apache/pulsar · error · IllegalArgumentException

Attempting to send ${totalMessages} messages. Please do not

Error message

Attempting to send ${totalMessages} messages. Please do not send more than ${MAX_MESSAGES} messages

What it means

CmdProduce guards against accidental message floods: total messages = (inline messages + files) * numTimesProduce. If the total exceeds the CLI's MAX_MESSAGES cap, IllegalArgumentException is thrown before any client is created, protecting the broker from an accidental bulk publish.

Source

Thrown at pulsar-client-tools/src/main/java/org/apache/pulsar/client/cli/CmdProduce.java:273

        if (messages.size() == 0 && messageFileNames.size() == 0) {
            throw new CommandLine.ParameterException(commandSpec.commandLine(),
                    "Please supply message content with either --messages or --files");
        }

        if (keyValueEncodingType == null) {
            keyValueEncodingType = KEY_VALUE_ENCODING_TYPE_NOT_SET;
        } else if (!KEY_VALUE_ENCODING_TYPE_NOT_SET.equals(keyValueEncodingType)) {
            // KeyValue schemas are not yet supported by the V5-based pulsar-client.
            throw new IllegalArgumentException("KeyValue schemas (--key-value-encoding-type) are not "
                    + "supported by this version of pulsar-client; produce with a plain value schema "
                    + "(-vs bytes|string|avro:<def>|json:<def>) instead.");
        }

        int totalMessages = (messages.size() + messageFileNames.size()) * numTimesProduce;
        if (totalMessages > MAX_MESSAGES) {
            String msg = "Attempting to send " + totalMessages + " messages. Please do not send more than "
                    + MAX_MESSAGES + " messages";
            throw new IllegalArgumentException(msg);
        }

        if (this.serviceURL.startsWith("ws")) {
            return publishToWebSocket(topic);
        } else {
            return publish(topic);
        }
    }

    private int publish(String topic) {
        int numMessagesSent = 0;
        int returnCode = 0;

        if (this.disableReplication) {
            log.warn("--disable-replication has no effect on this version of pulsar-client and is ignored.");
        }

        try (PulsarClient client = clientBuilder.build()) {

View on GitHub (pinned to 820761864e)

Solutions

1. Lower --num-times-produce (-n) so totalMessages stays within the cap.
2. Reduce the number of --messages/--files entries in a single invocation and loop the command instead.
3. If you need bulk loads, use the official perf tool (pulsar-perf produce) rather than the CLI.

Example fix

// before
pulsar-client produce t -m 'a' -m 'b' -n 100000   // 200000 > MAX_MESSAGES
// after
pulsar-client produce t -m 'a' -m 'b' -n 100      // 200 <= MAX_MESSAGES

// compute the total first
TOTAL=$(( $(printf '%s\n' "$MSGS" | wc -l) * N )); [ "$TOTAL" -le 1000 ] || { echo "too many messages: $TOTAL"; exit 1; }

When it happens

Trigger: Passing many -m values or -f files combined with a large --num-times-produce (-n) so the product exceeds MAX_MESSAGES (e.g. -n 100000 with 10 messages).

Common situations: Stress-testing scripts that reuse a CLI designed for spot checks; mistyping -n (e.g. -n 1000000 instead of 1000); looping with a high multiplier to 'warm up' a topic.

Related errors

• ${paramName} cannot be bigger than <${maxValue}>!
• ${paramName} cannot be less than or equal to <0>!
• The value of ${paramName} can't be empty
• ${name} cannot be less than <${min}>!
• byte string cannot be empty

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/6d2258cf14d06c24. Report an issue: GitHub.