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ClickHouse/docs/en/operations/system-tables/kafka_consumers.md
Ilya Golshtein 40fd53c3e3 system_kafka_consumers: style check
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slug
/en/operations/system-tables/kafka_consumers

kafka_consumers

Contains information about Kafka consumers. Applicable for Kafka table engine (native ClickHouse integration)

Columns:

  • database (String) - database of the table with Kafka Engine.
  • table (String) - name of the table with Kafka Engine.
  • consumer_id (String) - Kafka consumer identifier. Note, that a table can have many consumers. Specified by kafka_num_consumers parameter.
  • assignments.topic (Array(String)) - Kafka topic.
  • assignments.partition_id (Array(Int32)) - Kafka partition id. Note, that only one consumer can be assigned to a partition.
  • assignments.current_offset (Array(Int64)) - current offset.
  • last_exception_time, (DateTime) - timestamp when the most recent exception was generated.
  • last_exception, (String) - text of the most recent exception.
  • last_poll_time, (DateTime) - timestamp of the most recent poll.
  • num_messages_read, (UInt64) - number of messages read by the consumer.
  • last_commit_time, (DateTime) - timestamp of the most recent poll.
  • num_commits, (UInt64) - total number of commits for the consumer.
  • last_rebalance_time, (DateTime) - timestamp of the most recent Kafka rebalance
  • num_rebalance_revocations, (UInt64) - number of times the consumer was revoked its partitions
  • num_rebalance_assignments, (UInt64) - number of times the consumer was assigned to Kafka cluster
  • is_currently_used, (UInt8) - consumer is in use

Example:

SELECT *
FROM system.kafka_consumers
FORMAT Vertical

Row 1:
──────
database:                   test
table:                      kafka
consumer_id:                ClickHouse-instance-test-kafka-1caddc7f-f917-4bb1-ac55-e28bd103a4a0
assignments.topic:          ['system_kafka_cons']
assignments.partition_id:   [0]
assignments.current_offset: [18446744073709550615]
last_exception_time:        1970-01-01 00:00:00
last_exception:
last_poll_time:             2006-11-09 18:47:47
num_messages_read:          4
last_commit_time:           2006-11-10 04:39:40
num_commits:                1
last_rebalance_time:        1970-01-01 00:00:00
num_rebalance_revocations:  0
num_rebalance_assignments:  1
is_currently_used:          1