Query execution slow

Question

Hi Experts,
I have problem with query execution. It is taking more time to execution.
Query is like this :
SELECT   gcc_po.segment1 bc,
         gcc_po.segment2 rc,
         gcc_po.segment3 dept,
         gcc_po.segment4 ACCOUNT,
         gcc_po.segment5 product,
         gcc_po.segment6 project,
         gcc_po.segment7 tbd,
         SUBSTR (pv.vendor_name, 1, 50) vendor_name,
         pv.vendor_id,
         NVL (ph.closed_code, 'OPEN') status,
         ph.cancel_flag,
         ph.vendor_site_id,
         ph.segment1 po_number,
         ph.creation_date po_creation_date,
         pv.segment1 supplier_number,
         pvsa.vendor_site_code,
         ph.currency_code po_curr_code,
         ph.blanket_total_amount,
         NVL (ph.rate, 1) po_rate,
         SUM (DECODE (:p_currency,
                      'FUNCTIONAL', DECODE (:p_func_curr_code,
                                            ph.currency_code, NVL
                                                            (pd.amount_billed,
                                                             0),
                                              NVL (pd.amount_billed, 0)
                                            * NVL (ph.rate, 1)
                      NVL (pd.amount_billed, 0)
                     )) amt_vouchered,
         ph.po_header_id poheaderid,
         INITCAP (ph.attribute1) po_type,
         DECODE (ph.attribute8,
                 'ARIBA', DECODE (ph.attribute4,
                                  NULL, ph.attribute4,
                                  ppf.full_name
                 ph.attribute4
                ) origanator,
         ph.attribute8 phv_attribute8,
         UPPER (ph.attribute4) phv_attribute4
    FROM po_headers ph,
         po_vendors pv,
         po_vendor_sites pvsa,
         po_distributions pd,
         gl_code_combinations gcc_po,
         per_all_people_f ppf
   WHERE ph.segment1 BETWEEN '001002' AND 'IND900714'
     AND ph.vendor_id = pv.vendor_id(+)
     AND ph.vendor_site_id = pvsa.vendor_site_id
     AND ph.po_header_id = pd.po_header_id
     AND gcc_po.code_combination_id = pd.code_combination_id
     AND pv.vendor_id = pvsa.vendor_id
     AND UPPER (ph.attribute4) = ppf.attribute2(+) -- no  index on attributes
     AND ph.creation_date BETWEEN ppf.effective_start_date(+) AND ppf.effective_end_date(+)
GROUP BY gcc_po.segment1,-- no index on segments
         gcc_po.segment2,
         gcc_po.segment3,
         gcc_po.segment4,
         gcc_po.segment5,
         gcc_po.segment6,
         gcc_po.segment7,
         SUBSTR (pv.vendor_name, 1, 50),
         pv.vendor_id,
         NVL (ph.closed_code, 'OPEN'),
         ph.cancel_flag,
         ph.vendor_site_id,
         ph.segment1,
         ph.creation_date,
         pvsa.attribute7,
         pv.segment1,
         pvsa.vendor_site_code,
         ph.currency_code,
         ph.blanket_total_amount,
         NVL (ph.rate, 1),
         ph.po_header_id,
         INITCAP (ph.attribute1),
         DECODE (ph.attribute8,
                 'ARIBA', DECODE (ph.attribute4,
                                  NULL, ph.attribute4,
                                  ppf.full_name
                 ph.attribute4
         ph.attribute8,
         ph.attribute4Here with out SUM funciton and group by function its execution is fast. if i use this Sum function and Group by function it is taking nearly 45 mins.
Explain plan for this:
Operation     Object Name     Rows     Bytes     Cost     Object Node     In/Out     PStart     PStop
SELECT STATEMENT Optimizer Mode=ALL_ROWS          1             6364                              
  HASH GROUP BY          1       272       6364                              
    NESTED LOOPS OUTER          1       272       6363                              
      NESTED LOOPS          1       232       6360                              
        NESTED LOOPS          1       192       6358                              
          NESTED LOOPS          1       171       6341                              
            HASH JOIN          1 K     100 K     2455                              
              TABLE ACCESS FULL     PO_VENDOR_SITES_ALL     1 K     36 K     1683                              
              TABLE ACCESS FULL     PO_VENDORS     56 K     3 M     770                              
            TABLE ACCESS BY INDEX ROWID     PO_HEADERS_ALL     1       82       53                              
              INDEX RANGE SCAN     PO_HEADERS_N1     69             2                              
          TABLE ACCESS BY INDEX ROWID     PO_DISTRIBUTIONS_ALL     1       21       17                              
            INDEX RANGE SCAN     PO_DISTRIBUTIONS_N3     76             2                              
        TABLE ACCESS BY INDEX ROWID     GL_CODE_COMBINATIONS     1       40       2                              
          INDEX UNIQUE SCAN     GL_CODE_COMBINATIONS_U1     1             1                              
      TABLE ACCESS BY INDEX ROWID     PER_ALL_PEOPLE_F     1       40       3                              
        INDEX RANGE SCAN     PER_PEOPLE_F_ATT2     2             1                               plz giv me solution for this.....Whihc Hints shall i use in this query.....
thanks in ADV....

Answer 1

I have a feeling this will lead us nowhere, but let me try for the last time.
Tuning a query is not about trying out all available index hints, because there must be one that makes the query fly. It is about diagnosing the query. See what it does and see where time is being spent. Only after you know where time is being spent, then you can effectively do something about it (if it is not tuned already).
So please read about explain plan, SQL*Trace and tkprof, and start diagnosing where your problem is.
Regards,
Rob.