10g: select ... from ... start with ... connect by ... breaks parallelism?

i have a strange effect, since we added a select ... from ... start with ... connect by ... SQL stmt.
Oracle doesn't tune anymore for parallel pipelined functions - which it did before.
I.e. i only get a single worker session for the parallel pipelined functions.
When i disable the SQL stmt, then everything works fine. Really strange is, that - when the SQL stmt is having this effect w/o being invoked.
I.e. when it's in the code, then it is currently "dead code" (unused), because it depends on set-up/configuration, which currently doesn't allow to actually use it.
So the first question is, why such select ... from ... start with ... connect by ... SQL stmt breaks parallelism. The second question how it does w/o being actually used?

• many thanks!

rgds,
Frank Received on Thu Feb 24 2011 - 01:14:05 CST