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> System table containing information about messages received via a streaming engine and parsed with errors.

# system.dead_letter_queue

<h2 id="description">
  Description
</h2>

Contains information about messages received via a streaming engine and parsed with errors. Currently implemented for Kafka and RabbitMQ.

Logging is enabled by specifying `dead_letter_queue` for the engine specific `handle_error_mode` setting.

The flushing period of data is set in `flush_interval_milliseconds` parameter of the [dead\_letter\_queue](/reference/settings/server-settings/settings#dead_letter_queue) server settings section. To force flushing, use the [SYSTEM FLUSH LOGS](/reference/statements/system#flush-logs) query.

ClickHouse does not delete data from the table automatically. See [Introduction](/reference/system-tables/overview#system-tables-introduction) for more details.

<h2 id="columns">
  Columns
</h2>

* `table_engine` ([Enum8('Kafka' = 1, 'RabbitMQ' = 2)](/reference/data-types/enum)) — Stream type. Possible values: 'Kafka', 'RabbitMQ'.
* `event_date` ([Date](/reference/data-types/date)) — Message consuming date.
* `event_time` ([DateTime](/reference/data-types/datetime)) — Message consuming date and time.
* `event_time_microseconds` ([DateTime64(6)](/reference/data-types/datetime64)) — Query starting time with microseconds precision.
* `database` ([LowCardinality(String)](/reference/data-types/lowcardinality)) — ClickHouse database Kafka table belongs to.
* `table` ([LowCardinality(String)](/reference/data-types/lowcardinality)) — ClickHouse table name.
* `error` ([String](/reference/data-types/string)) — Error text.
* `raw_message` ([String](/reference/data-types/string)) — Message body.
* `kafka_topic_name` ([String](/reference/data-types/string)) — Kafka topic name.
* `kafka_partition` ([UInt64](/reference/data-types/int-uint)) — Kafka partition of the topic.
* `kafka_offset` ([UInt64](/reference/data-types/int-uint)) — Kafka offset of the message.
* `kafka_key` ([String](/reference/data-types/string)) — Kafka key of the message.
* `rabbitmq_exchange_name` ([String](/reference/data-types/string)) — RabbitMQ exchange name.
* `rabbitmq_message_id` ([String](/reference/data-types/string)) — RabbitMQ message id.
* `rabbitmq_message_timestamp` ([DateTime](/reference/data-types/datetime)) — RabbitMQ message timestamp.
* `rabbitmq_message_redelivered` ([UInt8](/reference/data-types/int-uint)) — RabbitMQ redelivered flag.
* `rabbitmq_message_delivery_tag` ([UInt64](/reference/data-types/int-uint)) — RabbitMQ delivery tag.
* `rabbitmq_channel_id` ([String](/reference/data-types/string)) — RabbitMQ channel id.

<h2 id="example">
  Example
</h2>

```sql title="Query" theme={null}
SELECT * FROM system.dead_letter_queue LIMIT 1 \G;
```

```text title="Response" theme={null}
Row 1:
──────
table_engine:                  Kafka
event_date:                    2025-05-01
event_time:                    2025-05-01 10:34:53
event_time_microseconds:       2025-05-01 10:34:53.910773
database:                      default
table:                         kafka
error:                         Cannot parse input: expected '\t' before: 'qwertyuiop': (at row 1)
:
Row 1:
Column 0,   name: key,   type: UInt64, ERROR: text "qwertyuiop" is not like UInt64
raw_message:                   qwertyuiop
kafka_topic_name:              TSV_dead_letter_queue_err_1746095689
kafka_partition:               0
kafka_offset:                  0
kafka_key:
rabbitmq_exchange_name:
rabbitmq_message_id:
rabbitmq_message_timestamp:    1970-01-01 00:00:00
rabbitmq_message_redelivered:  0
rabbitmq_message_delivery_tag: 0
rabbitmq_channel_id:

Row 2:
──────
table_engine:                  Kafka
event_date:                    2025-05-01
event_time:                    2025-05-01 10:34:53
event_time_microseconds:       2025-05-01 10:34:53.910944
database:                      default
table:                         kafka
error:                         Cannot parse input: expected '\t' before: 'asdfghjkl': (at row 1)
:
Row 1:
Column 0,   name: key,   type: UInt64, ERROR: text "asdfghjkl" is not like UInt64
raw_message:                   asdfghjkl
kafka_topic_name:              TSV_dead_letter_queue_err_1746095689
kafka_partition:               0
kafka_offset:                  0
kafka_key:
rabbitmq_exchange_name:
rabbitmq_message_id:
rabbitmq_message_timestamp:    1970-01-01 00:00:00
rabbitmq_message_redelivered:  0
rabbitmq_message_delivery_tag: 0
rabbitmq_channel_id:

Row 3:
──────
table_engine:                  Kafka
event_date:                    2025-05-01
event_time:                    2025-05-01 10:34:53
event_time_microseconds:       2025-05-01 10:34:53.911092
database:                      default
table:                         kafka
error:                         Cannot parse input: expected '\t' before: 'zxcvbnm': (at row 1)
:
Row 1:
Column 0,   name: key,   type: UInt64, ERROR: text "zxcvbnm" is not like UInt64
raw_message:                   zxcvbnm
kafka_topic_name:              TSV_dead_letter_queue_err_1746095689
kafka_partition:               0
kafka_offset:                  0
kafka_key:
rabbitmq_exchange_name:
rabbitmq_message_id:
rabbitmq_message_timestamp:    1970-01-01 00:00:00
rabbitmq_message_redelivered:  0
rabbitmq_message_delivery_tag: 0
rabbitmq_channel_id:
 (test.py:78, dead_letter_queue_test)

```

<h2 id="see-also">
  See also
</h2>

* [Kafka](/reference/engines/table-engines/integrations/kafka) - Kafka Engine
* [system.kafka\_consumers](/reference/system-tables/kafka_consumers) — Description of the `kafka_consumers` system table which contains information like statistics and errors about Kafka consumers.