Why is RDS for MySQL setting replica_exec_mode to IDEMPOTENT by default?

Question

The default parameter group for MySQL8.0 sets `replica_exec_mode` to `IDEMPOTENT`. I couldn't find any documentation why RDS decided to do it.
The default is `STRICT`.  IDEMPOTENT would skip errors and might cause data inconsistency, why does RDS set it so?
I get it, I can change it, but I am wondering what's RDS' rationale to set it as default.

Answer

Hi rahul342,

Thanks for your question.

I do see the default being set as "IDEMPOTENT" by the RDS MySQL instances but the default value as per the official MySQL docs, the STRICT mode is the default value.

https://dev.mysql.com/doc/refman/8.0/en/replication-options-replica.html

I have reached out to my internal team on this and they have agreed to change the default value in the future releases for RDS MySQL.

But till then, you can change the value manually if required.

Why is RDS for MySQL setting replica_exec_mode to IDEMPOTENT by default?

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