通过连接防止 Oracle 数据库错误

Question

I have some trouble but not necessary.

Because my JSP/Servlet is work fine but sometime I have these connection Error Like this

Connection Error Records:

 ORA-02396: exceeded maximum idle time, please connect again ORA-01012: not logged on ORA-00604: error occurred at recursive SQL level 1 ORA-02399: exceed maximum connect time, you are being logged off

.jsp

<%@ page import="java.sql.ResultSet" %>
<%@ page import="java.sql.SQLException" %>
<%@ page import="java.sql.Statement" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.DriverManager" %>
<%@ page import="my.OracleConnectionPool" %>
<%@ page pageEncoding="UTF-8"%>
<% 
Connection connect = null;
Statement s = null;
try {        
   Class.forName("oracle.jdbc.driver.OracleDriver");
   connect =  OracleConnectionPool.getConnection();
   s = connect.createStatement();
   String sql = "SELECT * FROM table";
   ResultSet rec = s.executeQuery(sql);
   //Do something
} catch (Exception e) {
   out.println(e.getMessage());
   e.printStackTrace();
} finally {
   try {
      s.close();
      connect.close();
   } catch (SQLException ex) {
      out.println(e.getMessage());
      e.printStackTrace();
   }
}
%>

my.OracleConnectionPool this will get connection from wildfly

package my;

import javax.naming.NamingException;
import java.sql.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
public class OracleConnectionPool {
  public OracleConnectionPool() {
  }
  public static Connection getConnection()
          throws SQLException {
    try {
      Context ctx = new InitialContext();
      DataSource ods = null;
      ods = (DataSource)ctx.lookup("java:/MYCON");
      if (ods == null) {
        throw new SQLException("OracleDataSource is null.");
      }
      return ods.getConnection();
    } catch (NamingException ex) {
      return null;
    }
  }
}

For the Standalone.xml

<datasource enabled="true" pool-name="MYCON" jndi-name="java:/MYCON" use-ccm="false" jta="true">
   <connection-url>jdbc:oracle:thin:@myhost:1521:ODS</connection-url>
   <driver-class>oracle.jdbc.OracleDriver</driver-class>
   <driver>ojdbc6.jar</driver>
   <security>
      <user-name>myuser</user-name>
      <password>********</password>
   </security>
   <validation>
      <valid-connection-checker class-name="org.jboss.jca.adapters.jdbc.extensions.oracle.OracleValidConnectionChecker"/>
      <background-validation>true</background-validation>
      <stale-connection-checker class-name="org.jboss.jca.adapters.jdbc.extensions.oracle.OracleStaleConnectionChecker"/>
      <exception-sorter class-name="org.jboss.jca.adapters.jdbc.extensions.oracle.OracleExceptionSorter"/>
   </validation>
</datasource>

How can I prevent or skip these error? Should I try the refresh servlet/connect test first?

Update: Because I can't change Oracle's PDA

Answer 1

There might be a problem with your database profiles. Even if you can workaround the problem with connection pool settings, you should still try to fix this on the database side. If you see this problem once, chances are it's impacting other users and other tools that may not have a workaround.

First, find out which profile applies to your user:

select username, profile
from dba_users
order by username;

The most common way for these problems to occurs is for users to be in the wrong profile. Make sure your application account is not stuck in a user profile. DBAs typically set up at least two kinds of profiles - one for user accounts, that forces disconnects, and one for application accounts, that never forces disconnects.

If the user is in the right profile, check the profile values. Your application user should probably have a value of UNLIMITED for the resources CONNECT_TIME and IDLE_TIME .

select profile, resource_name, limit
from dba_profiles
where resource_name in ('IDLE_TIME', 'CONNECT_TIME')
order by 1,2;

If your application profile is set to a small value, you may need to run a command like this:

alter profile your_profile limit connect_time unlimited;