I’m no DBA, but this suggests that the Database side decides it doesn’t want to play anymore and close the connection their side.

If I see this I’d call the DBA to see if there’s anything they can do to help. Maybe there’s some timeout setup on the db side that they could adjust? Otherwise can that SQL be tuned to run faster…?

If a problem occurs at the very beginning of the step execution, it is likely due to a stale connection. The Runtime Server, by default, keeps a pool of up to 10 open database connections. Some database engines do not like this behavior and close connections after a period of inactivity. To address this, you can either:

• Set maxIdleSize to 0, so connections are not reused.
• Set maxAge to close connections after a period of time.
• Include validationQuery, so each connection is checked before use.

More details could be found in Runtime Configuration :: Ataccama ONE

In addition you can also try to run the SQL via a query tool and see how that goes. If you then also encounter the problem you better contact a DBA, otherwise the suggestion by Kislyakov seems most appropriate.

Thank you for all the great ideas & solutions provided ​@may_kwok, ​@AKislyakov, and ​@Albert de Ruiter  ​@Ajeesh_G does this help? if yes, please mark a best answer ‍♀️