Report performance - PL/SQL vs SQL type

Question

Hello,
Is it possible that report built as PL/SQL function returning SQL query is slower (much more) than common SQL report?
I’ve got a view, that I read data from. When I use SQL query report with variables in :PX_NAME format, it takes about 5 seconds to show the page. If I use PL/SQL report with variables in v('PX_NAME') format inside query string like:
'SELECT * FROM myview where myname like v(''P5_NAME'')';it takes about 3 minutes to get the same data.
Do you have any idea why?
Regards,
Przemek

Answer 1

It's hard to tell without knowing how many rows we are talking about, the CPU load, and so on, but in a heavily loaded system i can easily imagine that a query containing a call to V function might cause a not optimized access path, whereas the same query with a bind variable might work much better.
Said that, the rule of thumb is to use bind variables every time you can and avoid V as much as you can.
If you can do the same thing with :PX_NAME, use that, there is no justification for using V('PX_NAME').
Flavio
http://oraclequirks.blogspot.com