Getting Stale Connection using OracleDataSource with OCI driver

Question

I am getting stale connection error when there is no requests to the database from my java application for couple of hours.

Its a simple java application runned on Linux box with OCI (type driver). Dont ask me why OCI, why not thin. I am using OracleDataSource and OracleConnectionCacheManager for maintaining the cache of connection objects. Here is the code snippet:

import java.sql.Connection; 
import java.sql.SQLException; 
import java.util.Properties; 

import oracle.jdbc.pool.OracleConnectionCacheManager; 
import oracle.jdbc.pool.OracleDataSource; 

import org.apache.log4j.Logger; 

import com.exception.DataException; 

public class ConnectionManager { 
private static OracleDataSource poolDataSource = null; 
private final static String CACHE_NAME = "CONNECTION_POOL_CACHE"; 
private static OracleConnectionCacheManager occm = null; 

public static void init(String url,String userId,String password) throws PCTDataException{ 
Properties cacheProps = null; 
try { 
poolDataSource = new OracleDataSource(); 
poolDataSource.setURL(url); 
poolDataSource.setUser(userId); 
poolDataSource.setPassword(password); 

cacheProps = new Properties(); 
cacheProps.setProperty("MinLimit", "1"); 
cacheProps.setProperty("MaxLimit", "5"); 
cacheProps.setProperty("InitialLimit", "1"); 
cacheProps.setProperty("ValidateConnection", "true"); 

poolDataSource.setConnectionCachingEnabled(true); 
occm = OracleConnectionCacheManager.getConnectionCacheManagerInstance(); 
occm.createCache(CACHE_NAME, poolDataSource, cacheProps); 
occm.enableCache(CACHE_NAME); 
} catch (SQLException se) { 
throw new DataException("SQL Exception while initializing connection pool"); 
}catch(Exception e){ 
throw new DataException("Exception while initializing connection pool"); 
} 
} 

public static Connection getConnection() throws PCTDataException { 
try{ 
if (poolDataSource == null) { 
throw new SQLException("OracleDataSource is null."); 
} 
occm.refreshCache(CACHE_NAME, OracleConnectionCacheManager.REFRESH_INVALID_CONNECTIONS); 
Connection connection = poolDataSource.getConnection(); 
return connection; 
}catch(SQLException se){ 
se.printStackTrace(); 
throw new DataException("Exception while getting Connection object"); 
}catch(Exception e){ 
e.printStackTrace(); 
throw new DataException("Exception while getting Connection object"); 
} 
} 

public static void closePooledConnections() { 
try{ 
if (poolDataSource != null) { 
poolDataSource.close(); 
} 
}catch(SQLException se){ 
}catch(Exception e){ 
} 

} 
} 

The error is as follows:

ConnectionManager.java:getConnection:87 - Exception while getting Connection object: 
java.sql.SQLException: Invalid or Stale Connection found in the Connection Cache 
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112) 
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146) 
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:208) 
at oracle.jdbc.pool.OracleImplicitConnectionCache.getConnection(OracleImplicitConnectionCache.java:390) 
at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java:404) 
at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java:189) 

What am I missing?

Answer 1

Maybe you need to set keep alives on? what this does is periodically, when not in use it send a ping to the database server basically saying I am still here and don't close me out. This is not that fun to try to debug though. The problem could be a setting on your database server where there is a max connection age, or a time to kill idle connections. There also could be some settings in your pool that you could use to that would check for this and then just tell it to get a new one when this happens. I wish I could be more help but I have not worked with oracle.