Help me to reduce buffer gets of following query

Question

Buffer gets with this query is 460K.
We want to reduce it drastically.
SELECT temp21.resource_code
,temp21.employee_type employee_type
     ,temp21.resource_name resource_name
     ,temp21.manager_id
     ,temp21.manager_name
     ,temp21.period_start
     ,temp21.period_finish
     ,temp21.avail_hours
     ,temp21.act_hours
     ,temp21.timesheet_status timesheet_status
     ,temp21.email,temp21.ouc
     ,temp21.work_country
     ,f.level1_unit_id level1_id
     ,f.level2_unit_id level2_id
     ,f.level3_unit_id level3_id
     ,f.level4_unit_id level4_id
     ,f.level5_unit_id level5_id
     ,f.level6_unit_id level6_id
     ,f.level7_unit_id level7_id
     ,f.level8_unit_id level8_id
     ,f.level9_unit_id level9_id
     ,f.level10_unit_id level10_id
     ,f.level1_name
     ,f.level2_name
     ,f.level3_name
     ,f.level4_name
     ,f.level5_name
     ,f.level6_name
     ,f.level7_name
     ,f.level8_name
     ,f.level9_name
     ,f.level10_name
FROM (SELECT avail.res_id
     ,avail.resource_code
          ,avail.employee_type
                    ,avail.person_type
                    ,avail.resource_name
                    ,avail.manager_id
                    ,avail.manager_name
                    ,avail.period_start
                    ,avail.period_finish
                    ,avail.avail_hours
                    ,NVL(act.act_hours,0) act_hours
                    ,act.timesheet_status
                    ,avail.prid
                    ,avail.email
                    ,avail.ouc
                    ,avail.work_country
FROM (SELECT /*+ALL_ROWS*/r.id res_id
     ,lk.name employee_type
          ,r.unique_name resource_code
                                        ,r.person_type
                                        ,r.first_name||' '||r.last_name resource_name
                                        ,r.manager_id manager_id
                                        ,r1.first_name||' '||r1.last_name manager_name
                                        ,TRUNC(tp.prstart) period_start
                                        ,TRUNC(tp.prfinish - 1) period_finish
                                        ,NVL(o.gs_hrs_avail_week,0) avail_hours
                                        ,r.email
                                        ,o.ouc
                                        ,o.work_country
                                        ,tp.prid
               FROM niku.ODF_CA_RESOURCE o
               ,niku.SRM_RESOURCES r
                    ,niku.SRM_RESOURCES r1
                    ,niku.PRTIMEPERIOD tp
                    ,niku.CMN_SEC_USER_GROUPS usr_grp
                    ,niku.CMN_SEC_GROUPS grp
                    ,(SELECT
                         NLS.NAME
                         ,LKP.ID
                         FROM CMN_CAPTIONS_NLS NLS,CMN_LOOKUPS LKP
                         WHERE NLS.PK_ID=LKP.ID
                         AND LKP.LOOKUP_TYPE='SRM_RESOURCE_TYPE'
                         AND NLS.TABLE_NAME='CMN_LOOKUPS'
                         AND NLS.LANGUAGE_CODE='en') lk
WHERE r.id=o.id
AND r1.user_id(+)=r.manager_id
AND r.user_id=usr_grp.user_id
AND usr_grp.GROUP_ID=grp.id
     AND r.person_type=lk.id
AND r.is_active = 1
AND r1.is_active = 1
AND grp.GROUP_CODE='gs_tb'
AND tp.prisopen = 1
) avail
               ,(SELECT r.id
               ,tp.prid
                                        ,SUM(NVL(practsum,0)/3600) act_hours
                                        ,ts.prstatus timesheet_status
FROM niku.SRM_RESOURCES r
               ,niku.PRTIMESHEET ts
SELECT /*+ALL_ROWS*/ MAX(prid) prid
                         ,prtimeperiodid
                         ,prresourceid
FROM niku.prtimesheet
                         GROUP BY prtimeperiodid,prresourceid
) ts_new
                    ,niku.PRTIMEENTRY te
                    ,niku.PRTIMEPERIOD tp
                    ,niku.CMN_SEC_USER_GROUPS usr_grp
                    ,niku.CMN_SEC_GROUPS grp
WHERE ts.prid=ts_new.prid
AND ts.prtimeperiodid=ts_new.prtimeperiodid
AND ts.prresourceid=ts_new.prresourceid
AND r.id=ts.PRRESOURCEID
AND ts.PRID=te.PRTIMESHEETID
AND ts.PRTIMEPERIODID=tp.prid
AND usr_grp.USER_ID=r.USER_ID
AND grp.id=usr_grp.group_id
AND r.is_active=1
AND tp.PRISOPEN=1
AND ts.prstatus not in(0,2,5)
AND grp.group_code='gs_tb'
AND TRUNC(tp.PRSTART) >= TRUNC(TO_DATE('7/24/2006','MM/DD/YYYY HH:MI:SS AM'))
AND TRUNC(tp.PRFINISH-1) <= TRUNC(TO_DATE('9/25/2006','MM/DD/YYYY HH:MI:SS AM'))
          GROUP BY r.ID
               ,tp.PRID
                         ,ts.prstatus) act
WHERE act.id(+) = avail.res_id
AND act.prid(+) = avail.prid
AND (avail.avail_hours - NVL(act.act_hours,0) > 0))temp21
     ,prj_obs_associations o1
     ,nbi_dim_obs f
     WHERE 1=1
AND temp21.prid in (SELECT prid
FROM PRTIMEPERIOD
WHERE TRUNC(PRSTART) >= TRUNC(TO_DATE('7/24/2006','MM/DD/YYYY HH:MI:SS AM'))
AND TRUNC(PRFINISH-1) <= TRUNC(TO_DATE('9/25/2006','MM/DD/YYYY HH:MI:SS AM'))
AND
temp21.res_id = o1.record_id
AND o1.unit_id = f.obs_unit_id
AND o1.table_name = 'SRM_RESOURCES'
AND f.obs_type_id = 5000009
AND f.level5_unit_id = 5013334
                                   ORDER BY temp21.manager_name
                                   ,temp21.manager_id
                                   ,temp21.resource_name
                                   ,temp21.resource_code
                                   ,temp21.period_start
                                   ,temp21.period_finish
                                   ,temp21.timesheet_status

Answer 1

...Also
AND TRUNC(tp.PRSTART) >= TRUNC(TO_DATE('7/24/2006','MM/DD/YYYY HH:MI:SS AM'))
AND TRUNC(tp.PRFINISH-1) <= TRUNC(TO_DATE('9/25/2006','MM/DD/YYYY HH:MI:SS AM'))Although this won't fail, you have specified the time portion of the date without supplying data to be converted....which you don't need as it will automatically be set to midnight if you don't specify it.
In addition, you are applying the TRUNC function to the column you are comparing which will prevent any indexes from being used. You should perform the arithmetic on the litterals, not the columns, and set up the range correctly:
AND tp.PRSTART >= TO_DATE('7/24/2006','MM/DD/YYYY)
AND tp.PRFINISH < TO_DATE('9/25/2006','MM/DD/YYYY) + 2This should yeild the same result and will allow any indexes to be used.
Without a formatted execution plan and more info from you, this is just a wild guess as to what part of the problem might be.
HTH
David
After a further look, the cartesian product appears to be in the bold section:
SELECT
     temp21.resource_code
     ,temp21.employee_type employee_type
     ,temp21.resource_name resource_name
     ,temp21.manager_id
     ,temp21.manager_name
     ,temp21.period_start
     ,temp21.period_finish
     ,temp21.avail_hours
     ,temp21.act_hours
     ,temp21.timesheet_status timesheet_status
     ,temp21.email,temp21.ouc
     ,temp21.work_country
     ,f.level1_unit_id level1_id
     ,f.level2_unit_id level2_id
     ,f.level3_unit_id level3_id
     ,f.level4_unit_id level4_id
     ,f.level5_unit_id level5_id
     ,f.level6_unit_id level6_id
     ,f.level7_unit_id level7_id
     ,f.level8_unit_id level8_id
     ,f.level9_unit_id level9_id
     ,f.level10_unit_id level10_id
     ,f.level1_name
     ,f.level2_name
     ,f.level3_name
     ,f.level4_name
     ,f.level5_name
     ,f.level6_name
     ,f.level7_name
     ,f.level8_name
     ,f.level9_name
     ,f.level10_name
FROM (     SELECT
               avail.res_id
               ,avail.resource_code
               ,avail.employee_type
               ,avail.person_type
               ,avail.resource_name
               ,avail.manager_id
               ,avail.manager_name
               ,avail.period_start
               ,avail.period_finish
               ,avail.avail_hours
               ,NVL(act.act_hours,0) act_hours
               ,act.timesheet_status
               ,avail.prid
               ,avail.email
               ,avail.ouc
               ,avail.work_country
          FROM (     SELECT /*+ALL_ROWS*/
                         r.id res_id
                         ,lk.name employee_type
                         ,r.unique_name resource_code
                         ,r.person_type
                         ,r.first_name||' '||r.last_name resource_name
                         ,r.manager_id manager_id
                         ,r1.first_name||' '||r1.last_name manager_name
                         ,TRUNC(tp.prstart) period_start
                         ,TRUNC(tp.prfinish - 1) period_finish
                         ,NVL(o.gs_hrs_avail_week,0) avail_hours
                         ,r.email
                         ,o.ouc
                         ,o.work_country
                         ,tp.prid
                    FROM
                         niku.ODF_CA_RESOURCE o
                         ,niku.SRM_RESOURCES r
                         ,niku.SRM_RESOURCES r1
                         ,niku.PRTIMEPERIOD tp
                         ,niku.CMN_SEC_USER_GROUPS usr_grp
                         ,niku.CMN_SEC_GROUPS grp
                         ,(     SELECT
                                   NLS.NAME
                                   ,LKP.ID
                              FROM
                                   CMN_CAPTIONS_NLS NLS,
                                   CMN_LOOKUPS LKP
                              WHERE
                                   NLS.PK_ID=LKP.ID
                              AND LKP.LOOKUP_TYPE='SRM_RESOURCE_TYPE'
                              AND NLS.TABLE_NAME='CMN_LOOKUPS'
                              AND NLS.LANGUAGE_CODE='en'
                         ) lk
                    WHERE r.id=o.id
                    AND r1.user_id(+)=r.manager_id
                    AND r.user_id=usr_grp.user_id
                    AND usr_grp.GROUP_ID=grp.id
                    AND r.person_type=lk.id
                    AND r.is_active = 1
                    AND r1.is_active = 1
                    AND grp.GROUP_CODE='gs_tb'
                    AND tp.prisopen = 1
               ) avail
               ,(     SELECT
                         r.id
                         ,tp.prid
                         ,SUM(NVL(practsum,0)/3600) act_hours
                         ,ts.prstatus timesheet_status
                    FROM
                         niku.SRM_RESOURCES r
                         ,niku.PRTIMESHEET ts
                         ,(      SELECT /*+ALL_ROWS*/
                                   MAX(prid) prid
                                   ,prtimeperiodid
                                   ,prresourceid
                              FROM
                                   niku.prtimesheet
                              GROUP BY
                                   prtimeperiodid,
                                   prresourceid
                         ) ts_new
                         ,niku.PRTIMEENTRY te
                         ,niku.PRTIMEPERIOD tp
                         ,niku.CMN_SEC_USER_GROUPS usr_grp
                         ,niku.CMN_SEC_GROUPS grp
                    WHERE
                         ts.prid=ts_new.prid
                    AND ts.prtimeperiodid=ts_new.prtimeperiodid
                    AND ts.prresourceid=ts_new.prresourceid
                    AND r.id=ts.PRRESOURCEID
                    AND ts.PRID=te.PRTIMESHEETID
                    AND ts.PRTIMEPERIODID=tp.prid
                    AND usr_grp.USER_ID=r.USER_ID
                    AND grp.id=usr_grp.group_id
                    AND r.is_active=1
                    AND tp.PRISOPEN=1
                    AND ts.prstatus not in(0,2,5)
                    AND grp.group_code='gs_tb'
                    AND TRUNC(tp.PRSTART) >= TRUNC(TO_DATE('7/24/2006','MM/DD/YYYY HH:MI:SS AM'))
                    AND TRUNC(tp.PRFINISH-1) <= TRUNC(TO_DATE('9/25/2006','MM/DD/YYYY HH:MI:SS AM'))
                    GROUP BY r.ID
                    ,tp.PRID
                         ,ts.prstatus
               ) act
          WHERE act.id(+) = avail.res_id
          AND act.prid(+) = avail.prid
          AND (avail.avail_hours - NVL(act.act_hours,0) > 0)
     )temp21
     ,prj_obs_associations o1
     ,nbi_dim_obs f
WHERE 1=1
     AND temp21.prid in (     SELECT prid
                                   FROM PRTIMEPERIOD
                                   WHERE TRUNC(PRSTART) >= TRUNC(TO_DATE('7/24/2006','MM/DD/YYYY HH:MI:SS AM'))
                                   AND TRUNC(PRFINISH-1) <= TRUNC(TO_DATE('9/25/2006','MM/DD/YYYY HH:MI:SS AM'))
AND
     temp21.res_id = o1.record_id
     AND o1.unit_id = f.obs_unit_id
     AND o1.table_name = 'SRM_RESOURCES'
     AND f.obs_type_id = 5000009
     AND f.level5_unit_id = 5013334
ORDER BY temp21.manager_name
,temp21.manager_id
,temp21.resource_name
,temp21.resource_code
,temp21.period_start
,temp21.period_finish
,temp21.timesheet_status Message was edited by:
david_tyler