意外AWS RDS binlog删除后恢复Debezium MySQL连接器

Question

当Debezium在kafka连接中作为源运行时，如果在目标MySQL DB（Amazon RDS实例）上有一段时间没有更新，那么在一段时间后，我最终会出现以下错误。

[2018-04-25 21:30:14,526] INFO Step 0: Get all known binlogs from MySQL (io.debezium.connector.mysql.MySqlConnectorTask:310)
[2018-04-25 21:30:14,536] INFO Connector requires binlog file 'mysql-bin-changelog.002640', but MySQL only has mysql-bin-changelog.002663, mysql-bin-changelog.002664, mysql-bin-changelog.002665 (io.debezium.connector.mysql.MySqlConnectorTask:323)
[2018-04-25 21:30:14,536] INFO MySQL has the binlog file 'mysql-bin-changelog.002640' required by the connector (io.debezium.connector.mysql.MySqlConnectorTask:325)
[2018-04-25 21:30:14,536] INFO Stopping MySQL connector task (io.debezium.connector.mysql.MySqlConnectorTask:239)
[2018-04-25 21:30:14,536] INFO WorkerSourceTask{id=swiggy-connector-0} Committing offsets (org.apache.kafka.connect.runtime.WorkerSourceTask:328)
[2018-04-25 21:30:14,536] INFO WorkerSourceTask{id=swiggy-connector-0} flushing 0 outstanding messages for offset commit (org.apache.kafka.connect.runtime.WorkerSourceTask:345)
[2018-04-25 21:30:14,536] ERROR WorkerSourceTask{id=swiggy-connector-0} Task threw an uncaught and unrecoverable exception (org.apache.kafka.connect.runtime.WorkerTask:172)
org.apache.kafka.connect.errors.ConnectException: The connector is trying to read binlog starting at binlog file 'mysql-bin-changelog.002640', pos=470, skipping 4 events plus 0 rows, but this is no longer available on the server. Reconfigure the connector to use a snapshot when needed.
    at io.debezium.connector.mysql.MySqlConnectorTask.start(MySqlConnectorTask.java:117)
    at io.debezium.connector.common.BaseSourceTask.start(BaseSourceTask.java:45)
    at org.apache.kafka.connect.runtime.WorkerSourceTask.execute(WorkerSourceTask.java:164)
    at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:170)
    at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:214)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

当我去数据库检查MySQL中的binlog时

mysql> show binary logs;
+----------------------------+-----------+
| Log_name                   | File_size |
+----------------------------+-----------+
| mysql-bin-changelog.002664 |       479 |
| mysql-bin-changelog.002665 |       120 |
+----------------------------+-----------+


mysql> show binlog events;
+----------------------------+-----+-------------+------------+-------------+---------------------------------------------------------------------------------------------------------------------------------+
| Log_name                   | Pos | Event_type  | Server_id  | End_log_pos | Info                                                                                                                            |
+----------------------------+-----+-------------+------------+-------------+---------------------------------------------------------------------------------------------------------------------------------+
| mysql-bin-changelog.002664 |   4 | Format_desc | 1550192458 |         120 | Server ver: 5.6.39-log, Binlog ver: 4                                                                                           |
| mysql-bin-changelog.002664 | 120 | Query       | 1550192458 |         201 | BEGIN                                                                                                                           |
| mysql-bin-changelog.002664 | 201 | Query       | 1550192458 |         391 | use `mysql`; INSERT INTO mysql.rds_heartbeat2(id, value) values (1,1524671965007) ON DUPLICATE KEY UPDATE value = 1524671965007 |
| mysql-bin-changelog.002664 | 391 | Xid         | 1550192458 |         422 | COMMIT /* xid=308462 */                                                                                                         |
| mysql-bin-changelog.002664 | 422 | Rotate      | 1550192458 |         479 | mysql-bin-changelog.002665;pos=4                                                                                                |
+----------------------------+-----+-------------+------------+-------------+---------------------------------------------------------------------------------------------------------------------------------+

问题：

• 为什么Debezium是空闲的？为什么它在002640文件之后没有从MySQL中读取文件？
  这没有被任何服务使用。所以在Debezium可以读取之前不可能有太多的写入发生。
• 为什么Amazon MySQL RDS在没有任何活动发生时删除数据库日志文件？
  这是一个测试数据库，只有我在其中插入记录。所以这里没有发生外部应用程序活动。
• 有没有办法恢复Debezium连接器，并从MySQL当前可用的时间日志开始处理记录？（如果我不介意那些未读记录丢失）。
  我尝试重新启动工作，删除和添加连接器，但总是以相同的错误结束。
  唯一适用于恢复事件的解决方案
  • 删除Kafka Connect的离线主题。
  • 删除

Answer 1

请看心跳。间隔msconfig属性-这应该可以防止在高流量环境中，Debezium监视低流量表时出现这种情况。在这种情况下，可能会刷新binlog，但当前binlog坐标不会记录在偏移主题中。

关于简历——你可以通过修改主题从这种情况中恢复过来。在这里，您需要为服务器上可用的插件和binlog坐标插入偏移记录。Kafka·基普（Kafka KIP）是一个可以帮助解决这个问题的工具。现在您需要手动执行此操作。