Introduction

Follow the guide below for help upgrading your MySQL database engine while avoiding downtime to your Fivetran connector.

Environment

Connector: MySQL RDS

Resolution

1. Create a new read replica on the version you’re upgrading to
2. Create a new connector with this new read replica
3. Complete the historic sync
4. Begin incremental syncing
5. Turn off your existing connector
6. Upgrade the master

Context

Fivetran can connect to either your master or a read replica of your master MySQL database. When completing an upgrade of the database engine, AWS mandates that any read replicas are upgraded first .

Regardless of whether or not you’re currently using a read replica - and indeed, whether you plan to use the read replica in the future - you can use this process to ensure that there is no downtime in the data that you’re receiving as you can connect to a read replica temporarily or permanently to ensure that your data ingest is not affected by the database engine upgrade.

Considerations

The time between steps 4 and 5 should be as short as possible in order to avoid:

1. Running connectors in parallel and accruing MAR on duplicate rows of data
2. Pausing the new connector past the retention period of the binlogs; if this happened, a new historic sync would be required in order to maintain data integrity

There are considerations for upgrading your RDS instance that whilst not explicitly affecting Fivetran, should be factored into your upgrade path:

1. An upgrade to the master may change the parameter group assigned to the read replica; ensure that you check this setting after an upgrade to the master and revert it if required
2. There may be compatibility issues between versions that will need to be taken into account