arrays in pl sql | varray | associative - oracle

Question

I'm planning to write a pl sql
pseudo code
procedure a gets all records from emp and is passed to procedure b
procedure b getting called inside from a , is transforming the data from emp , each emp record is traversed 6 times and storing the data in an array
inside procedure b , i used varray (size of 2000 to 2 mil) and also associative array , but it is always failing after handling 10 -15 records .i.e. after handling it for 60 -90 records
i am reusing the same index for storing my data but nothing worked i.e. 1 to 6
I am not sure what i am doing wrong , please assist .
create or replace PROCEDURE query_emp ( bill_cycle_ip in number,
no_of_recs in number ) AS
TYPE billAcnt IS REF CURSOR RETURN emp%ROWTYPE;
ba_rec emp%ROWTYPE;
b_a billAcnt;
total_num_of_rec number ;
BEGIN
OPEN b_a FOR
select * from
(select * from emp where bill_cycle =1 and ban_status in ('O' ,'S')
union
select * from emp where bill_cycle =1 and ban_status in ('N')
and STATUS_LAST_DATE >= sysdate -30
)
where ban not in (Select ban from temp_ba)
and rownum <no_of_recs;
LOOP
FETCH b_a INTO ba_rec;
EXIT WHEN b_a%NOTFOUND;
create_final_snapshot (ba_rec);
END LOOP;
CLOSE b_a;
END;
create or replace procedure create_final_snapshot ( ba_rec IN emp%ROWTYPE ) AS
cur_bl_seq_number number ;
bl_seq_number_minus_six number ;
type total_due_amt is table of number INDEX BY PLS_INTEGER ;
nt total_due_amt := total_due_amt();
b number := 1 ;
BEGIN
cur_bl_seq_number :=ba_rec.BL_CUR_BILL_SEQ_NO ;
if ba_rec.BL_CUR_BILL_SEQ_NO-5 <=1 then
bl_seq_number_minus_six:=1;
else
bl_seq_number_minus_six:=ba_rec.BL_CUR_BILL_SEQ_NO-5;
end if ;
for a in bl_seq_number_minus_six..cur_bl_seq_number
LOOP
--nt.extend();
select xyz into nt(b) from emp_2 where ban =ba_rec.ban and bill_seq_no =a ;
dbms_output.put_line('total_due_amt_list sun= ' ||ba_rec.ban ||' ' || nt(b) || ' bill seq no ' ||a ||' b ' || b );
b := b +1;
END loop;
b:=1;
insert into temp_ba
values (nt(1) ,nt(2), nt(3),nt(4),nt(5),nt(6) );
END;