apache/pulsar · error · RestException

Desired partitions %s can't be greater than the maximum part

Error message

Desired partitions %s can't be greater than the maximum partitions per topic %s.

What it means

internalUpdatePartitionedTopicAsync pre-check failure (422): the requested partition count exceeds the cluster's maximum allowed partitions per topic, so the update is rejected to prevent creating more partitions than the broker configuration permits.

Source

Thrown at pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/PersistentTopicsBase.java:394

                                                                                   boolean updateLocal,
                                                                                   boolean force) {
        PulsarService pulsarService = pulsar();
        return pulsarService.getBrokerService().fetchPartitionedTopicMetadataAsync(topicName)
            .thenCompose(partitionedTopicMetadata -> {
                int currentMetadataPartitions = partitionedTopicMetadata.partitions;
                if (currentMetadataPartitions <= 0) {
                    throw new RestException(Status.CONFLICT /* Unprocessable entity*/,
                            String.format("Topic %s is not the partitioned topic.", topicName));
                }
                if (expectPartitions < currentMetadataPartitions) {
                    throw new RestException(422 /* Unprocessable entity*/,
                            String.format("Desired partitions %s can't be less than the current partitions %s.",
                                    expectPartitions, currentMetadataPartitions));
                }
                int brokerMaximumPartitionsPerTopic = pulsarService.getConfiguration()
                        .getMaxNumPartitionsPerPartitionedTopic();
                if (brokerMaximumPartitionsPerTopic > 0 && expectPartitions > brokerMaximumPartitionsPerTopic) {
                    throw new RestException(422 /* Unprocessable entity*/,
                            String.format("Desired partitions %s can't be greater than the maximum partitions per"
                                            + " topic %s.",
                                    expectPartitions, brokerMaximumPartitionsPerTopic));
                }
                final PulsarAdmin admin;
                try {
                    admin = pulsarService.getAdminClient();
                } catch (PulsarServerException ex) {
                    throw new RestException(Status.INTERNAL_SERVER_ERROR, Throwables.getRootCause(ex));
                }
                final CompletableFuture<Void> checkFuture;
                if (!force) {
                    checkFuture = admin.topics().getListAsync(topicName.getNamespace(), topicName.getDomain())
                            .thenAccept(topics -> {
                                final List<TopicName> existingPartitions = topics.stream()
                                        .map(TopicName::get)
                                        .filter(candidateTopicName -> candidateTopicName.getPartitionedTopicName()
                                                .equals(topicName.getPartitionedTopicName()))

View on GitHub (pinned to 820761864e)

Solutions

1. Request a count within maxPartitionsPerTopic
2. Ask the admin to raise maxPartitionsPerTopic if a larger topic is genuinely needed

When it happens

Trigger: Thrown at pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/PersistentTopicsBase.java:394 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/221bfa914c0f108d. Report an issue: GitHub.