Different query behaviour (index or no index use) between sql and pl/sql

Question

Hi All,
I have a query inside a cursor in a procedure, let's say:
cursor c_emp (b_dept_no in number)
is
select *
from emp
where dept_no = b_dep_no;
There is an non unique index on dept_no.
In this procedure i first loop through another cursor which gets the dept_no and with this dept_no i go into a for loop for the c_emp cursor.
When i run this procedure i see that the explain plan of above query gives me a Full table Scan on EMP, eventhough there is a index on dept_no and there are 1.3 million records in the em table. When i take the above query and explain it seperately, it uses the index on dept_no.
I have rebuild/analyzed the tables and indexes, nothing seems to work. Even hints in the procedure cursor are not helping at all.
I'm using Oracle Database 10.2.0.1.0 and have never seen such behaviour before.
Anyone an idea what is going on here?
Kind regards,
Dave

Answer 1

Hoi Rob,
it's like i have three tables. The first i have to get data from for my output, then for every record of table one there are one or more records in table 2 and table 3.
I had to create a xml file and it looks like this:
<Table1 Record 1>
<Name>...</Name>
etc...
<Table2 Record 1>
</Table2 Record 1>
<Table2 Record 2>
</Table2 Record 2>
<Table3 Record 1>
</Table3 Record 1>
<Table3 Record 2>
</Table3 Record 2>
<Table1 Record 2>
etc.etc.etc.
So that's why i programmed:
for r_1 in c_table1 loop
for r_2 in c_table2(r_1.dept_no) loop
end loop;
for r_3 in c_table3(r_1.dept_no) loop
end loop;
end loop;
And when i look at the first record,
it has 2 records in table2 en 16 records in table3. So nothing huge.
For now i'm unable to trace the session. I will try to post the tkprof later.
Kind regards,
Dave