VPD issue affecting scalability of Application

Question

Hi all --
Our reporting application is using VPD to limit access to the data a user can see. Unfortunately, we are seeing scalability issues when using VPD, so we are wondering if any of you have any insight on what we're doing incorrectly. Here's the scenario:
Users may have access to multiple stores, so the VPD policy is returning a predicate that looks like this: branch_code in ('MNWIN','WIMAD'). Unfortunately with each predicate change we are getting a hard parse of the statement leading to degraded performance.
We have been playing with using sys_context to set the predicate and returning a predicate that looks like: branch_code in sys_context('BRANCH_CTX','BRANCH_CODE') but errors get returned from the policy predicate or the context doesn't get set correctly.
So a few questions:
1. Is this the appropriate forum in which to post this?
2. Is it possible to use sys_context in this way
3. What is the preferred method for using VPD in a nonunique environment (ie: users have access to multiple values)
Thanks!
Leigh Johnson
Fastenal Company

Answer 1

You are correct to use bind variables to expedite the SQL processing. From your code, it is failing because you need to double the single quotes:
RETURN 'branch_code in sys_context (''BRANCH_CTX'',''BRANCH_CODE'')';