AWS DMS 任务在 CDC 模式下运行一段时间后失败

Question

我在设置任务以初始迁移 + CDC 模式下将 RDS 数据库（PostgreSQL，引擎 10.15）中的数据迁移到 S3 存储桶时遇到问题。两个端点均已成功配置并测试。我已经创建了两次该任务，两次最多运行几个小时，第一次初始转储运行良好，并且也发生了一些增量转储，第二次仅初始转储完成并且没有增量转储在任务失败之前执行。

现在的错误消息是：

Last Error Task 'data-migration-bp-dev' was suspended after 9 successive recovery failures Stop Reason FATAL_ERROR Error Level FATAL_

但就在第一次失败之后：

Last Error An internal WAL conversational protocol error has occurred. Task error notification received from subtask 0, thread 0 reptask/replicationtask.c:2859 1020452 Error executing source loop; Stream component failed at subtask 0, component st_0_data-migration-rds-bp-dev; Stream component 'st_0_data-migration-rds-bp-dev' terminated reptask/replicationtask.c:2866 1020452 Stop Reason RECOVERABLE_ERROR Error Level RECOVERABLE

在 CloudWatch 日志中，我看到以下错误消息：

SOURCE_CAPTURE I: Streaming initiated successfully (postgres_pglogical.c:274)
SOURCE_CAPTURE I: #1 : Non-monotonic LSN sequence: Current LSN '00000000/00000000' < Previous LSN '000001E3/94016430'. Event is ignored. (postgres_endpoint_wal_engine.c:710)
SOURCE_CAPTURE I: Unable to resolve attributes for relation id '28804'. Aborting action. (postgres_pglogical.c:1643)
SOURCE_CAPTURE I: End of CDC / CAPTURE events for POSTGRES endpoint. (postgres_endpoint_capture.c:520)
SOURCE_CAPTURE I: CAPTURE ended with exceptions. (postgres_endpoint_capture.c:527)
SOURCE_CAPTURE E: Could not find relation id '28804' in hash. 1020483 (postgres_pglogical.c:1470)
SOURCE_CAPTURE E: Failed to parse relation from dml command 1020483 (postgres_pglogical.c:2515)
SOURCE_CAPTURE E: Failed to find relation id on target while processing message from source 1020452 (postgres_endpoint_wal_engine.c:805)
SOURCE_CAPTURE E: WAL stream loop ended abnormally. (STATUS_PROTOCOL_ERROR) 1020452 (postgres_endpoint_wal_engine.c:992)
SOURCE_CAPTURE E: WAL reader terminated with irrecoverable error. 1020452 (postgres_endpoint_capture.c:496)
TASK_MANAGER I: Task - data-migration-bp-dev is in ERROR state, updating starting status to AR_NOT_APPLICABLE (repository.c:5102)
SOURCE_CAPTURE E: Error executing source loop 1020452 (streamcomponent.c:1870)
TASK_MANAGER E: Stream component failed at subtask 0, component st_0_data-migration-rds-bp-dev 1020452 (subtask.c:1409)
SOURCE_CAPTURE E: Stream component 'st_0_data-migration-rds-bp-dev' terminated 1020452 (subtask.c:1578)
TASK_MANAGER E: Task error notification received from subtask 0, thread 0 1020452 (replicationtask.c:2859)
TASK_MANAGER E: Error executing source loop; Stream component failed at subtask 0, component st_0_data-migration-rds-bp-dev; Stream component 'st_0_data-migration-rds-bp-dev' terminated 1020452 (replicationtask.c:2866)
TASK_MANAGER E: Task 'data-migration-bp-dev' encountered a recoverable error, retry attempt # 0 (repository.c:5184)

在这一点上我应该提到，我们必须配置 pglogic 插件并重新启动数据库，但最终我们收到了一个错误，我们忽略了该错误，因为 DMS 任务是在该操作之后启动的。

ERROR: current database is not configured as pglogical node
HINT: create pglogical node first

我们失败的 DMS 任务问题是否与 pglogic 插件配置有关？如果是这样，我们如何配置它才能工作（我们的数据库引擎应该与它兼容，不是吗？）？如果没有，如何解决？

先感谢您！

Answer 1

如果将来有人遇到同样的错误，AWS 技术专家告诉我们如下：

pglogic插件存在一个（AWS 已知的）问题。该解决方案需要使用test_decoding插件来代替。

1. 通过在额外连接属性中指定pluginName=test_decoding，强制在DMS端点上使用test_decoding插件
2. 使用该端点创建新的DMS任务（使用旧任务可能会因任务与日志不同步而导致失败）

它确实解决了这个问题，但我们仍然不知道 DMS 文档中到处都强烈建议的插件的问题到底是什么（目前）。