How the performance will increase with pipelined function.

Question

Respects all,
Can u please help to explain one example regarding which i have mentioned in the subject line.
Thanks

Answer 1

Hi,
pipelined functions don't "increase performance".
1) This is an entirely wrong way to think about Oracle features. There are no Oracle features that automatically "increase performance", like some sort of a "turbo" button (not even partitioning! not even indexes!). Most of the features can work both ways -- when used appropriately, they improve performance, when not, they can cripple it.
2) Pipelined functions are not about performance. They simply provide a way for you to SELECT from a PL/SQL function (which otherwise is impossible to do). Not only you can generate sets of values this way, but also you can join it with other tables/views, that can be very convenient. Pipelined functions can also be very convenient for generating formatted text reports they allow you to bypass limitations of long/lob data types). But none of this has to do with performance.
3) Pipelined functions are inevitably associated with row-by-row processing (because there is no way to pipe a set of rows at once). So when the choice is between returning a refcursor (from which you can do a bulk fetch), and using a pipelined function, from which you'll be returning rows one by one, and none of items listed in 2) applies, then chances are that pipelined function is going to be slower.
So whoever claimed that "pipelined functions increase performance", either he/she is incompetent, or you took his/her words out of the context or misintepreted them.
Best regards,
  Nikolay