Memory of jdbc app grows over time (timesten backend db)

Question

Hi everyone,
I have a memory problem with my application(timesten backend db). I don't know how to resolve it and need your help.
When I call stored procedures with CallableStatement, the resident memory of application grows over time (up to 6GB).
I closed statement after executing.
Below is my code and the stored procedure.
public boolean check(String sub)
CallableStatement cs = null;
int result = 0;
try
cs = conn.prepareCall("begin pr_check_sub(:1,:2); end;");
cs.setQueryTimeout(30);
cs.setString(2, sub);
cs.registerOutParameter(1, java.sql.Types.INTEGER);
cs.execute();
result = cs.getInt(1);
cs.clearParameters();
System.out.println(msisdn + "----" + result);
catch (SQLException ex)
ex.printStackTrace();
catch (Exception ex)
ex.printStackTrace();
finally
try
if (cs != null)
cs.close();
catch (SQLException ex)
ex.printStackTrace();
return (result == 1 ? true : false);
create or replace PROCEDURE pr_check_sub
(RESULT OUT NUMBER,SUBNUMBER IN VARCHAR2)
IS
BEGIN
BEGIN
RESULT:=0;
SELECT COUNT(*) INTO RESULT FROM tbl_test
WHERE sub=SUBNUMBER;
IF(RESULT >= 1) THEN
RESULT:=1;
END IF;
EXCEPTION
WHEN OTHERS THEN
RESULT:=0;
END;
END;
Thank you!
Edited by: user5175632 on Oct 25, 2011 3:35 AM

Answer 1

This might be due to this bug raised for JDBC Client/Server connection
Bug 12969330 : MEMORY LEAK IN JDBC CS FOR CALLABLE/PREP STATEMENT W/ NUMPARM % 4 != 0
There is a leak in JDBC driver which seems to affect only C/S; it does not seem to affect direct or batch. ** This bug has been there since 11.2.1.6.0.
Here are few conditions which are needed for this bug to occur:
1. Application must be using a Client/server connection
2. Applications repeatedly does the following:
1. Create a PreparedStatement or CallableStatement
2. set or register IN, OUT or IN OUT parameters
3. Number of parameters is not an integral multiple of 4. It is the total number of parameters which matter; parameter type does not matter. JDBC driver leaks memory if the number of parameters in a PreparedStatement/CallableStatement are not an integral multiple of 4.
3. On a close 1-3 parameters can be leaked.
If your application deals with above scenario then there is a possible chance of the bug being hit. An example of a scenario :-
The below PreparedStatement has 1 parameter (so it's not an integral multiple of 4):
preparedStatement = connection.prepareStatement("SELECT col1 FROM Tab1 WHERE col2 = ? "); <===== Possible memory leak here
To workaround the bug, you can add 3 dummy parameters -- SELECT col1 FROM Tab1WHERE col2 = ? and 1=? and 1=? and 1=? and set parameters 2,3 and 4 to 1.
preparedStatement = connection.prepareStatement("SELECT col1 FROM Tab1WHERE col2 = ? and 1=? and 1=? and 1=? ");
I've seen this bug a couple of times now. I don't think there is a release yet which includes a fix.