The in-memory Flux database (HSQL) is restricted to one connection. If you use a real RDBMS such as Oracle, SQL, MySQL, Sybase, DB2, etc., then both flow charts will run simultaneously. Keep in mind that Flux will need a database connection for each concurrent flow.

The CONCURRENCY_LEVEL is the number of flow charts/threads that you would like to execute simultaneously. The MAX_CONNECTIONS value is the total number of connections that Flux can open to the database.

We recommend that MAX_CONNECTIONS=CONCURRENCY_LEVEL + 5. Flux will need some internal connections to the database to poll for available jobs to execute.