Query running for long post upgrade to Oracle 11g from 10g

Question

The below query is running for a very long time post upgrade of database from 10g to 11g.
SELECT default_supplier
  FROM (SELECT pv.vendor_name || '-'
               || pvsa.vendor_site_code default_supplier
          FROM mrp_item_sourcing_levels_v mislv,
               mfg_lookups ml1,
               mfg_lookups ml2,
               mfg_lookups ml3,
               mtl_system_items_b msib,
               po_vendors pv,
               po_vendor_sites_all pvsa
         WHERE msib.segment1 = :b1
           AND msib.organization_id = :b2
           AND mislv.inventory_item_id = msib.inventory_item_id
           AND mislv.organization_id = msib.organization_id
           AND ml1.lookup_type = 'MRP_SOURCING_RULE_TYPE'
           AND ml1.lookup_code = mislv.sourcing_rule_type
           AND ml2.lookup_type = 'MRP_ASSIGNMENT_TYPE'
           AND ml2.lookup_code = mislv.assignment_type
           AND pv.vendor_id = mislv.vendor_id
           AND pvsa.vendor_site_id = mislv.vendor_site_id
           AND pvsa.vendor_id = mislv.vendor_id
           AND ml3.lookup_type = 'MRP_SOURCE_TYPE'
           AND ml3.lookup_code = mislv.sourcing_level
           AND mislv.sourcing_level =
                  (SELECT MIN (sourcing_level)
                     FROM mrp_item_sourcing_levels_v
                    WHERE inventory_item_id = msib.inventory_item_id
                      AND organization_id = msib.organization_id)
        UNION
        SELECT ood.organization_code default_supplier
          FROM mrp_item_sourcing_levels_v mislv,
               mfg_lookups ml1,
               mfg_lookups ml2,
               mfg_lookups ml3,
               mtl_system_items_b msib,
               org_organization_definitions ood
         WHERE msib.segment1 = :b1
           AND msib.organization_id = :b2
           AND mislv.inventory_item_id = msib.inventory_item_id
           AND mislv.organization_id = msib.organization_id
           AND ml1.lookup_type = 'MRP_SOURCING_RULE_TYPE'
           AND ml1.lookup_code = mislv.sourcing_rule_type
           AND ml2.lookup_type = 'MRP_ASSIGNMENT_TYPE'
           AND ml2.lookup_code = mislv.assignment_type
           AND ml3.lookup_type = 'MRP_SOURCE_TYPE'
           AND ml3.lookup_code = mislv.sourcing_level
           AND ood.organization_id = mislv.source_organization_id
           AND mislv.sourcing_level =
                  (SELECT MIN (sourcing_level)
                     FROM mrp_item_sourcing_levels_v
                    WHERE inventory_item_id = msib.inventory_item_id
                      AND organization_id = msib.organization_id))
From the trace files, we see that the issue is with the seeded view, mrp_item_sourcing_levels_v.
Need pointers for fixing the performance.    

Answer 1

The ETRM says this about the view:
***** Warning: Oracle Internal Use Only *****
Oracle Corporation does not support access to Oracle
applications data using this object, except from standard Oracle Applications programs.
which is a powerful suggestion that you should not be addressing this view directly. Looking at the source code for the view, it has a bunch of UNIONs that may prevent view merging, and all the queries have loads of hints coded within them. So really, there is little you can do about this.
It looks pretty simple to re-write your query to avoid addressing this view, you are using it only to retrieve a couple of columns. If you look at the source code for the view you'll see that you can get them easily without going through the view.
John Watson
Oracle Certified Master DBA