Issue with sys_refcursor in oracle 10.2.0.4.0

Question

hi,
java is front end application and they want result set to be returned from oracle plsql, for simplicity i am writing code something like below.
create or replace function fun () retrun sys_refcursor is
tablename_cur sys_Refcursor;
begin
open tablename_cur for select statement;
return tablename_cur ;
end;
its all looks good.. but my client IT person questioned me about not closing cursor..
i feel it is good way of doing, not closing this type of cursor variable is fine i.e. tablename_cur in this case, does it cause any issues otherwise.. since i am about write not less 300+ such functions and would like to know on this if this is right practice or would it cuase any increase of opened cursor and never closed,.... therafter any performance issues..
or any other good practive to perform the same task. .. please suggest..
thanks in advance...

Answer 1

knowledgespring wrote:
I assume once sys_Refcursor returned all the rows it get closed automatically... i.e. fetched all the rows from it closes the sys_refcursor.. otherwise provide info.
according to you, does it mean if they close result set they use in java would result close of sys_refcursor!!.. not before.. may be somthing like
ResultSet rs = call oracle function which uses sys_refcursor
rs.close --> does it close sys_refcursor .. (would it open till then??!!!)..
java developers says we call functions written in oracle... and resultset to be returned.. (They are different team)..I don't know java, but it's correct, the consumer of the cursor is responsible for closing it.
e.g.
SQL> ed
Wrote file afiedt.buf
  1  create or replace function test_rc return sys_refcursor is
  2    v_rc sys_refcursor;
  3  begin
  4    open v_rc for 'select * from emp';
  5    return v_rc;
  6* end;
SQL> /
Function created.
SQL> var x refcursor;
SQL> exec :x := test_rc();
PL/SQL procedure successfully completed.
SQL> print x;
     EMPNO ENAME      JOB              MGR HIREDATE          SAL       COMM     DEPTNO
      7369 SMITH      CLERK           7902 17/12/1980        800                    20
      7499 ALLEN      SALESMAN        7698 20/02/1981       1600        300         30
      7521 WARD       SALESMAN        7698 22/02/1981       1250        500         30
      7566 JONES      MANAGER         7839 02/04/1981       2975                    20
      7654 MARTIN     SALESMAN        7698 28/09/1981       1250       1400         30
      7698 BLAKE      MANAGER         7839 01/05/1981       2850                    30
      7782 CLARK      MANAGER         7839 09/06/1981       2450                    10
      7788 SCOTT      ANALYST         7566 19/04/1987       3000                    20
      7839 KING       PRESIDENT            17/11/1981       5000                    10
      7844 TURNER     SALESMAN        7698 08/09/1981       1500          0         30
      7876 ADAMS      CLERK           7788 23/05/1987       1100                    20
      7900 JAMES      CLERK           7698 03/12/1981        950                    30
      7902 FORD       ANALYST         7566 03/12/1981       3000                    20
      7934 MILLER     CLERK           7782 23/01/1982       1300                    10
14 rows selected.Here, the "print" command of SQL*Plus uses the returned ref cursor to fetch the data back from the database, and when it's done it (behind the scenes) closes the cursor.
Oracle can't keep track (or even possibly know) of whether a client consumer of a ref cursor has finished fetching the records. Just because all the records may have been fetched, the cursor itself remains open until closed as it contains information about the state of the cursor e.g. whether there is more data to fetch or not.
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