FerretDB v2.x uses the SCRAM-SHA-256 authentication mechanism, and authentication is enabled by default. To resolve this issue, connect to FerretDB without specifying the PLAIN mechanism in the connection string (e.g. mongodb://username:password@127.0.0.1:27017/).

Learn more about FerretDB authentication.

Compatibility issues​

For any compatibility issues or concerns, read our pre-migration testing guide. The guide will help you identify any potential compatibility issues before migrating your data to FerretDB.

Performance issues​

If you experience performance issues or have concerns about your FerretDB setup, debugging and observability tools can help. Our observability guide provides insights into logging, OpenTelemetry traces, debug handlers, metrics, and health probes, which can help diagnose these issues and optimize performance effectively.

Other issues​

If your issues persist or you encounter other problems, please check your logs for details and share them with us on any of our community channels to get help resolving them.