apache/pulsar · error · SerializationException

Failed at fetching schema info for <SchemaUtils.getStringSch

Error message

Failed at fetching schema info for <SchemaUtils.getStringSchemaVersion(schemaVersion)>

What it means

getSchemaInfoByVersion wraps ExecutionException from the async schema lookup and rethrows it as SerializationException 'Failed at fetching schema info for <version>' with the original cause. This means the schema info provider failed to return the schema for that version (broker error, missing schema, permission issue).

Source

Thrown at pulsar-client/src/main/java/org/apache/pulsar/client/impl/schema/reader/AbstractMultiVersionReader.java:130

     * @param schemaVersion the provided schema version
     * @return the schema reader for decoding messages encoded by the provided schema version.
     */
    protected abstract SchemaReader<T> loadReader(BytesSchemaVersion schemaVersion);

    /**
     * TODO: think about how to make this async.
     */
    protected SchemaInfo getSchemaInfoByVersion(byte[] schemaVersion) {
        try {
            return schemaInfoProvider.getSchemaByVersion(schemaVersion).get();
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            throw new SerializationException(
                    "Interrupted at fetching schema info for " + SchemaUtils.getStringSchemaVersion(schemaVersion),
                    e
            );
        } catch (ExecutionException e) {
            throw new SerializationException(
                    "Failed at fetching schema info for " + SchemaUtils.getStringSchemaVersion(schemaVersion),
                    e.getCause()
            );
        }
    }
}

View on GitHub (pinned to 820761864e)

Solutions

1. Look at e.getCause() in the SerializationException for the real broker/registry error
2. Verify the schema version exists: pulsar-admin schemas get <topic>
3. Re-upload the missing schema or configure a reader schema compatible with old messages
4. Check client permissions for schema read operations on the topic
5. Ensure broker connectivity and retry after transient failures

Example fix

// before
SchemaInfo info = reader.getSchemaInfoByVersion(version); // SerializationException
// after
try {
    SchemaInfo info = reader.getSchemaInfoByVersion(version);
} catch (SerializationException e) {
    LOGGER.warn("Schema fetch failed for version " + version, e.getCause());
    // re-upload schema or attach compatible reader schema
}

// verify version exists before decode:
// pulsar-admin schemas get <topic> / broker HTTP GET /admin/v2/schemas/<topic>/versions/<id>

null

try {
    SchemaInfo info = reader.getSchemaInfoByVersion(version);
} catch (SerializationException e) {
    Throwable cause = e.getCause();
    log.error("Schema fetch failed for version {} cause {}", version, cause);
    // re-upload schema or use compatible reader schema, then retry
}

When it happens

Trigger: Calling getSchemaInfoByVersion/read when the CompletableFuture from schemaInfoProvider.getSchemaByVersion completes exceptionally — HTTP 404 for missing schema version, broker errors, auth failures.

Common situations: Consuming messages whose schema version was deleted from the topic; broker schema registry unavailable; client lacks schema read permission; schema version bytes corrupted; topic recreated without the old schema.

Related errors

• Can't get generic schema for topic <schemaInfoProvider.getTo
• Can not enable for all producers but denies for replicators,
• Failed to add schema to an active topic with empty(BYTES) sc
• External schema is not compatible with the other schema type
• Only allowed to set schemaInfoForReplicator for a replicated

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/8313ee4634467fd6. Report an issue: GitHub.