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59 lines
2.5 KiB
Markdown
59 lines
2.5 KiB
Markdown
---
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slug: /en/operations/system-tables/kafka_consumers
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---
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# kafka_consumers
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Contains information about Kafka consumers.
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Applicable for [Kafka table engine](../../engines/table-engines/integrations/kafka) (native ClickHouse integration)
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Columns:
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- `database` (String) - database of the table with Kafka Engine.
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- `table` (String) - name of the table with Kafka Engine.
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- `consumer_id` (String) - Kafka consumer identifier. Note, that a table can have many consumers. Specified by `kafka_num_consumers` parameter.
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- `assignments.topic` (Array(String)) - Kafka topic.
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- `assignments.partition_id` (Array(Int32)) - Kafka partition id. Note, that only one consumer can be assigned to a partition.
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- `assignments.current_offset` (Array(Int64)) - current offset.
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- `exceptions.time`, (Array(DateTime)) - timestamp when the 10 most recent exceptions were generated.
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- `exceptions.text`, (Array(String)) - text of 10 most recent exceptions.
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- `last_poll_time`, (DateTime) - timestamp of the most recent poll.
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- `num_messages_read`, (UInt64) - number of messages read by the consumer.
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- `last_commit_time`, (DateTime) - timestamp of the most recent poll.
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- `num_commits`, (UInt64) - total number of commits for the consumer.
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- `last_rebalance_time`, (DateTime) - timestamp of the most recent Kafka rebalance
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- `num_rebalance_revocations`, (UInt64) - number of times the consumer was revoked its partitions
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- `num_rebalance_assignments`, (UInt64) - number of times the consumer was assigned to Kafka cluster
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- `is_currently_used`, (UInt8) - consumer is in use
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- `rdkafka_stat` (String) - library internal statistic. See https://github.com/ClickHouse/librdkafka/blob/master/STATISTICS.md . Set `statistics_interval_ms` to 0 disable, default is 3000 (once in three seconds).
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Example:
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``` sql
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SELECT *
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FROM system.kafka_consumers
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FORMAT Vertical
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```
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``` text
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Row 1:
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──────
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database: test
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table: kafka
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consumer_id: ClickHouse-instance-test-kafka-1caddc7f-f917-4bb1-ac55-e28bd103a4a0
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assignments.topic: ['system_kafka_cons']
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assignments.partition_id: [0]
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assignments.current_offset: [18446744073709550615]
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exceptions.time: []
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exceptions.text: []
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last_poll_time: 2006-11-09 18:47:47
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num_messages_read: 4
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last_commit_time: 2006-11-10 04:39:40
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num_commits: 1
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last_rebalance_time: 1970-01-01 00:00:00
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num_rebalance_revocations: 0
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num_rebalance_assignments: 1
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is_currently_used: 1
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rdkafka_stat: {...}
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```
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