apache/pulsar · error · ParameterException

Must specify num-partitions or num-partitions > 0 for partit

Error message

Must specify num-partitions or num-partitions > 0 for partitioned topic type.

What it means

Thrown when --enable --type partitioned is given but --default-num-partitions is missing, zero, or negative. Partitioned auto-creation requires a valid positive partition count, so the override is rejected before calling setAutoTopicCreation.

Source

Thrown at pulsar-client-tools/src/main/java/org/apache/pulsar/admin/cli/CmdNamespaces.java:663

        private Integer defaultNumPartitions = null;

        @Override
        void run() throws PulsarAdminException {
            String namespace = validateNamespace(namespaceName);
            type = type.toLowerCase().trim();

            if (enable == disable) {
                throw new ParameterException("Need to specify either --enable or --disable");
            }
            if (enable) {
                if (!TopicType.isValidTopicType(type)) {
                    throw new ParameterException("Must specify type of topic to be created. "
                            + "Possible values: (partitioned, non-partitioned)");
                }

                if (TopicType.PARTITIONED.toString().equals(type)
                        && (defaultNumPartitions == null || defaultNumPartitions <= 0)) {
                    throw new ParameterException("Must specify num-partitions or num-partitions > 0 "
                            + "for partitioned topic type.");
                }
            }
            getAdmin().namespaces().setAutoTopicCreation(namespace,
                    AutoTopicCreationOverride.builder()
                            .allowAutoTopicCreation(enable)
                            .topicType(type)
                            .defaultNumPartitions(defaultNumPartitions)
                            .build());
        }
    }

    @Command(description = "Get autoTopicCreation info for a namespace")
    private class GetAutoTopicCreation extends CliCommand {
        @Parameters(description = "tenant/namespace", arity = "1")
        private String namespaceName;

        @Override

View on GitHub (pinned to 820761864e)

Solutions

Add a positive --default-num-partitions, e.g. --default-num-partitions 4
Ensure the script computing partitions yields a number >= 1
Use --type non-partitioned instead if no partition count is desired
Verify flag name --default-num-partitions (not --num-partitions) in your CLI version

Example fix

// before
pulsar-admin namespaces set-auto-topic-creation t/ns --enable --type partitioned
// after
pulsar-admin namespaces set-auto-topic-creation t/ns --enable --type partitioned --default-num-partitions 4

Defensive patterns

Strategy: validation

Validate before calling

if [ "$TYPE" = partitioned ]; then
  [ -n "$NUM_PARTITIONS" ] && [ "$NUM_PARTITIONS" -ge 1 ] || { echo "--default-num-partitions must be >= 1 for partitioned"; exit 1; }
fi

Try / catch

try { ... } catch (ParameterException e) { /* missing/invalid partitions: add positive --default-num-partitions */ }

Prevention

Always pair --type partitioned with a positive --default-num-partitions
Validate the partitions variable is a non-empty integer >= 1
Use --type non-partitioned when no partition count applies

When it happens

Trigger: Running `set-auto-topic-creation --enable --type partitioned` without --default-num-partitions, or with a value <= 0; non-partitioned type bypasses this check entirely.

Common situations: Assuming the broker default applies; scripting where the partitions variable is empty (parses as 0/null); copying the non-partitioned invocation and switching type without adding partitions.

Related errors

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/8dc5d5a92cad957a. Report an issue: GitHub.