Help needed in query tuning

Question

Hi All,
I am using the following queries in formula columns of a 6i report. The query count for these queries as seen from the trc file is very high, which is causing performance issues in the report.
Can anyone please help me to tune these queries.
SELECT ROUND (SUM (pld.denom_burdened_cost))
FROM pa_project_asset_lines_v pl,
gl_code_combinations glcc,
pa_asset_line_details_v pld
WHERE pl.project_asset_line_detail_id = pld.project_asset_line_detail_id
AND glcc.code_combination_id = pl.cip_ccid
AND transfer_status_code = 'T'
AND pld.project_id = :b1
AND glcc.segment2 = '131340'
Query Count - 1579401
SELECT SUM (DECODE (ei.system_linkage_function,
'ST', DECODE (pa_security.view_labor_costs (:b1),
'Y', ei.project_burdened_cost,
NULL
'OT', DECODE (pa_security.view_labor_costs (:b1),
'Y', ei.project_burdened_cost,
NULL
ei.project_burdened_cost
) aa
FROM pa_expenditure_items_all ei, pa_tasks t
WHERE ei.project_id = :b1
AND pa_expenditures_utils.get_latest_gl_date (ei.expenditure_item_id)
BETWEEN :b4
AND :b5
AND ei.org_id = fnd_profile.VALUE ('ORG_ID')
AND ei.project_id = t.project_id
AND NVL (t.billable_flag, 'N') = 'N'
Query Count - 1969414
SELECT SUM (DECODE (ei.system_linkage_function,
'ST', DECODE (pa_security.view_labor_costs (:b1),
'Y', ei.project_burdened_cost,
NULL
'OT', DECODE (pa_security.view_labor_costs (:b1),
'Y', ei.project_burdened_cost,
NULL
ei.project_burdened_cost
) aa
FROM pa_cost_distribution_lines_all pcd,
gl_code_combinations glcc,
pa_expenditure_items_all ei,
pa_tasks t
WHERE ei.project_id = :b1
AND pa_expenditures_utils.get_latest_gl_date (ei.expenditure_item_id)
BETWEEN :b4
AND :b5
AND ei.org_id = fnd_profile.VALUE ('ORG_ID')
AND pcd.dr_code_combination_id = glcc.code_combination_id
AND glcc.segment2 != '131340'
AND ei.project_id = pcd.project_id
AND ei.expenditure_item_id = pcd.expenditure_item_id
AND t.project_id = ei.project_id
AND t.billable_flag = 'Y'
Query Count - 1973901
Regards,
Shruti

Answer 1

This statement
SELECT SUM (DECODE (ei.system_linkage_function,
'ST', DECODE (pa_security.view_labor_costs (:b1),
'Y', ei.project_burdened_cost,
NULL
'OT', DECODE (pa_security.view_labor_costs (:b1),
'Y', ei.project_burdened_cost,
NULL
ei.project_burdened_cost
) aa
FROM pa_expenditure_items_all ei, pa_tasks t
WHERE ei.project_id = :b1
AND pa_expenditures_utils.get_latest_gl_date (ei.expenditure_item_id)
BETWEEN :b4
AND :b5
AND ei.org_id = fnd_profile.VALUE ('ORG_ID')
AND ei.project_id = t.project_id
AND NVL (t.billable_flag, 'N') = 'N'uses at least 3 different functions inside the SQL.
<ul><li>pa_security.view_labor_costs (:b1)</li>
<li>fnd_profile.VALUE ('ORG_ID')</li>
<li>pa_expenditures_utils.get_latest_gl_date (ei.expenditure_item_id)</li>
</ul>
Each function call might result in a context switch from SQL to pl/SQL and back. This is expensive and slow. For each line 4 functions are called. Which means 8 context switches per base line. In your case aproximately 16 million switches.
You can try to avoid this context switch.
The first and second function an be encapsulated in a with query wich should result in a single call. The logic in the second function should be rewritten iinto pure SQL.
This can make a huge difference.
example untested
with singlerowdata as (select pa_security.view_labor_costs (:b1) v_labor_costs, fnd_profile.VALUE ('ORG_ID') profile_org_id from dual)
SELECT SUM (DECODE (ei.system_linkage_function,
  'ST', DECODE (s.v_labor_costs,
    'Y', ei.project_burdened_cost,
    NULL
  'OT', DECODE (s.v_labor_costs,
  'Y', ei.project_burdened_cost,
  NULL
ei.project_burdened_cost
) aa
FROM pa_expenditure_items_all ei, pa_tasks t, singlerowdata s
WHERE ei.project_id = :b1
/* "the latest date can also be found with an analytic function, but there is not enough information to show how to do it here"
This would potentially improve the performance even more. */
AND (select max(datecolumn) from pa_expenditure_items x where x.id = ei.expenditure_item_id) BETWEEN :b4 AND :b5
AND ei.org_id = s.profile_org_id
AND ei.project_id = t.project_id
AND NVL (t.billable_flag, 'N') = 'N'