plsql procedure talking forever to run - sql

Question

This Procedure is compiling fine but taking forever to run. I think even for single row, it is taking too much time to process. Where should I change the code to make it run faster?
CREATE OR REPLACE PROCEDURE NEWWAPTWOPROC(
P_WAP NUMBER,
P_DEALNO VARCHAR2,
P_FDT DATE,
P_SECURITYCD VARCHAR2,
P_SECURITYTYPE VARCHAR2,
P_SELFORCONSTITUENT VARCHAR2
)
IS
v_pofv NUMBER(30);
v_sofv NUMBER(30);
CURSOR C1 IS
SELECT
D.SECURITYCD SCD,
D.DEALNO DNO,
S.OWNSTK OWNST,
LAG(S.OWNSTK) OVER(ORDER BY D.DEALDT) PC_STK,
D.Dealtype DTYPE,
D.SECURITYTYPE STYPE,
D.SELFORCONSTITUENT SFORCO,
D.DEALDT DDATE ,
D.PRICE PRC,
D.FACEVALUE FV,
LAG(D.FACEVALUE) OVER(ORDER BY D.DEALDT) PC_FV,
D.WAP1 WP,
LAG(D.WAP1) OVER(ORDER BY D.DEALDT) PC_WAP1
FROM MMDEAL0_NWAP D INNER JOIN Mmstock1 S
ON D.Securitycd=S.Securitycd
WHERE D.DEALDT>=P_FDT
AND D.DEALNO=P_Dealno
AND D.FACEVALUE>0
AND D.Dealtype IN('PO','SO')
AND D.Selforconstituent='S'
AND D.SECURITYTYPE='DGS'
ORDER BY
D.DEALDT,D.Securitycd;
BEGIN
FOR i in C1
LOOP
if C1%rowcount=1 then
UPDATE MMDEAL0_NWAP SET WAP1=P_WAP WHERE Dealno=P_DEALNO AND DEALDT=P_FDT AND
SECURITYCD=P_SECURITYCD AND SECURITYTYPE=P_SECURITYTYPE AND
Selforconstituent=P_SELFORCONSTITUENT;
else
IF i.OWNST>0 then
if i.DTYPE='PO' then
v_pofv:=i.FV;
elsif i.DTYPE='SO' then
v_sofv:=i.FV;
end if;
i.WP:=((nvl(i.PC_WAP1,0)*nvl(i.PC_STK,0))+(nvl(v_pofv,0)*nvl(i.PRC,0)))-(nvl(v_sofv,0)*nvl(i.PC_WAP1,0))/i.OWNST;
UPDATE MMDEAL0_NWAP SET WAP1=i.WP WHERE DEALNO=i.DNO AND DEALDT=i.DDATE AND
SECURITYCD=i.SCD AND SECURITYTYPE=i.STYPE AND SELFORCONSTITUENT= i.SFORCO;
END IF;
end if;
END LOOP;
EXCEPTION
WHEN OTHERS THEN
Dbms_Output.Put_Line(SQLCODE||' '||SQLERRM);
END NEWWAPTWOPROC;

Answer 1

You are using CURSOR and loops for no reason when all your updates can be converted to an update and a MERGE statement.
This below is your update statement for the case C1%rowcount=1, which was not required to be put inside the loop even before.
UPDATE mmdeal0_nwap
SET wap1 = p_wap
WHERE dealno = p_dealno
AND dealdt = p_fdt
AND securitycd = p_securitycd
AND securitytype = p_securitytype
AND selforconstituent = p_selforconstituent;
The second update converted to MERGE
MERGE INTO mmdeal0_nwap t USING (
SELECT i.*,
( ( nvl(i.pc_wap1,0) * nvl(i.pc_stk,0) ) + ( nvl(v_pofv,0) * nvl(i.prc,0) ) ) - ( nvl(v_sofv
,0) * nvl(i.pc_wap1,0) ) / i.ownst AS new_wp --your calculation for the value of WP to be updated
FROM (
SELECT d.securitycd scd,
d.dealno dno,
s.ownstk ownst,
LAG(s.ownstk) OVER(
ORDER BY d.dealdt
) pc_stk,
d.dealtype dtype,
d.securitytype stype,
d.selforconstituent sforco,
d.dealdt ddate,
d.price prc,
d.facevalue fv,
LAG(d.facevalue) OVER(
ORDER BY d.dealdt
) pc_fv,
d.wap1 wp,
LAG(d.wap1) OVER(
ORDER BY d.dealdt
) pc_wap1,
CASE
WHEN d.dealtype = 'PO' THEN d.facevalue
END
AS v_pofv,
CASE
WHEN d.dealtype = 'SO' THEN d.facevalue -- IF conditions converted to CASE
END
AS v_sofv
FROM mmdeal0_nwap d
INNER JOIN mmstock1 s ON d.securitycd = s.securitycd
WHERE d.dealdt >= p_fdt AND d.dealno = p_dealno AND d.facevalue > 0 AND d.dealtype IN (
'PO',
'SO'
) AND d.selforconstituent = 'S' AND d.securitytype = 'DGS'
) i
WHERE i.ownst > 0 --outer IF condition
)
ON (
t.dealno = s.dno AND t.dealdt = s.ddate AND t.securitycd = s.scd AND t.securitytype = s.stype AND
t.selforconstituent = s.sforco
) --where clause from your update
WHEN MATCHED THEN UPDATE SET t.wap1 = s.new_wp;
Please note that the code is untested, so you may have to fix some syntactic errors / editing mistakes which I may have made. But, I believe I have given you fair enough idea how to proceed.

Answer 2

Some general suggestions for investigating PL/SQL performance:
Add dbms_output messages containing counts and timings (or write the details to a log table). This may be tricky if the code never completes or produces too much output, but you may be able to create some simplified test data to limit the run.
Step through the code in the debugger until you can identify the issue, for example if some value is not being reset as expected or a loop is not being exited. It will also give you a feel for how long each step takes. (Desktop tools have different ways to launch the debugger, but they should all provide the feature.)
Use dbms_profiler to get a report on how many times each statement is called and much time is spent on it. Again you may need to restrict the run with simplified test data. Profiling is built into some desktop tools such as PL/SQL Developer so you can just click a button, or else it's straightforward to use on the command line. (There is also dbms_hprof, although it's more complicated to use for little benefit, and dbms_trace, although in my experience this doesn't tell you anything useful.)
You can tell a lot about what it is doing by querying v$session from another session. Some desktop tools have session monitors built in to make this easier.
If you have licenced the Diagnostics and Tuning Pack, you can get a lot of useful run-time information out of v$active_session_history.
You can monitor running or recently completed SQL with SQL Monitor. If you have access to it, Oracle Enterprise Manager / Cloud Control gives you a lot of this via a convenient browser based dashboard. I would also take each SQL statement and test it on the command line to make sure it did what I expected and completed in a reasonable time.