JDBC Store Implementation

[maciejwalkowiak]

While DynamoDB and Redis are both natural candidates for storing idempotency keys and values due to their key-value nature and built-in TTL, for many applications that use only RDBMs it would be more convenient to not add new infrastructure just for idempotency purposes.

I am proposing to add a JDBC based implementation of the store. Either a generic one for all/most RDBMS, or one specific to Postgres.

[arun0009]

Interesting idea. It's definitely do-able but a few questions:

1. With a JDBC Store, the performance would be something to think about. Since we have to make that check while processing request we have to be quick enough while providing idempotency.
2. JDCB won't have a TTL feature, so think of some cron job event that runs and deletes idempotent rows once they expire. Can we use maybe Spring JDBC Template of JPA and try to implement it for Postgres/MySQL in one module? The way to delete the idempotent rows would possibly differ for Postgres & MySQL.