Common Jdbc Issues-1).
If you get the following Error:
01 | <BEA-149205> <Failed to initialize the application ‘TestDataSource’ due to error weblogic.application.ModuleException: . |
02 | weblogic.application.ModuleException: |
03 | at weblogic.jdbc.module.JDBCModule.prepare(JDBCModule.java:289) |
04 | at weblogic.application.internal.flow.ModuleListenerInvoker.prepare(ModuleListenerInvoker.java:93) |
05 | at weblogic.application.internal.flow.DeploymentCallbackFlow$1.next(DeploymentCallbackFlow.java:387) |
08 | weblogic.common.ResourceException: Could not create pool connection. The DBMS driver exception was: The Network Adapter could not establish the connection |
09 | - – - – - – or - – - – - - |
10 | weblogic.common.ResourceException: weblogic.common.ResourceException: Could not create pool connection. The DBMS driver exception was: Io exception: The Network Adapter |
Degugging the root Cause of above Issue:
The Above
Exception: java.io.IOException: The Network Adapter could not establish the
connection
It simply suggest that the Database URL may not be correct in the DataSource
XML file locatied inside “<DOMAIN_HOME>\config\jdbc” directoryor may be
the TNS name OR some n/w issue between WLS BOX and the DB Box. Please try the
following to Double Check it.
Step1). Add JDBC Driver
also in the Classpath or Better run
“. ./setWLSEnv.sh”
(
NOTE: While running the above script please use two DOTs
like mentioned above. The first DOT represents that set the Environment in the
Current Shell and the second DOT (./) Slash represents that pick up the Script
from the current Location. Both DOTs are separated by a single space. Once u run
“. ./setWLSEnv.sh” after that try to echo the values of $CLASSPATH and $PATH to
make sure that the env is set properly)
Step2). Use WLS
dbping utility to test the Database Network Connectivity from
the WebLogic Server Box:
Syntax:
java -classpath
/bea103/wl_server103/server/lib/weblogic.jar utils.dbping ORACLE_THIN
<dbUserName> <dbPasswoes> <dbURL>
java -classpath $WLSHOME/server/lib/weblogic.jar utils.dbping ORACLE_THIN SOA_SOAINFRA password 10.15.35.0:1525/SID14
Example:
java -classpath
/bea103/wl_server103/server/lib/weblogic.jar utils.dbping ORACLE_THIN scott
tiger databaseHostName:1521:P15215h
Step 3). Try doing a
telnet to connect to the Database Box on the Database Listen
Port like following Just to make sure that the Database has started listening on
the Mentioned Listen Port or Not …..:
telnet databaseHostName
1521
————————————————————————–
Common Jdbc Issues-2).
Many times we see that DataSource configured on WebLogic Server was running
fine sometimes back and suddenly we start seeing the following Error:
1 | Caused by: java.sql.SQLException: Io exception: Got minus one from a read call |
2 | at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112) |
3 | at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146) |
4 | at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:255) |
5 | at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387) |
6 | at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:420) |
Degugging the root Cause of above Issue:
The error
“
Caused by: java.sql.SQLException: Io exception: Got minus one from a read
call” clearly indicates the root cause of this issue. “We get the following
error “Got minus one from a read call” if the
Database goes under
Maintenance…..or Database is in inconsistent State (Due to any reason
like Database Maintenance or Database unmounting…etc ).
WLS is asking a JDBC driver for a connection and getting that exception,
which means the DBMS or network dropped the socket during the driver-DBMS
handshake.
The above error ensures that there is Nothing Wrong from WebLogic Side …we
need to contact the Database Administrator only.
Step1). Open the Server
Log and check the timestamp of the first occurance of that Error in the Server
log.
Step2). Confirm with the
Database Administrator…. What was the activity happening on the Database side at
that time (90% cases u will find that the Database might be under Maintenance
that time)
——-Make Use of Appropriate Debug
Flags:———
-Dweblogic.resourcepool.max_test_wait_secs=xx
Where xx is
the amount of time, in seconds, WebLogic Server waits for connection test before
considering the connection test failed. By default, a server instance is
assigned a value of 10 seconds. This command line flag manages failures, such as
a DBMS network failure, which can cause connection tests and applications to
hang for extended periods of time (for example, 10 minutes). If the assigned
time period expires, the server instance purges and disables the pool (closes
all connections and blocks further reserve attempts) and re-enables the pool as
soon as it is possible to reconnect.
You can use the following Debug
Flags:
-Dweblogic.debug.DebugJDBCSQL=true
-Dweblogic.log.StdoutSeverity=Debug
Use the Following WLST Script to Enable the JDBC related Debug
Flags
“ExampleDebugJdbc.py”
—————————————————————–
user=’weblogic’
password=’weblogic’
url=’t3://localhost:7001′
connect(user,
password,
url)
edit()
cd(‘Servers/TestServer/ServerDebug/TestServer’)
startEdit()
set(‘DebugJDBCSQL’,'true’)
save()
activate()
—————————————————————–
Common Jdbc Issues-3).
If you see that the Database is going into
DataSource is moving to SUSPENDED/Disabled State….The first of
all check the database connectivity. If the dfatabase connectivity is OK and WLS
is able to establish the Connectivity with the database Successfully then Please
try to use the “weblogic.Admin” utility to Restore (Resume) the DataSource.
You can use “weblogic.Admin” utility to Enable and Disable the Pool
(DataSource) Just to Confirm whether the dataSource is actually active or
not:
Step1). run
“.
./setWLSEnv.sh” first in the same Shell prompt….then do the
following:
Step2). To
suspend:
java weblogic.Admin -url t3://localhost:7001 -username
weblogic -password weblogic SUSPEND_POOL YourDataSourceName
Step3). To
re-enable:
java weblogic.Admin -url t3://localhost:7001 -username
weblogic -password weblogic RESUME_POOL YourDataSourceName
To test whether you are getting any Exception or Error while doing this….If
yes u are getting any Error or exception then It means there May be some
Database connectivity issue…
If a datasource gets destroyed then even if u
are having DataSource Configuration Entries in the “config.xml” and
the
“<DOMAIN_HOME>/config/jdbc/*.xml” files
…still u wont be able to see that datasource in the Monitoring Tab in the
AdminConsole. Because as soon as the datasource gets destroyed (Due to N/W
disconnect or someother reason) the MBean Object gets destroyed.
Common Jdbc Issues-4).
1 | <Warning> <JDBC> <BEA-001153> <Forcibly releasing inactive connection |
2 | “weblogic.jdbc.wrapper.PoolConnection_oracle_jdbc_driver_T4CConnection@3″ back into the connection pool “TestDataSource”, currently reserved by: java.lang.Exception |
3 | at weblogic.jdbc.common.internal.ConnectionEnv.setup(ConnectionEnv.java:291) |
4 | at weblogic.common.resourcepool.ResourcePoolImpl.reserveResource(ResourcePoolImpl.java:314) |
5 | at weblogic.common.resourcepool.ResourcePoolImpl.reserveResource(ResourcePoolImpl.java:292) |
6 | at weblogic.jdbc.common.internal.ConnectionPool.reserve(ConnectionPool.java:425) |
7 | at weblogic.jdbc.common.internal.ConnectionPool.reserve(ConnectionPool.java:316) |
If we see above kind of exceptions in our Server Logs then definately we need
to look into the Application Code.
“That is either your application
reserving and Hholding the jdbc connections (they aren’t lost means leaked), or
maybe they are hanging waiting for the DBMS to respond.”
Usually we see this Warning When the Application code obtains a JDBC
connection from the WLS datasource, then not using it and not closing it, Means
Just Holding the Connection Reference, for longer than your datasource/pool is
configured to allow (IdleConnectionTimeout). Make sure that u close all the JDBC
related Objects in a proper sequence. like exactly in the following
Order…Always close the ResultSet, Statement and Connection objects insode the
finally{} Block in the following order:
2 | try {resultset.close();} |
3 | catch (Exception rse) {} |
4 | try {statement.close();} |
5 | catch (Exception sse) {} |
6 | try {connection.close(); |
7 | catch (Exception cse) {} |
Common Jdbc Issues-5).
Many times we get the following kind of error/exception while using a
Connection object:
01 | java.sql.SQLException: Closed Connection |
02 | at oracle.jdbc.driver.SQLStateMapping.newSQLException(SQLStateMapping.java:70) |
03 | at oracle.jdbc.driver.DatabaseError.newSQLException(DatabaseError.java:133) |
04 | at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:199) |
05 | at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:263) |
06 | at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:271) |
07 | at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:445) |
08 | at oracle.jdbc.driver.OracleStatement.ensureOpen(OracleStatement.java:3620) |
09 | at oracle.jdbc.driver.OracleCallableStatement.execute(OracleCallableStatement.java:3853) |
10 | at oracle.jdbc.driver.OraclePreparedStatementWrapper.execute(OraclePreparedStatementWrapper.java:1374) |
11 | at weblogic.jdbc.wrapper.PreparedStatement.execute(PreparedStatement.java:99) |
In these cases we need to make sure that you enable the “Test Connection On
Reserve” is disabled. for your Connection Pool.This is the best way the pool can
ensure That connection pool provides us a good connection when an application
ask for it.
Also provide a simple SQL query for connection testing in the
DataSource configuration like ‘SELECT * FROM DUAL’
Common Jdbc Issues-6).
If you get the following Error:
01 | java.sql.SQLException: No more data to read from socket |
02 | at oracle.jdbc.driver.T4CMAREngine.unmarshalUB1(T4CMAREngine.java:1200) |
03 | at oracle.jdbc.driver.T4CMAREngine.unmarshalSB1(T4CMAREngine.java:1155) |
04 | at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:279) |
05 | at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:186) |
06 | at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:521) |
07 | at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:194) |
08 | at oracle.jdbc.driver.T4CStatement.executeForDescribe(T4CStatement.java:853) |
09 | at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1145) |
10 | at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1267) |
11 | at oracle.jdbc.driver.OracleStatement.executeInternal(OracleStatement.java:1882) |
12 | at oracle.jdbc.driver.OracleStatement.execute(OracleStatement.java:1847) |
13 | at oracle.jdbc.driver.OracleStatementWrapper.execute(OracleStatementWrapper.java:301) |
This error occurs if an applications that uses a database connections from
the DataSource/Pool and When the application checked out a connection that has
been already “timed out” or has been “staled”, still the application uses it to
connect to the database, this error occurs.
In this case eother we need to start the Oracle Database Server or the
Application Server which is maintaining the Connection Pool (Reseting the
DataSource is also a valid option) sothat the staled connection should be
cleared out and a new connection should be establised automatically.
