When migrating schema registry data from a Confluent Cluster to Redpanda using the migration tool, customers may encounter a 500 error in the Console UI with the message "schema registry request failed: 422 - parse error at offset 39". This issue occurs because Redpanda Schema Registry only supports metadata with a null value, while the imported data contains non-null metadata.

Symptoms

• 500 errors in the Console UI
• 422 Unprocessable Entity errors when querying the /subjects endpoint
• "parse error at offset 39" when using rpk registry schema list

Solution

To resolve this issue, follow these steps:

1. Delete the existing _schemas topic
2. Recreate the _schemas topic with proper configurations
3. Re-import the schema data after removing the metadata

Detailed Steps:

1. Remove _schemas from the kafka_nodelete_topics configuration:

   rpk cluster config set kafka_nodelete_topics '["_redpanda.audit_log", "__consumer_offsets"]'

2. Delete the _schemas topic:

   rpk topic delete _schemas

3. Recreate the _schemas topic with the correct configurations:

   rpk topic create _schemas -c cleanup.policy=compact -c compression.type=none -c initial.retention.local.target.bytes=-1 -c initial.retention.local.target.ms=-1 -c retention.bytes=-1 -c retention.local.target.bytes=-1 -c retention.local.target.ms=-1 -c retention.ms=-1 ${rpkauth}

4. Add _schemas back to kafka_nodelete_topics:

   rpk cluster config set kafka_nodelete_topics '["_redpanda.audit_log", "__consumer_offsets", "_schemas"]'

5. Re-import the schema data after removing the metadata from the exported data.

If you need additional help please reach out to the Support Team.