How to check previous schemas registered in Registry?
I'm trying to register but I am getting "Schema being registered is incompatible with an earlier schema for subject" exception
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1Please provide enough code so others can better understand or reproduce the problem. – Community Jul 26 '22 at 14:31
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Compatibility checks will only operate against the latest stored subject version
https://docs.confluent.io/platform/current/schema-registry/develop/api.html#sr-api-compatibility
You'd check the schemas using the subject and version number(s)
Neither will tell you "why" it is incompatible, but Avro has clear documentation on that, for example
OneCricketeer
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Is there a way to find out why the schema fails compatibility check when I receive `"is_compatible": "false"` when calling `/compatibility/subjects/{schema_name}/versions/{last_version}` ? – d56 Jul 27 '22 at 16:20
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As answered, the API doesn't return this information. You will need to read the relevant documentation for the serialization format you are using. Or you can create a new question here and upload both of your schemas. – OneCricketeer Jul 27 '22 at 17:40
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You can try the following
- Command to get all versions of the previously registered schemas
SchemaRegistryURL/subjects/topicname-value/versions
- Command to get a specific version of all previously registered Schemas
SchemaRegistryURL/subjects/topicname-value/versions/version
Schema Compatibility option might not set it correctly, in which case you can reset the Compatibility using the following command and try re-registering your schema.
curl -k -X PUT -H "Content-Type:application/vnd.schemaregistry.v1+json" --data '{"compatibility": "NONE"}' SchemaRegistryURL/config/topic-value
From https://docs.confluent.io/platform/current/schema-registry/avro.html#summary
Compatibility
Transitive compatibility checking is important once you have more than two versions of a schema for a given subject. If compatibility is configured as transitive, then it checks compatibility of a new schema against all previously registered schemas; otherwise, it checks compatibility of a new schema only against the latest schema.
For example, if there are three schemas for a subject that change in order X-2, X-1, and X then:
transitive: ensures compatibility between X-2 <==> X-1 and X-1 <==> X and X-2 <==> X
non-transitive: ensures compatibility between X-2 <==> X-1 and X-1 <==> X, but not necessarily X-2 <==> X
The Confluent Schema Registry default compatibility type BACKWARD is non-transitive, which means that it’s not BACKWARD_TRANSITIVE. As a result, new schemas are checked for compatibility only against the latest schema.
BACKWARD: (default) consumers using X-2 can read data written by producers X-1
BACKWARD_TRANSITIVE: consumers using X-2 can read data written by producers using X-1, and X
FORWARD: consumers using X-1 can read data written by producers using X-2
FORWARD_TRANSITIVE: consumers using X-1 or X can read data written by producers using X-2
FULL: the new schema is forward and backward compatible with the latest registered schema
FULL_TRANSITIVE: the new schema is forward and backward compatible with all previously registered schemas
NONE: schema compatibility checks are disabled
OneCricketeer
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ChristDist
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It is explained in Schema Evolution.
The Confluent Schema Registry default compatibility type is BACKWARD so you cannot add more fields or change datatype.
You need to change the compatibility.
Luis Estrada
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