Memory Leak in 8.1.6.0.1 JDBC/OCI for Solaris

Question

Hello,
there is a memory leak in the 8.1.6.0.1 JDBC-OCI driver for solaris.
The leak causes your jvm to eat up all memory
if you reuse callable statements
(calling one statement multiple times with
different values).
The thin driver has no such problem. Is
there any fix available ?

Answer 1

Ok. The code spans multiple classes and
most of it comes from a customized version
of the Enhydra Java Application server.
I have a class called "StandardDBConnection"
which caches CallableStatements and is a
wrapperclass for java.sql.DBConnection. The
interesting method here is "prepareCall":
* Get a callable statement given an SQL string. If the statement is
* cached, return that statement, otherwise prepare and save in the
* cache.
* @param sql The SQL statement to be called.
* @return a new CallableStatement object containing the
* pre-compiled SQL statement.
* @exception java.sql.SQLException If a database access error occurs
* statement.
public synchronized CallableStatement prepareCall(String sql)
throws SQLException {
PreparedStatement preparedStmt;
logDebug ("Prepare call: " + sql);
validate();
preparedStmt = (PreparedStatement)preparedStmtCache.get(sql);
// Check if the object returned by the cache really is a
// callable statement. if it is not, someone did call first
// prepareStatement() and now prepareCall() with the same
// sql. Silently replace the existing cache entry by a
// callable statement in this case.
if (preparedStmt instanceof CallableStatement) {
preparedStmt.clearParameters();
else {
// Need to close the old PreparedStatement in case we have to
// replace it with a CallableStatement
if (preparedStmt != null) {
preparedStmt.close();
else if (preparedStmtCache.size() >= maxPreparedStmts) {
String key = (String)preparedStmtCache.keys().nextElement();
((PreparedStatement) preparedStmtCache.remove(key)).close();
preparedStmt = connection.prepareCall(sql);
preparedStmtCache.put(sql, preparedStmt);
return (CallableStatement)preparedStmt;
The statements get closed when I close the
connection:
boolean closeStmts = true;
// Close the prepared statements.
Enumeration e = preparedStmtCache.keys();
while (e.hasMoreElements() && closeStmts) {
String key = (String)e.nextElement();
try {
((PreparedStatement)
preparedStmtCache.remove(key)).close();
} catch (SQLException except) {
// Ignore errors, we maybe handling one.
closeStmts = false;
log.write(Logger.NOTICE,
"DBConnection[" + id + "]: " + url +
"\nUnable to close statements. Continuing....\n");
In my classes using database queries I just
use the prepareCall method of DBConnection
and do not have to care about anything.
Works perfectly with the thin driver, but
as soon as I switch to oci... :-|
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JDBC Dev Team:
Soda, Rupper,
Do you mind posting some code that shows us what your code was doing when you notice this leak?
Thanks.<HR></BLOCKQUOTE>
null