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> 包含通过流式引擎接收且解析出错的消息信息的系统表。

# system.dead_letter_queue

<div id="description">
  ## 描述
</div>

包含通过流式引擎接收且解析出错的消息信息。目前已针对 Kafka 和 RabbitMQ 实现。

可通过将引擎特定的 `handle_error_mode` 设置指定为 `dead_letter_queue` 来启用日志记录。

数据的刷新周期在服务器设置部分 [dead\_letter\_queue](/zh/reference/settings/server-settings/settings#dead_letter_queue) 的 `flush_interval_milliseconds` 参数中设置。要强制刷新，请使用 [SYSTEM FLUSH LOGS](/zh/reference/statements/system#flush-logs) 查询。

ClickHouse 不会自动从该表中删除数据。更多详情，请参阅 [简介](/zh/reference/system-tables/overview#system-tables-introduction)。

<div id="columns">
  ## 列
</div>

* `table_engine` ([Enum8('Kafka' = 1, 'RabbitMQ' = 2)](/zh/reference/data-types/enum)) — 流类型。可能的值：'Kafka'、'RabbitMQ'。
* `event_date` ([Date](/zh/reference/data-types/date)) — 消费消息的日期。
* `event_time` ([DateTime](/zh/reference/data-types/datetime)) — 消费消息的日期和时间。
* `event_time_microseconds` ([DateTime64(6)](/zh/reference/data-types/datetime64)) — 查询开始时间，精度为微秒。
* `database` ([LowCardinality(String)](/zh/reference/data-types/lowcardinality)) — Kafka 表所属的 ClickHouse 数据库。
* `table` ([LowCardinality(String)](/zh/reference/data-types/lowcardinality)) — ClickHouse 表名。
* `error` ([String](/zh/reference/data-types/string)) — 错误信息。
* `raw_message` ([String](/zh/reference/data-types/string)) — 消息体。
* `kafka_topic_name` ([String](/zh/reference/data-types/string)) — Kafka topic 名称。
* `kafka_partition` ([UInt64](/zh/reference/data-types/int-uint)) — topic 的 Kafka 分区。
* `kafka_offset` ([UInt64](/zh/reference/data-types/int-uint)) — 消息的 Kafka 偏移量。
* `kafka_key` ([String](/zh/reference/data-types/string)) — 消息的 Kafka 键。
* `rabbitmq_exchange_name` ([String](/zh/reference/data-types/string)) — RabbitMQ exchange 名称。
* `rabbitmq_message_id` ([String](/zh/reference/data-types/string)) — RabbitMQ 消息 ID。
* `rabbitmq_message_timestamp` ([DateTime](/zh/reference/data-types/datetime)) — RabbitMQ 消息时间戳。
* `rabbitmq_message_redelivered` ([UInt8](/zh/reference/data-types/int-uint)) — RabbitMQ 重新投递标志。
* `rabbitmq_message_delivery_tag` ([UInt64](/zh/reference/data-types/int-uint)) — RabbitMQ 投递标签。
* `rabbitmq_channel_id` ([String](/zh/reference/data-types/string)) — RabbitMQ 通道 ID。

<div id="example">
  ## 示例
</div>

```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)

```

<div id="see-also">
  ## 另请参阅
</div>

* [Kafka](/zh/reference/engines/table-engines/integrations/kafka) - Kafka 引擎
* [system.kafka\_consumers](/zh/reference/system-tables/kafka_consumers) — `kafka_consumers` 系统表的说明，包含 Kafka 消费者的统计信息、错误等内容。