How does Flink cache values that also do not exist in the database?

[Marco Villalobos-2]

How does Flink cache values that also do not exist in the database?

I would like to cache hits forever, but I would like to check items that do not exist in the database only every 15 minutes? Is there a way to set that up in the SQL / Table api?  Also, is there a way to set that up in Keyed State?

[Timo Walther]

Hi Marco,

when you say "database" are you refering to the JDBC connector or would
you like to perform a JDBC query within some UDF? In the latter case, I
would recommend to use Flink's ProcessFunction because you can store the
cache hits in state (and thus keep them forever). SQL/Table API does not
expose state functionality. Aggregate functions are the only type of
functions that are stateful but not useful in this case I guess.

Regards,
Timo

On 07.12.20 17:14, Marco Villalobos wrote:
> How does Flink cache values that also do not exist in the database?
>
> I would like to cache hits forever, but I would like to check items that do not exist in the database only every 15 minutes? Is there a way to set that up in the SQL / Table api?  Also, is there a way to set that up in Keyed State?
>