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| e-docs > WebLogic Server > Programming WebLogic JDBC > Testing JDBC Connections and Troubleshooting |
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Programming WebLogic JDBC
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Testing JDBC Connections and Troubleshooting
The following sections describe how to test, monitor, and troubleshoot JDBC connections:
The Administration Console provides tables and statistics to enable monitoring the connectivity parameters for each of the subcomponents—Connection Pools, MultiPools and DataSources.
You can also access statistics for connection pools programmatically through the JDBCConnectionPoolRuntimeMBean; see WebLogic Server Partner's Guide and the WebLogic Javadoc. This MBean is the same API that populates the statistics in the Administration Console. Read more about monitoring connectivity in JDBC Connection Pools .
For information about using MBeans, see Programming WebLogic JMX Services.
Validating a DBMS Connection from the Command Line
Use BEA utilities to test two-tier and three-tier JDBC database connections after you install WebLogic Server.
Testing a Two-Tier Connection from the Command Line
To use the utils.dbping utility, you must complete the installation of your JDBC driver. Make sure you have completed the following:
Use the utils.dbping utility to confirm that you can make a connection between Java and your database. The dbping utility is only for testing a two-tier connection, using a WebLogic two-tier JDBC driver like WebLogic jDriver for Oracle.
$ java utils.dbping DBMS user password DB
Valid username for database login. Use the same values and format that you use with isql for SQL Server or sqlplus for Oracle.
Valid password for the user. Use the same values and format that you use with isql or sqlplus.
Name of the database. The format varies depending on the database and version. Use the same values and format that you use with isql or sqlplus. Type 4 drivers, such as MSSQLServer4, need additional information to locate the server since they cannot access the environment.
Connect to Oracle from Java with WebLogic jDriver for Oracle using the same values that you use with sqlplus.
If you are not using SQLNet (and you have ORACLE_HOME and ORACLE_SID defined), follow this example:
$ java utils.dbping ORACLE scott tiger
If you are using SQLNet V2, follow this example:
$ java utils.dbping ORACLE scott tiger TNS_alias
where TNS_alias is an alias defined in your local tnsnames.ora file.
Microsoft SQL Server (Type 4 driver)
To connect to Microsoft SQL Server from Java with WebLogic jDriver for Microsoft SQL Server, you use the same values for user and password that you use with isql. To specify the SQL Server, however, you supply the name of the computer running the SQL Server and the TCP/IP port the SQL Server is listening on. To log into a SQL Server running on a computer named mars listening on port 1433, enter:
$ java utils.dbping MSSQLSERVER4 sa secret mars:1433
You could omit ":1433" in this example since 1433 is the default port number for Microsoft SQL Server. By default, a Microsoft SQL Server may not be listening for TCP/IP connections. Your DBA can configure it to do so.
Validating a Multitier WebLogic JDBC Connection from the Command Line
Use the utils.t3dbping utility to confirm that you can make a multitier database connection using a WebLogic Server. The t3dbping utility is only for testing a multitier connection, after you have verified that you have a working two-tier connection, and after you have started WebLogic.
If the two-tier JDBC driver is a WebLogic jDriver, you should test the two-tier connection with utils.dbping. Otherwise, see the documentation for the two-tier JDBC driver to find out how to test that connection before you test the multitier connection.
$ java utils.t3dbping URL user password DB driver_class driver_URL
Name of the database. Use the same values and format that are shown above for testing a two-tier connection.
Class name of the JDBC driver between WebLogic and the DBMS. For instance, if you are using WebLogic jDriver for Oracle on the server side, the driver class name is weblogic.jdbc.oci.Driver. Note that the class name of the driver is in dot-notation format.
URL of the JDBC driver between WebLogic and the DBMS. For instance, if you are using WebLogic jDriver for Oracle on the server side, the URL of the driver is jdbc:weblogic:oracle. Note that the URL of the driver is colon-separated.
These examples are displayed on multiple lines for readability. Each example should be entered as a single command.
Here is an example of how to ping the Oracle DBMS DEMO20 running on the server bigbox, on the same host as WebLogic, which is listening on port 7001:
$ java utils.t3dbping // command
t3://bigbox:7001 // WebLogic URL
scott tiger // user password
DEMO20 // DB
weblogic.jdbc.oci.Driver // driver class
jdbc:weblogic:oracle // driver URL
DB2 with AS/400 Type 4 JDBC driver
This example shows how to ping an AS/400 DB2 database from a workstation command shell using the IBM AS/400 Type 4 JDBC driver:
$ java utils.t3dbping // command
t3://as400box:7001 // WebLogic URL
scott tiger // user password
DEMO // database
com.ibm.as400.access.AS400JDBCDriver // driver class
jdbc:as400://as400box // driver URL
WebLogic jDriver for Microsoft SQL Server (Type 4 JDBC driver)
This example shows how to ping a Microsoft SQL Server database using WebLogic jDriver for Microsoft SQL Server:
$ java utils.t3dbping // command
t3://localhost:7001 // WebLogic URL
sa // user name
abcd // password
hostname // database@hostname:port
//(optional if specified
// as part of the URL)
weblogic.jdbc.mssqlserver4.Driver // driver class
jdbc:weblogic:mssqlserver4:pubs@localhost:1433
// driver URL:database@hostname:port
//(optional if used in the database parameter)
The following sections provide troubleshooting tips.
If you are testing a connection to WebLogic, check the WebLogic Server log. By default, the log is kept in a file with the following format:
domain\server\server.log
Where domain is the root folder of the domain and server is the name of the server. The server name is used as a folder name and in the log file name.
If you get an error message that indicates that the .dll failed to load, make sure your PATH includes the 32-bit database-related .dlls.
If you get an error message that indicates that an .so or an .sl failed to load, make sure your LD_LIBRARY_PATH or SHLIB_PATH includes the 32-bit database-related files.
WebLogic supports Oracle codesets with the following consideration:
For more information, see Codeset Support in Using WebLogic jDriver for Oracle.
Other Problems with Oracle on UNIX
Check the threading model you are using. Green threads can conflict with the kernel threads used by OCI. When using Oracle drivers, WebLogic recommends that you use native threads. You can specify this by adding the -native flag when you start Java.
Thread-related Problems on UNIX
On UNIX, two threading models are available: green threads and native threads. For more information, read about the JDK for the Solaris operating environment on the Sun Web site.
You can determine what type of threads you are using by checking the environment variable called THREADS_TYPE. If this variable is not set, you can check the shell script in your Java installation bin directory.
Some of the problems are related to the implementation of threads in the JVM for each operating system. Not all JVMs handle operating-system specific threading issues equally well. Here are some hints to avoid thread-related problems:
$ echo $SHLIB_PATH
BEA Systems recommends—and good programming practice dictates—that you always close JDBC objects, such as Connections, Statements, and ResultSets, in a finally block to make sure that your program executes efficiently. Here is a general example:
try {Driver d =
(Driver)Class.forName("weblogic.jdbc.oci.Driver").newInstance();
Connection conn = d.connect("jdbc:weblogic:oracle:myserver",
"scott", "tiger");Statement stmt = conn.createStatement();
stmt.execute("select * from emp");
ResultSet rs = stmt.getResultSet();
// do work
}
catch (Exception e) {// deal with any exceptions appropriate
}
finally { try {rs.close();}
catch (Exception rse) {}
try {stmt.close();}
catch (Exception sse) {}
try {conn.close();
catch (Exception cse) {}}
Troubleshooting Problems with Shared Libraries on UNIX
When you install a native two-tier JDBC driver, configure WebLogic Server to use performance packs, or set up BEA WebLogic Server as a Web server on UNIX, you install shared libraries or shared objects (distributed with the WebLogic Server software) on your system. This document describes problems you may encounter and suggests solutions for them.
The operating system loader looks for the libraries in different locations. How the loader works differs across the different flavors of UNIX. The following sections describe Solaris and HP-UX.
Use the procedures for setting your shared libraries as described in this document. The actual path you specify will depend on your Oracle client version, your Oracle Server version and other factors. For details, see Installing WebLogic jDriver for Oracle.
To find out which dynamic libraries are being used by an executable you can run the ldd command for the application. If the output of this command indicates that libraries are not found, then add the location of the libraries to the LD_LIBRARY_PATH environment variable as follows (for C or Bash shells):
# setenv LD_LIBRARY_PATH weblogic_directory/lib/solaris/oci817_8
Once you do this, ld should no longer complain about missing libraries.
Incorrectly Set File Permissions
The shared library problem you are most likely to encounter after installing WebLogic Server on an HP-UX system is incorrectly set file permissions. After installing WebLogic Server, make sure that the shared library permissions are set correctly with the chmod command. Here is an example to set the correct permissions for HP-UX 11.0:
% cd WL_HOME/lib/hpux11/oci817_8
% chmod 755 *.sl
If you encounter problems loading shared libraries after you set the file permissions, there could be a problem locating the libraries. First, make sure that the WL_HOME/server/lib/hpux11 is in the SHLIB_PATH environment variable:
% echo $SHLIB_PATH
If the directory is not listed, add it:
# setenv SHLIB_PATH WL_HOME/server/lib/hpux11:$SHLIB_PATH
Alternatively, copy (or link) the .sl files from the WebLogic Server distribution to a directory that is already in the SHLIB_PATH variable.
If you still have problems, use the chatr command to specify that the application should search directories in the SHLIB_PATH environment variable. The +s enabled option sets an application to search the SHLIB_PATH variable. Here is an example of this command, run on the WebLogic jDriver for Oracle shared library for HP-UX 11.0:
# cd weblogic_directory/lib/hpux11
# chatr +s enable libweblogicoci38.sl
Check the chatr man page for more information on this command.
You may also encounter a shared library problem if you do not include the proper paths in your SHLIB_PATH when using Oracle 9. SHLIB_PATH should include the path to the driver (oci901_8) and the path to the vendor-supplied libraries (lib32). For example, your path may look like:
export SHLIB_PATH=
$WL_HOME/server/lib/hpux11/oci901_8:$ORACLE_HOME/lib32:$SHLIB_PATH
Note also that your path cannot include the path to the Oracle 8.1.7 libraries, or clashes will occur. For more instructions, see Setting Up the Environment for Using WebLogic jDriver for Oracle.
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