apache/pulsar · error · RestException

This topic already exists

Error message

This topic already exists

What it means

internalCreateNonPartitionedTopicAsync detected that the topic being created already exists on the broker, so creation is refused with 409 Conflict rather than overwriting the existing topic's metadata.

Source

Thrown at pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/PersistentTopicsBase.java:351

                    resumeAsyncResponseExceptionally(asyncResponse, realCause);
                    return null;
                });
    }

    protected CompletableFuture<Void> internalCreateNonPartitionedTopicAsync(boolean authoritative,
                                                     Map<String, String> properties) {
        return validateNonPartitionTopicNameAsync(topicName.getLocalName())
                .thenCompose(__ -> validateGlobalNamespaceOwnershipAsync(namespaceName))
                .thenCompose(__ -> validateTopicOwnershipAsync(topicName, authoritative))
           .thenCompose(__ -> validateNamespaceOperationAsync(topicName.getNamespaceObject(),
                   NamespaceOperation.CREATE_TOPIC))
           .thenCompose(__ -> getPartitionedTopicMetadataAsync(topicName, false, false))
           .thenAccept(partitionMetadata -> {
               if (partitionMetadata.partitions > 0) {
                   log.warn()
                           .attr("exists", topicName)
                           .log("Partitioned topic with the same name already exists");
                   throw new RestException(Status.CONFLICT, "This topic already exists");
               }
           })
           .thenCompose(__ -> pulsar().getBrokerService().getTopicIfExists(topicName.toString()))
           .thenCompose(existedTopic -> {
               if (existedTopic.isPresent()) {
                   log.warn().attr("topic", topicName).log("Topic already exists");
                   throw new RestException(Status.CONFLICT, "This topic already exists");
               }
               return pulsar().getBrokerService().getTopic(topicName.toString(), true, properties);
           })
           .thenAccept(__ -> log.info()
                   .attr("topic", topicName)
                   .log("Successfully created non-partitioned topic"));
    }

    /**
     * It updates number of partitions of an existing partitioned topic. It requires partitioned-topic to
     * already exist and number of new partitions must be greater than existing number of partitions. Decrementing

View on GitHub (pinned to 820761864e)

Solutions

1. Use the existing topic instead of creating it
2. Pass the appropriate create-or-continue semantics if supported by the client

When it happens

Trigger: Thrown at pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/PersistentTopicsBase.java:351 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/42a978ea10976b0e. Report an issue: GitHub.