How to Optimize this code?

Question

Hi All
I have a procedure which runs fine,but since the data in table XYZ,ABC runs into millions it becomes too slow..Can any one guide me in optimising the code.I have already created indexes on these columns.
CREATE OR REPLACE PROCEDURE test AS
    CURSOR c1 IS
        SELECT
            t.cutGrp,
            t.cutGrpCode,
            t.modelDesc,
            t.startdate,
            t.enddate,
            avg(t.price) price,
            avg(t.netprice) netprice,
            sum(t.awdQTY) awardqty,
            sum(t.planQTY) revplanqty,
        FROM
            ABC t
        GROUP BY
            t.cutGrp,
            t.cutGrpCode,
            t.modelDesc,
            t.startdate,
            t.enddate;
counter NUMBER := 0;
l_aggregate NUMBER;
BEGIN
     FOR rec IN c1
     LOOP
        counter := counter + 1;
        SELECT
            sum(t.anotherQTY) INTO l_aggregate
        FROM
             XYZ t
        WHERE
            t.cutstomer_Grp = rec.cutGrp
            AND t.cutGrp_Code = rec.cutGrpCode
            AND t.product_model = rec.modelDesc;
        UPDATE XYZ t
        SET
            t.testQTY = l_aggregate,
            t.testprice = rec.price,
            t.testnetprice = rec.netprice,
            t.testawardQTY = rec.awardqty,
            t.testplanQTY = rec.revplanqty,         
            t.fcstartdate = rec.startdate,
            t.fcenddate = rec.enddate
        WHERE
            t.cutstomer_Grp = rec.cutGrp
            AND t.cutGrp_Code = rec.cutGrpCode
            AND t.cutGrp_Code = rec.modelDesc;
    END LOOP;
    COMMIT WORK;
END test;
SHOW ERRORS;

Answer 1

Hi All
This the only query i could come up with...But this gives me error
ORA-30926 unable to get a stable set of rows in the source tables.Also this code does not address
SELECT
            sum(t.anotherQTY) INTO l_aggregate
        FROM
             XYZ t
        WHERE
            t.cutstomer_Grp = rec.cutGrp
            AND t.cutGrp_Code = rec.cutGrpCode
            AND t.product_model = rec.modelDesc;<b>This is what i came up with </b> so any code help is appreciated
MERGE INTO sgforecastrecord b
USING (
SELECT
     cutGrp
     cutGrpCode ,
     modelDesc,
     startdate,
     enddate,
     avg(price) price,
     avg(netprice) netprice,
     sum(awdQTY) awardqty,
     sum(planQTY) revplanqty     
FROM
      ABC
GROUP BY
     cutGrp,
     cutGrp,
     modelDesc,
     startdate,
     enddate
) t
on           (
     t.cutstomer_Grp = b.cutGrp
        AND t.cutGrp_Code = b.cutGrpCode
            AND t.product_model = b.modelDesc;
WHEN MATCHED THEN
     UPDATE  set 
          b.testprice = t.price,
           b.testnetprice = t.netprice,
            b.testawardQTY = t.awardqty,
            b.testplanQTY = t.revplanqty,         
            b.fcstartdate = t.startdate,
            b.fcenddate = t.enddate