1.Schema.Type and org.apache.pulsar.common.schema.SchemaType value should
be the same.
2.These changes do not affect produce and are only affect consumer
subscribe behavior.
3.backward compatibility:
(1)In org.apache.pulsar.broker.service.ServerCnx#handleSubscribe.
if (schema != null && schema.getType() != SchemaType.AUTO_CONSUME) {
return topic.addSchemaIfIdleOrCheckCompatible(schema)
.thenCompose(v -> topic.subscribe(option));
} else {
return topic.subscribe(option);
}
For the older pulsar client, the schema is null if AUTO_CONSUME consumer
subscribe to the Topic.
For the new pulsar client, if AUTO_CONSUME consumer subscribe the Topic,
then schema is not null and schema.getType() = SchemaType.AUTO_CONSUME.
Both new and old pulsar clients consume the topic, will return topic.
subscribe(option).
(2)In org.apache.pulsar.broker.service.persistent.PersistentTopic
#addSchemaIfIdleOrCheckCompatible.
@Override
public CompletableFuture<Void> addSchemaIfIdleOrCheckCompatible(SchemaData
schema) {
return hasSchema().thenCompose((hasSchema) -> {
int numActiveConsumersWithoutAutoSchema = subscriptions.values().stream()
.mapToInt(subscription -> subscription.getConsumers().stream()
.filter(consumer -> consumer.getSchemaType() != SchemaType.AUTO_CONSUME)
.toList().size())
.sum();
if (hasSchema
|| (!producers.isEmpty())
|| (numActiveConsumersWithoutAutoSchema != 0)
|| (ledger.getTotalSize() != 0)) {
return checkSchemaCompatibleForConsumer(schema);
} else {
return addSchema(schema).thenCompose(schemaVersion ->
CompletableFuture.completedFuture(null));
}
});
}
Only in one case will there be a bug.
First, the old pulsar client consume the empty topic, the consumer schema
is AUTO_CONSUME, and then whether the new or old pulsar client consume(i.e.
schema is AVRO) the topic.
The broker will return the error message as IncompatibleSchemaException ("
Topic does not have a schema to check "). The bug at issue17354 is not
fixed in this case.
All the other cases will be normal.
Yunze Xu <y...@streamnative.io.invalid> 于2022年12月31日周六 20:23写道：
> Defining `AutoConsume` as -3 is somehow strange. Could you clarify if
> backward compatibility is guaranteed? i.e. if the new Pulsar client
> uploaded the AUTO_CONSUME schema to the broker, can the old Pulsar
> clients produce or consume the same topic anymore?
>
> Thanks,
> Yunze
>
> On Fri, Dec 30, 2022 at 11:32 PM 思楠刘 <liusinan1...@gmail.com> wrote:
> >
> > Hi all,
> >
> > I made a PIP to discuss: https://github.com/apache/pulsar/issues/19113.
> >
> > Thanks,
> > Sinan
>
