ApsaraMQ for Kafka:Why message accumulation for a Group shows 0 or is empty

Consumer offset not committed or expired

This is the most common cause. The system calculates message accumulation as the difference between the latest offset and the consumer offset. If no consumer offset exists, the system cannot compute this value and displays 0 or leaves the field empty.

This happens in two scenarios:

• The consumer never committed an offset. If enable.auto.commit is set to false and no manual commit call (commitSync() or commitAsync()) is made, no consumer offset is stored. Without a baseline offset, the system cannot calculate message accumulation. By default, enable.auto.commit is true, and offsets are committed automatically at the interval specified by auto.commit.interval.ms (default: 5 seconds). If you disabled auto-commit, you must commit offsets explicitly in your consumer code.

• The consumer offset expired. Consumer offsets are retained for a limited period controlled by the offsets.retention.minutes broker configuration. If a Group stops consuming and the retention period elapses, the stored offsets are deleted. When offsets expire, the consumer group data is cleaned up, and lag cannot be calculated.

How to verify:

1. In the ApsaraMQ for Kafka console, go to Groups and check whether the Group has any committed consumer offset.

2. If the consumer offset column is empty for all partitions, the offsets were either never committed or have expired.

You can also use the kafka-consumer-groups CLI tool to inspect the Group. The output looks similar to the following:

TOPIC          PARTITION  CURRENT-OFFSET  LOG-END-OFFSET  LAG  CONSUMER-ID       HOST         CLIENT-ID
my-topic       0          -               4               -    consumer-1-...    /127.0.0.1   consumer-1
my-topic       1          -               3               -    consumer-1-...    /127.0.0.1   consumer-1

A - in the CURRENT-OFFSET and LAG columns indicates that no consumer offset is committed for that partition.

How to fix:

• If auto-commit is disabled, add explicit offset commits to your consumer code or set enable.auto.commit to true.

• If offsets expired because the consumer was idle too long, restart the consumer. New offsets are committed once the consumer begins processing messages.

Consumer offset manually reset to 0

If you manually reset the consumer offset for a partition to 0, the message accumulation value may display incorrectly. After a reset, the system recalculates message accumulation based on the new offset. Depending on timing and consumer state, the displayed value may temporarily show 0 or appear empty before the consumer resumes and commits updated offsets.

How to verify:

Check the consumer offset for each partition in the Group's consumption status. If any partition shows a consumer offset of 0 while the latest offset is much larger, a manual reset likely occurred. The CLI output looks similar to the following:

TOPIC          PARTITION  CURRENT-OFFSET  LOG-END-OFFSET  LAG  CONSUMER-ID       HOST         CLIENT-ID
my-topic       0          0               15000           15000 consumer-1-...   /127.0.0.1   consumer-1

A CURRENT-OFFSET of 0 with a large LOG-END-OFFSET indicates a recent offset reset.

How to fix:

Allow the consumer to resume processing. As the consumer commits updated offsets, the message accumulation value corrects itself.

Consumer offset equals the latest offset

This is normal behavior. When the consumer offset matches the latest offset, message accumulation is 0 because the consumer has fully caught up with all produced messages.

How to verify:

Compare the consumer offset and latest offset for each partition. If they match across all partitions, the Group is fully caught up and 0 is the correct value. The CLI output looks similar to the following:

TOPIC          PARTITION  CURRENT-OFFSET  LOG-END-OFFSET  LAG  CONSUMER-ID       HOST         CLIENT-ID
my-topic       0          150             150             0    consumer-1-...    /127.0.0.1   consumer-1
my-topic       1          200             200             0    consumer-2-...    /127.0.0.1   consumer-2

Consumer Group states

When troubleshooting message accumulation issues, check the consumer Group state. The state affects whether lag data is available.

Related configuration parameters