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Querying in ClickHouse Cloud

The data in this system table is held locally on each node in ClickHouse Cloud. Obtaining a complete view of all data, therefore, requires the `clusterAllReplicas` function. See [here](/docs/operations/system-tables/overview#system-tables-in-clickhouse-cloud) for further details.

Contains information about Kafka consumers.
Applicable for [Kafka table engine](/docs/engines/table-engines/integrations/kafka) (native ClickHouse integration)

Columns:

- `database` ([String](/docs/sql-reference/data-types)) — Database of the table with Kafka Engine.
- `table` ([String](/docs/sql-reference/data-types)) — Name of the table with Kafka Engine.
- `consumer_id` ([String](/docs/sql-reference/data-types)) — Kafka consumer identifier. Note, that a table can have many consumers. Specified by `kafka_num_consumers` parameter.
- `assignments.topic` ([Array(String)](/docs/sql-reference/data-types)) — Kafka topic.
- `assignments.partition_id` ([Array(Int32)](/docs/sql-reference/data-types)) — Kafka partition id. Note, that only one consumer can be assigned to a partition.
- `assignments.current_offset` ([Array(Int64)](/docs/sql-reference/data-types)) — Current offset.
- `assignments.intent_size` ([Array(Nullable(Int64))](/docs/sql-reference/data-types)) — The number of pushed, but not yet committed messages in new StorageKafka.
- `exceptions.time` ([Array(DateTime)](/docs/sql-reference/data-types)) — Timestamp when the 10 most recent exceptions were generated.
- `exceptions.text` ([Array(String)](/docs/sql-reference/data-types)) — Text of 10 most recent exceptions.
- `last_poll_time` ([DateTime](/docs/sql-reference/data-types)) — Timestamp of the most recent poll.
- `num_messages_read` ([UInt64](/docs/sql-reference/data-types)) — Number of messages read by the consumer.
- `last_commit_time` ([DateTime](/docs/sql-reference/data-types)) — Timestamp of the most recent poll.
- `num_commits` ([UInt64](/docs/sql-reference/data-types)) — Total number of commits for the consumer.
- `last_rebalance_time` ([DateTime](/docs/sql-reference/data-types)) — Timestamp of the most recent Kafka rebalance.
- `num_rebalance_revocations` ([UInt64](/docs/sql-reference/data-types)) — Number of times the consumer was revoked its partitions.
- `num_rebalance_assignments` ([UInt64](/docs/sql-reference/data-types)) — Number of times the consumer was assigned to Kafka cluster.
- `is_currently_used` ([UInt8](/docs/sql-reference/data-types)) — The flag which shows whether the consumer is in use.
- `last_used` ([DateTime64(6)](/docs/sql-reference/data-types)) — The last time this consumer was in use.
- `rdkafka_stat` ([String](/docs/sql-reference/data-types)) — Library internal statistic. Set statistics\_interval\_ms to 0 disable, default is 3000 (once in three seconds).
- `dependencies` ([Array(Array(String))](/docs/sql-reference/data-types)) — Transitive database dependencies.
- `missing_dependencies` ([Array(Array(String))](/docs/sql-reference/data-types)) — Missing transitive database dependencies.

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]
exceptions.time:               []
exceptions.text:               []
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
rdkafka_stat:                  {...}
dependencies:                  [['test.mv2','test.target2'],['test.mv1','test.target1']]
missing_dependencies:          []
```

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