Shared DB connection is a connection which is exactly the same if you get it with the same name. Getting locks this way is pretty easy and you can be happy only to have locks and no other problems.
I strongly suggest to think about if it is a good idea to use exactly the same connection for multiple jobs. I think the transaction management will be a nightmare!
If you want to spare connection or reuse them use connections with the Datasource Alias. In normal Talend jobs outside a Talend Runtime you cannot setup a database connection pool but here you can use here custom components:
https://github.com/jlolling/talendcomp_tDatabaseConnectionPool
You can download the components from the Release section on the right side there.
