Running out of data connections

Question

Problem Statement:
Running out of data connections after some time and
the following SQLException is thrown:
"failed to create a data connection with any of the
specified drivers"
Problem Description:
I have an application that is running under iPlanet
6.0 on solaris using Oracle 8 and type 2 Oracle
driver.
The application is using a number of stateless
session beans.
Normally, my servlets instantiate the remote beans in
order to make access to their interfaces. For
example, I have a servlet that fetches all of
the accounts for a given customer. First, The servlet
does the fetch by calling JNDI to lookup the "home"
interface, then does a "create" call on the home
interface to get the "remote" interface
(see snippets of code below, the ejbCreate()).
Second, the servlet calls up a specific method that
extracts the customer's accounts (see snippets of
code below, the method getAccountList()).
At first all seem to work well, however after some
random time my beans start to throw the SQLException
"failed to create a data connection with any of the
specified drivers"
At first I thought that I am not closing the
connections, but all of of my connections,
statements, and result sets, are closed
and even set to null in a finally block as you can
see in the snippets of code below.
If I restart iAS, all of the connections get released
and things look normal again till the problem
re-occurs.
Initially, we had this problem on SP2, so we upgraded
to SP3 thinking that this may solve the problem,
however the problem remained on SP3.
Another thing, this same application works perfectly
well on my laptop which has similar iPlanet
configurations except that operating system is
Windows 2000 Advanced Server, and Oracle 8.0.4.0.0.
System Configuration:
Following is my system configuration and related
iPlanet 6.0 settings.
-1- iPlanet 6.0 SP3
-2- Type 2 Oracle driver
-3- SunOs, sparc SUNW, Ultra-250, solaris 5.8
-4- Oracle 8.1.6.0.0 64-bit Production
-5- Following are the entry settings in the iPlanet
registry under
Software\iPlanet\Application Server\6.0\CCS0\DAE2\ORACLE_OCI
- CacheCleanInterval = 120
- CacheConnTimeOut = 120
- CacheDebugMsgs = 0
- CacheFreeSlots = 16
- CacheInitSlots = 64
- CacheMaxConn = 64
- CachMaxGlobalConn = 128
- ConnGiveUpTime = 60
- RMThreadMax = 32
- RMThreadMin = 0
- RSBufferInitRows = 25
- RSBufferMaxBufferSize = 6553600
- RSBufferMaxRows = 100
- RSBufferMaxSize = 32768
- SQLDebugMsgs = 0
Snippets of Code:
The following snippets of code come from a stateless
session bean and consist of a local data member, the
ejbCreate() method, and a typical rmi method that
does the database connection and extraction of
related records.
javax.sql.DataSource dataSourceObj = null;
public void ejbCreate()
throws java.rmi.RemoteException, javax.ejb.CreateException
javax.naming.Context ctx = null;
// Ensure first that the _props have been
// successfully instantiated by the constructor.
if (_props != null) {
try{
ctx = new javax.naming.InitialContext();
}catch (Exception ex){           
     nbUtility.logError(ex,"Error while creating Initial Context !");
try{
// DEBUG:
System.out.println("ejbCreate(): NB_DATASOURCE = " + props.getPropertyValue(props.NB_DATASOURCE));
// DEBUG:
     dataSourceObj = (javax.sql.DataSource) ctx.lookup(_props.getPropertyValue(_props.NB_DATASOURCE));
catch (Exception ex){
     ex.printStackTrace();
if (dataSourceObj == null)
throw new javax.ejb.CreateException("Couldn't get DataSource object from environment");
} else {
throw new javax.ejb.CreateException("Couldn't create the property manager: NB_CONFIG_FILE is null, empty, not set, or the file doesn't exist.");
* Given a customer number, this method
* returns the list of accounts that belongs to
* this customers.
public nbAccountList getAccountList(String CustomerNo)
throws java.rmi.RemoteException {
nbAccountList accountList = null;
if ((CustomerNo != null) && (!CustomerNo.equals(""))) {
java.sql.Connection conn = null;
java.sql.Statement stmt = null;
java.sql.ResultSet rset = null;
try {
accountList = new nbAccountList();
String sql = "SELECT * FROM " +
props.getPropertyValue(props.NB_DBTABLE_ACCOUNT) +
" WHERE " +
"(" + props.getPropertyValue(props.NB_DBFIELD_ACCOUNT_CUSTOMERNO) +
"='" + CustomerNo + "')";
// DEBUG:
nbDebug.write("accounts list SQL= " + sql);
// DEBUG:
// Let's get the connection, the statement, and the record set.
conn = dataSourceObj.getConnection();
stmt = conn.createStatement();
rset = stmt.executeQuery(sql);
// Let's loop for each single account
int index = 0;
nbAccount account = null;
while (rset.next()) {
     String AccountNo = rset.getString(_props.getPropertyValue(_props.NB_DBFIELD_ACCTPERMIS_ACCOUNTNO));
// Instantiate an account object
account = new nbAccount(AccountNo);
index++;
} catch (SQLException e) {
     nbUtility.logError(e, "SQLException while trying to get accounts data.");
} finally {
try {
if (rset != null) { rset.close(); rset = null; }      
if (stmt != null) { stmt.close(); stmt = null; }
if (conn != null) { conn.close(); conn = null; }
} catch (SQLException e) {
     nbUtility.logError(e, "SQLException while trying to close connection.");
return (accountList);      
}

Answer 1

I've experienced similar problems. Unfortunately, all efforts by iPlanet
technical support to resolve the issue have failed. (They do keep calling
and asking if they can close the ticket for some reason)
One thing that's totally anoying is the ksvradmin monitory crashes when I
try to have it report any connection pool information. They verified it's a
bug in SP3 but won't say if it's fixed in SP4 or provide an estimate.
To date here's what I've tried (by tech support's recomendation):
1) Configure for global transactions. (even thow I'm not using them)
(Failed)
2) Switch to using 3rd party driver (We were previously using native)
(Failed)
3) Ran report on oracle showing number of connections used during iplanet's
failed attempt. Report from Oracle shows 2 connections open, but iPlanet is
configured for 120.
4) Increased the connection pool size. (I didn't know why based on the
above info) (Increased to 300) (Failed)
Well there's my history. We crash after about 3 days of heavy usage. I'm
about to give up and just reset my servers each night. Will help me with
logfile rotation of the kjs files as well.
Rodger Ball
Sr. Engineer
Business Wire
"Bilal Chouman" <[email protected]> wrote in message
news:[email protected]...
Problem Statement:
Running out of data connections after some time and
the following SQLException is thrown:
"failed to create a data connection with any of the
specified drivers"
Problem Description:
I have an application that is running under iPlanet
6.0 on solaris using Oracle 8 and type 2 Oracle
driver.
The application is using a number of stateless
session beans.
Normally, my servlets instantiate the remote beans in
order to make access to their interfaces. For
example, I have a servlet that fetches all of
the accounts for a given customer. First, The servlet
does the fetch by calling JNDI to lookup the "home"
interface, then does a "create" call on the home
interface to get the "remote" interface
(see snippets of code below, the ejbCreate()).
Second, the servlet calls up a specific method that
extracts the customer's accounts (see snippets of
code below, the method getAccountList()).
At first all seem to work well, however after some
random time my beans start to throw the SQLException
"failed to create a data connection with any of the
specified drivers"
At first I thought that I am not closing the
connections, but all of of my connections,
statements, and result sets, are closed
and even set to null in a finally block as you can
see in the snippets of code below.
If I restart iAS, all of the connections get released
and things look normal again till the problem
re-occurs.
Initially, we had this problem on SP2, so we upgraded
to SP3 thinking that this may solve the problem,
however the problem remained on SP3.
Another thing, this same application works perfectly
well on my laptop which has similar iPlanet
configurations except that operating system is
Windows 2000 Advanced Server, and Oracle 8.0.4.0.0.
System Configuration:
Following is my system configuration and related
iPlanet 6.0 settings.
-1- iPlanet 6.0 SP3
-2- Type 2 Oracle driver
-3- SunOs, sparc SUNW, Ultra-250, solaris 5.8
-4- Oracle 8.1.6.0.0 64-bit Production
-5- Following are the entry settings in the iPlanet
registry under
Software\iPlanet\Application Server\6.0\CCS0\DAE2\ORACLE_OCI
- CacheCleanInterval = 120
- CacheConnTimeOut = 120
- CacheDebugMsgs = 0
- CacheFreeSlots = 16
- CacheInitSlots = 64
- CacheMaxConn = 64
- CachMaxGlobalConn = 128
- ConnGiveUpTime = 60
- RMThreadMax = 32
- RMThreadMin = 0
- RSBufferInitRows = 25
- RSBufferMaxBufferSize = 6553600
- RSBufferMaxRows = 100
- RSBufferMaxSize = 32768
- SQLDebugMsgs = 0
Snippets of Code:
The following snippets of code come from a stateless
session bean and consist of a local data member, the
ejbCreate() method, and a typical rmi method that
does the database connection and extraction of
related records.
javax.sql.DataSource dataSourceObj = null;
public void ejbCreate()
throws java.rmi.RemoteException, javax.ejb.CreateException
javax.naming.Context ctx = null;
// Ensure first that the _props have been
// successfully instantiated by the constructor.
if (_props != null) {
try{
ctx = new javax.naming.InitialContext();
}catch (Exception ex){
nbUtility.logError(ex,"Error while creating Initial Context
try{
// DEBUG:
System.out.println("ejbCreate(): NB_DATASOURCE = " +
props.getPropertyValue(props.NB_DATASOURCE));
// DEBUG:
dataSourceObj = (javax.sql.DataSource)
ctx.lookup(_props.getPropertyValue(_props.NB_DATASOURCE));
catch (Exception ex){
ex.printStackTrace();
if (dataSourceObj == null)
throw new javax.ejb.CreateException("Couldn't get DataSource
object from environment");
} else {
throw new javax.ejb.CreateException("Couldn't create the
property manager: NB_CONFIG_FILE is null, empty, not set, or thefile
doesn't exist.");
* Given a customer number, this method
* returns the list of accounts that belongs to
* this customers.
public nbAccountList getAccountList(String CustomerNo)
throws java.rmi.RemoteException {
nbAccountList accountList = null;
if ((CustomerNo != null) && (!CustomerNo.equals(""))) {
java.sql.Connection conn = null;
java.sql.Statement stmt = null;
java.sql.ResultSet rset = null;
try {
accountList = new nbAccountList();
String sql = "SELECT * FROM " +
props.getPropertyValue(props.NB_DBTABLE_ACCOUNT)
+
" WHERE " +
"(" +
props.getPropertyValue(props.NB_DBFIELD_ACCOUNT_CUSTOMERNO) +
"='" + CustomerNo + "')";
// DEBUG:
nbDebug.write("accounts list SQL= " + sql);
// DEBUG:
// Let's get the connection, the statement, and the record
set.
conn = dataSourceObj.getConnection();
stmt = conn.createStatement();
rset = stmt.executeQuery(sql);
// Let's loop for each single account
int index = 0;
nbAccount account = null;
while (rset.next()) {
String AccountNo =
rset.getString(_props.getPropertyValue(_props.NB_DBFIELD_ACCTPERMIS_ACCOUNTN
O));
>
// Instantiate an account object
account = new nbAccount(AccountNo);
index++;
} catch (SQLException e) {
nbUtility.logError(e, "SQLException while trying to get
accounts data.");
} finally {
try {
if (rset != null) { rset.close(); rset = null; }
if (stmt != null) { stmt.close(); stmt = null; }
if (conn != null) { conn.close(); conn = null; }
} catch (SQLException e) {
nbUtility.logError(e, "SQLException while trying to close
connection.");
return (accountList);
Try our New Web Based Forum at http://softwareforum.sun.com
Includes Access to our Product Knowledge Base!