Schema Mismatch

Issue ^^^^^

A cqlsh operation failed with schema version mismatch detected error message.

For example

.. code-block:: shell

OperationTimedOut: errors={'10.1.1.54': 'Request timed out while waiting for schema agreement. See Session.execute_async and Cluster.max_schema_agreement_wait.'}, last_host=10.1.1.54 Warning: schema version mismatch detected; check the schema versions of your nodes in system.local and system.peers.

Problem ^^^^^^^

One or more ScyllaDB nodes have a schema mismatch.

How to Verify ^^^^^^^^^^^^^

Run :doc:nodetool describecluster </operating-scylla/nodetool-commands/describecluster/>

In the following example, one node, 172.17.0.3 has a different schema than the other two nodes. As a temporary state, this is fine, but if this state persists, it will fail CQL operations.

.. code-block:: cql

Cluster Information: Name: Test Cluster Snitch: org.apache.cassandra.locator.SimpleSnitch DynamicEndPointSnitch: disabled Partitioner: org.apache.cassandra.dht.Murmur3Partitioner Schema versions: f04247d2-e2a6-3785-9fb8-8a57c7bdb25c: [172.17.0.1, 172.17.0.2] b1c9af1d-4f90-39fb-a869-95eeb3da96af: [172.17.0.3]

Solution ^^^^^^^^

Wait for five minutes and run nodetool describecluster to verify that the schema is synced.
If there is still a mismatch error message execute a rolling restart_.
Verify schema is synced

For example:

.. code-block:: cql

Cluster Information: Name: Test Cluster Snitch: org.apache.cassandra.locator.SimpleSnitch DynamicEndPointSnitch: disabled Partitioner: org.apache.cassandra.dht.Murmur3Partitioner Schema versions: 1fd57629-6bae-3f23-97d1-ffa4208cc372: [172.17.0.1, 172.17.0.2, 172.17.0.3]

.. _rolling restart: /operating-scylla/procedures/config-change/rolling_restart/