PLJava, 1.1.x

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) and two for i386 based Linux. Although all pre-compiled binaries must run using a standard JVM, the PLJava can also be compiled and linked using GNU GCJ. PLJava has no pre-compiled binaries for GCJ since the needed 4.0 version has not yet been released but the make system contain what's needed to make the build easy.

Please note that all use of GCJ should be regarded as experimental. The lack of a proper 4.0.0 release is not the only problem. Due to limitations in the GCJ implementation of java.security, the PLJava trusted language implementation is not really trusted when using GCJ.

Prerequisites

Get the binary distribution of PLJava 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 PLJava 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>'

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 entry:

custom_variable_classes = 'pljava'

System classpath

Normally, all Java code is loaded into the database using the install_jar/replace_jar SQL functions. Most of PLJava (those functions included) is however implemented in Java. Unless you use GCJ, where this Java code is compiled and linked with the pljava shared object module, this hen and egg problem needs to be resolved using the system classpath. If you have PostgreSQL 8.0 or later, you add the following entry to the postgresql.conf file:

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

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

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

Shared object issues

Unless you use GCJ, the postmaster must be made aware of the location of the shared objects used by the Java Runtime Environment (JRE). 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.

Apparently, on some Linux platforms you will also need to include $JAVA_HOME/jre/lib/i386/native_threads.

zlib conflict

On some platforms there will be a conflict between the libzip.so included in the JRE and the libz.so used by PostgreSQL (the JRE libzip.so includes a libz.so). The symptom is an InternalError in the java.util.zip.Inflater.init when an attempt is made to load the first class. You can verify the version of libzip.so using the following command:

strings libzip.so | fgrep Copyright

The problem can be resolved in one of the following ways depending on your needs and ability to recompile:

You are now ready to start the postmaster.

Deploying the PLJava

PLJava 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. The deployment can be done in one of two ways. The simplest way is probably to just execute the file install.sql as a super user (the uninstall.sql will remove the pljava installation). PLJava also comes with deploy program that lets you install, reinstall, or uninstall PLJava. This program will assert that you indeed are a super user and then execute the correct commands using jdbc. 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

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

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 examples.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/examples.jar', 'samples',  true);

Please note that the deployment descriptor stored in examples.jar will attempt to create the schema javatest so the user that executes the sqlj.install_jar must have permission to do that. 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 PLJava 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.

NOTE: If you don't use schemas, you must still issue the set_classpath command to assign a correct classpath to the 'public' schema. This can only be done by a super user.

 

Now, you should be able to run the tests:

java org.postgresql.pljava.test.Tester

Building

Building should be very stright forward: