PL/Java, 1.0.0 beta 4

With this release, the Pl/Java project has reached its fourth major milestone

A source tarball and a variety of binaries can be found in the download area. Two for Windows. one win32 native for PostgreSQL 8.0 and one cygwin based for older PostgreSQL versions. On Linux PL/Java also comes in a GNU Java (GCJ) flavor where the actual pljava.jar is compiled into the pljava shared object.

Prerequisites

Get the binary distribution of Pl/Java for your platform. Unzip it into a directory of your own choice.

Postmaster configuration

Get the PostgreSQL environment up and running. You will need to modify the postgresql.conf file.

 

With PostgreSQL 7.4.x you must make the postmaster accept TCP/IP connections (needed by the client JDBC driver). So ensure that you have:

tcpip_socket = true

In order to find the PL/Java shared object, you can do one of two things. Either you install the shared object in a directory already searched by the postmaster (such as the data directory) or you tell the postmaster where to find it using the dynamic_library_path. I.e. you have a setting similar to this:

dynamic_library_path = '$libdir:<pljava installation>/pljava.jar'

Note that on the win32 platform (not cygwin) you need to use a semicolon as a path separator and double backslashes (since backslash is the escape character in the postgresql.conf file) as directory separators.

In order to see the logging from the tests add the following:

log_min_messages = info

PostgreSQL 8.0 adds the ability do define custom variable classes to the postgresql.conf file. Add the following entrires:

custom_variable_classes = 'pljava'
pljava.classpath = <pljava installation>/pljava.jar

The pljava.classpath is not needed when you run GCJ since the pljava.jar is compiled into the shared object.
 

Using PostgreSQL 7.4, the postgresql.conf have no entry to configure Java specific environment variables yet so you will need use an external environment setting:

export CLASSPATH=<pljava installation>/pljava.jar.

Finally, unless you use GCJ, the postmaster must be made aware of the location of the Java runtime shared objects. This accomplished by setting the LD_LIBRARY_PATH (Unix) or PATH (Windows). A standard install on an Intel Linux box will need:

export LD_LIBRARY_PATH=$JAVA_HOME/jre/lib/i386:$JAVA_HOME/jre/lib/i386/client.

Note: Some discussions took place on the postgres hackers list wether or not the LD_LIBRARY_PATH could be set using the dynamic_library_path but it was concluded that it would be too difficult. In essence, the postmaster would need to restart itself in order for the setting to become effective since the loader is initialized when the process is created.

You are now ready to start the postmaster.

Deploying the Pl/Java

Pl/Java adds a schema named SQLJ to the database (the naming is from the proposed SQL standard for Java backend mapping) and adds a couple of tables and functions to that schema. A deploy program exists that should be used for this purpose. In order to run this program, you must see to that the PostgreSQL jdbc driver package postgresql.jar and the deploy.jar file is in your CLASSPATH, then run:

java org.postgresql.pljava.deploy.Deployer
This will result in a list of options. Typically you would use something like:
java org.postgresql.pljava.deploy.Deployer -install -user <your name>

That's all there's to it. You are now ready to start using the Pl/Java system. If the server runs on a Cygwin system you will need to add the option -windows. The reason for this is that PostgreSQL and Java dynamic loading uses different naming on Windows.

Run the example tests

The tests are divided into two jar files. One is the client part found in the test.jar. It contains some methods that executes SQL statements and prints the output (all contained there can of course also be executed from psql or any other client). The other is the example.jar which contains the sample code that runs in the backend. The latter must be installed in the database in order to function. An easy way to do this is to use psql and issue the command:

SELECT sqlj.install_jar('file:///some/directory/example.jar', 'samples',  true);

If this command succeeds, everything is working correctly. You may get a couple of errors here though.

Once loaded, you must also set the classpath used by the Pl/Java runtime. This classpath is set per schema (namespace). A schema that lacks a classpath will default to the classpath that has been set for the public schema. The tests will use the schema javatest. To define the classpath for this schema, simply use psql and issue the command:

SELECT sqlj.set_classpath('javatest', 'samples');

The first argument is the name of the schema, the second is a colon separated list of jar names. The names must reflect jars that are installed in the system.

Now, you should be able to run the tests:

java org.postgresql.pljava.test.Tester