Why Does the Secondary Report LOST_EVENTS And What To Do
(Doc ID 1024297.1)
Last updated on JUNE 28, 2021
Applies to:MySQL Cluster - Version 4.1 and later
Geographic replication enables asynchronous replication across geographically separate clusters. This is often used for disaster recovery.
During MySQL Cluster geographical replication it might happen that the Secondary SQL Node is reporting the LOST_EVENTS incident. This happens whenever the SQL node looses connection to the cluster (either by a controlled or crashing restart) and is trying to make sure that the Secondary stops replicating. It does this to help protect against the secondary becoming out-of-sync.
As an example, suppose a MySQL server responsible for logging all updates executed in MySQL Cluster is restarted. Suppose further that there is a moment in which it will be unable to log any changes done in the cluster. This means that changes made using another SQL or API node will not be in the binary log and consequently not replicated. Therefore, a LOST_EVENTS incident is reported in the binary logs and handled as an error by the Secondary. Replication stops since data might be missing in the logs.
Below is an example of how the error is reported by the Secondary (edited for clarity):
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