Dynamic query with HibernateCritera API & Oracle - performance

Question

I have to use Hibernate and retrieve data from Oracle but the problem is, that the number of parameters passed to the query is not always the same.

For the sake of simpl

Answer 1

I've worked with IN(...) queries that had up to a 1000 of ids in that list; I can guarantee you that it does not take several seconds to parse / prepare / cache a statement.

Hibernate does indeed auto-expand the parameter list you specify using the actual number of elements in the list you pass, so if you really wanted to keep it "fixed" at a certain level all you need to do is to append enough -1s to the end. However, this is most certainly not the problem especially since we're talking about speeding up the first query run - no statements have been prepared / cached yet anyway.

Did you look at the execution plans for your queries? Both via explain plan and autotrace enabled? Do they differ when you have 30 elements and 120 elements in your list? Does your actual query really look like "select ... from table where id in (...)" you've posted or is it more complex? I'm willing to bet that somewhere between 30 and 120 elements Oracle decides (perhaps mistakenly) that it'll be faster not to use an index, which is why you're seeing the time increase.