Long running statement including function

Question

Hello expert,
I have a long running statement and corresponding function as follows:
select
pp.policy_premium_pk,
pp.policy_fk,
pp.policy_term_fk,
pp.risk_fk,
pp.coverage_fk,
pp.transaction_log_fk,
pp.coverage_component_code,
hiroc_rpt_user.hiroc_get_delta_amount(pp.policy_fk, pp.policy_term_fk, pp.risk_fk, pp.coverage_fk, pp.transaction_log_fk, pp.coverage_component_code),
pp.rate_period_from_date
from proddw_mart.rmv_policy_premium pp
where pp.rate_period_type_code = 'TERM_COVG'
and pp.coverage_component_code <> 'NETPREM'
-- and pp.premium_amount <> 0
-- *** Following line is included for faster performance
and hiroc_rpt_user.hiroc_get_delta_amount(pp.policy_fk, pp.policy_term_fk, pp.risk_fk, pp.coverage_fk, pp.transaction_log_fk, pp.coverage_component_code) != 0
group by pp.policy_premium_pk,
pp.policy_premium_pk,
pp.policy_fk,
pp.policy_term_fk,
pp.risk_fk,
pp.coverage_fk,
pp.transaction_log_fk,
pp.coverage_component_code,
pp.rate_period_from_date;
CREATE OR REPLACE FUNCTION HIROC_RPT_USER."HIROC_GET_DELTA_AMOUNT" (
p_policy_fk IN NUMBER,
p_policy_term_history_fk IN NUMBER,
p_risk_fk IN NUMBER,
p_coverage_fk IN NUMBER,
p_transaction_log_fk IN NUMBER,
p_comp_code IN VARCHAR2)
RETURN NUMBER
IS
v_prev_trlog_fk NUMBER;
v_delta NUMBER;
v_parm VARCHAR2(1000);
v_msg VARCHAR2(200);
comma VARCHAR2(1) := ',';
v_src VARCHAR2(100) := 'Get_Delta_Amount';
BEGIN
SELECT nvl(MAX(pp.transaction_log_fk), -1)
INTO v_prev_trlog_fk
FROM proddw_mart.rmv_Policy_Premium pp
WHERE pp.coverage_fk = p_coverage_fk
AND pp.policy_term_fk = p_policy_term_history_fk
AND pp.transaction_log_fk+0 < p_transaction_log_fk
AND pp.coverage_component_code = p_comp_code
AND pp.rate_period_type_code = 'TERM_COVG';
SELECT nvl(SUM(decode(pp.transaction_log_fk, p_transaction_log_fk, premium_amount, 0)), 0) -
nvl(SUM(decode(pp.transaction_log_fk, p_transaction_log_fk, 0, pp.premium_amount)), 0)
INTO v_delta
FROM proddw_mart.rmv_Policy_Premium pp
WHERE pp.coverage_fk = p_coverage_fk
AND pp.policy_term_fk = p_policy_term_history_fk
AND pp.transaction_log_fk+0 IN (p_transaction_log_fk, v_prev_trlog_fk)
AND pp.rate_period_type_code = 'TERM_COVG'
AND INSTR(p_comp_code, pp.coverage_component_code) > 0;
RETURN v_delta;
EXCEPTION
WHEN NO_DATA_FOUND THEN
return 0;
WHEN OTHERS THEN
return 0;
END;
and it execution plan is as follows:
PLAN_TABLE_OUTPUT
Plan hash value: 319541564
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 92525 | 5511K| | 17417 (4)| 00:03:30 |
| 1 | HASH GROUP BY | | 92525 | 5511K| 14M| 17417 (4)| 00:03:30 |
|* 2 | MAT_VIEW ACCESS FULL| RMV_POLICY_PREMIUM | 92525 | 5511K| | 16045 (4)| 00:03:13 |
Predicate Information (identified by operation id):
2 - filter("PP"."RATE_PERIOD_TYPE_CODE"='TERM_COVG' AND
"PP"."COVERAGE_COMPONENT_CODE"<>'NETPREM' AND
"HIROC_RPT_USER"."HIROC_GET_DELTA_AMOUNT"("PP"."POLICY_FK","PP"."POLICY_TERM_FK","PP"."RISK_
FK","PP"."COVERAGE_FK","PP"."TRANSACTION_LOG_FK","PP"."COVERAGE_COMPONENT_CODE")<>0)

Answer 1

As the first (warming up) step you could rewrite your function to do it's task with a single select
CREATE OR REPLACE FUNCTION
HIROC_RPT_USER."HIROC_GET_DELTA_AMOUNT" (p_policy_fk IN NUMBER,  /* not used */
                                         p_policy_term_history_fk IN NUMBER,
                                         p_risk_fk IN NUMBER,    /* not used */
                                         p_coverage_fk IN NUMBER,
                                         p_transaction_log_fk IN NUMBER,
                                         p_comp_code IN VARCHAR2
  RETURN NUMBER
  IS
  v_prev_trlog_fk NUMBER;
  v_delta NUMBER;
BEGIN
  SELECT nvl(MAX(pp.transaction_log_fk), -1)
    INTO v_prev_trlog_fk
    FROM proddw_mart.rmv_Policy_Premium pp
   WHERE pp.coverage_fk = p_coverage_fk
     AND pp.policy_term_fk = p_policy_term_history_fk
     AND pp.transaction_log_fk+0 < p_transaction_log_fk
     AND pp.coverage_component_code = p_comp_code
     AND pp.rate_period_type_code = 'TERM_COVG';
  SELECT nvl(SUM(decode(pp.transaction_log_fk, p_transaction_log_fk, premium_amount, 0)), 0) -
         nvl(SUM(decode(pp.transaction_log_fk, p_transaction_log_fk, 0, pp.premium_amount)), 0)
    INTO v_delta
    FROM proddw_mart.rmv_Policy_Premium pp
   WHERE pp.coverage_fk = p_coverage_fk
     AND pp.policy_term_fk = p_policy_term_history_fk
     AND pp.transaction_log_fk+0 IN (p_transaction_log_fk, v_prev_trlog_fk)
     AND pp.rate_period_type_code = 'TERM_COVG'
     AND INSTR(p_comp_code, pp.coverage_component_code) > 0;
  select nvl(sum(case transaction_log_fk when p_transaction_log_fk
                                         then premium_amount
                                         else -premium_amount
                 end
             0
    into v_delta
    from proddw_mart.rmv_Policy_Premium
   where coverage_fk = p_coverage_fk
     and policy_term_fk = p_policy_term_history_fk
     and instr(p_comp_code,coverage_component_code) > 0
     and rate_period_type_code = 'TERM_COVG'
     and transaction_log_fk in (select p_transaction_log_fk,nvl(max(transaction_log_fk),-1)
                                   from proddw_mart.rmv_Policy_Premium
                                  where coverage_fk = p_coverage_fk
                                    and policy_term_fk = p_policy_term_history_fk
                                    and transaction_log_fk < p_transaction_log_fk
                                    and coverage_component_code = p_comp_code
                                    and rate_period_type_code = 'TERM_COVG'
  RETURN v_delta;
EXCEPTION
  WHEN NO_DATA_FOUND THEN return 0;
  WHEN OTHERS THEN return 0;
END;in the next step you could get rid of the function call:
something along the lines of
select pp.policy_premium_pk,
       pp.policy_fk,
       pp.policy_term_fk,
       pp.risk_fk,
       pp.coverage_fk,
       pp.transaction_log_fk,
       pp.coverage_component_code,
       nvl(sum(case f.transaction_log_fk when pp.transaction_log_fk
                                         then f.premium_amount
                                         else -f.premium_amount
               end
           0
          ) premium_amount,
       pp.rate_period_from_date
  from proddw_mart.rmv_policy_premium pp,
       (select p.premium_amount,
               p.policy_term_fk,
               p.coverage_fk,
               p.transaction_log_fk,
               p.coverage_component_code
          from proddw_mart.rmv_Policy_Premium p
         where p.rate_period_type_code = 'TERM_COVG'
           and instr('NETPREM',coverage_component_code) > 0
       ) f
where pp.rate_period_type_code = 'TERM_COVG'
   and pp.coverage_component_code = 'NETPREM'
   and pp.policy_term_fk = f.policy_term_fk
   and pp.coverage_fk = f.coverage_fk
   and (
        pp.transaction_log_fk = f.transaction_log_fk
    or
        pp.transaction_log_fk = (select nvl(max(transaction_log_fk),-1)
                                   from proddw_mart.rmv_Policy_Premium
                                  where rate_period_type_code = 'TERM_COVG'
                                    and coverage_component_code = 'NETPREM'
                                    and policy_term_fk = pp.policy_term_fk
                                    and coverage_fk = pp.coverage_fk
                                    and transaction_log_fk < pp.transaction_log_fk
group by pp.policy_premium_pk,
          pp.policy_premium_pk,
          pp.policy_fk,
          pp.policy_term_fk,
          pp.risk_fk,
          pp.coverage_fk,
          pp.transaction_log_fk,
          pp.coverage_component_code,
          pp.rate_period_from_dateRegards
Etbin