RestSchemaRegistryTimeoutException: Register operation timed out

Question

I frequently get this the first time I try to register a schema after spinning up a new schema registry. After that it works fine.

Is there a way to increase time timeout?

I'm using confluentinc/cp-schema-registry:7.4.2 but I think I've seen it with the 6.x versions too.

The 500 ms timeout appears to come from kafkastore.timeout.ms and I tried to change that by passing in KAFKASTORE_TIMEOUT_MS as an env var, but the logs show it is still set to 500.

[2023-10-23 21:25:47,345] INFO Registering new schema: subject subscriptions-value, version null, id null, type null, schema size 1901 (io.confluent.kafka.schemaregistry.rest.resources.SubjectVersionsResource)
[2023-10-23 21:25:47,949] INFO Wait to catch up until the offset at 1 (io.confluent.kafka.schemaregistry.storage.KafkaStore)
[2023-10-23 21:25:47,949] INFO Reached offset at 1 (io.confluent.kafka.schemaregistry.storage.KafkaStore)
[2023-10-23 21:25:48,543] INFO [Producer clientId=producer-1] Resetting the last seen epoch of partition _schemas-0 to 0 since the associated topicId changed from null to j2jwQuFmSJqPODGtecB5Pw (org.apache.kafka.clients.Metadata)
[2023-10-23 21:25:48,548] INFO Wait to catch up until the offset at 2 (io.confluent.kafka.schemaregistry.storage.KafkaStore)
[2023-10-23 21:25:49,346] ERROR Request Failed with exception  (io.confluent.rest.exceptions.DebuggableExceptionMapper)
io.confluent.kafka.schemaregistry.rest.exceptions.RestSchemaRegistryTimeoutException: Register operation timed out
        at io.confluent.kafka.schemaregistry.rest.exceptions.Errors.operationTimeoutException(Errors.java:168)
        at io.confluent.kafka.schemaregistry.rest.resources.SubjectVersionsResource.register(SubjectVersionsResource.java:423)
...
Caused by: io.confluent.kafka.schemaregistry.exceptions.SchemaRegistryTimeoutException: Write to the Kafka store timed out while
        at io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.register(KafkaSchemaRegistry.java:743)
        at io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.registerOrForward(KafkaSchemaRegistry.java:856)
        at io.confluent.kafka.schemaregistry.rest.resources.SubjectVersionsResource.register(SubjectVersionsResource.java:412)
        ... 66 more
Caused by: io.confluent.kafka.schemaregistry.storage.exceptions.StoreTimeoutException: KafkaStoreReaderThread failed to reach target offset within the timeout interval. targetOffset: 2, offsetReached: 1, timeout(ms): 500
        at io.confluent.kafka.schemaregistry.storage.KafkaStoreReaderThread.waitUntilOffset(KafkaStoreReaderThread.java:369)
        at io.confluent.kafka.schemaregistry.storage.KafkaStore.waitUntilKafkaReaderReachesOffset(KafkaStore.java:314)
        at io.confluent.kafka.schemaregistry.storage.KafkaStore.put(KafkaStore.java:359)
        at io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.register(KafkaSchemaRegistry.java:716)
        ... 68 more