4.10.2 Compiling and Running a Custom PGX Algorithm

To be able to compile and run a custom PGX algorithm, you must perform the following actions:

1. Set the following two configuration parameters in the conf/pgx.conf file:
   • Set the graph_algorithm_language option to JAVA.
   • Set the java_home_dir option to the path to your Java home (use <system-java-home-dir> to have PGX infer Java home from the system properties).

   {
     "graph_algorithm_language": "JAVA",
     "java_home_dir": "<system-java-home-dir>"
   }

2. Create a session.
   • JShell
   • Java
   • Python

   cd /opt/oracle/graph
   ./bin/opg4j 

   import oracle.pgx.algorithm.*;
   PgxSession session = Pgx.createSession("my-session");

   session = instance.create_session("my-session")

3. Compile a PGX Algorithm. For example:
   • JShell
   • Java
   • Python

   opg4j> var myAlgorithm = session.compileProgram("/path/to/MyAlgorithm.java")
   myAlgorithm ==> CompiledProgram[name=MyAlgorithm]

   import oracle.pgx.algorithm.CompiledProgram;
   CompiledProgram myAlgorithm = session.compileProgram("/path/to/MyAlgorithm.java");

   my_algorithm = session.compile_program("/path/to/MyAlgorithm.java")

4. Run the algorithm. For example:
   • JShell
   • Java
   • Python

   opg4j> var graph =session.readGraphWithProperties("/path/to/bank_graph_analytics.json")
   graph ==> PgxGraph[name=bank_graph_analytics,N=1000,E=5001,created=1633504705054]
   opg4j> var property = graph.createVertexProperty(PropertyType.INTEGER)
   property ==> VertexProperty[name=vertex_prop_integer_9,type=integer,graph=bank_graph_analytics]
   opg4j> myAlgorithm.run(graph, property)
   $6 ==> {
     "success" : true,
     "canceled" : false,
     "exception" : null,
     "returnValue" : 42,
     "executionTimeMs" : 0
   }

   import oracle.pgx.algorithm.VertexProperty;
   PgxGraph graph = session.readGraphWithProperties("/path/to/bank_graph_analytics.json");
   VertexProperty property = graph.createVertexProperty(PropertyType.INTEGER);
   myAlgorithm.run(graph, property);

   graph = session.read_graph_with_properties("/path/to/bank_graph_analytics.json")
   property = graph.create_vertex_property("integer")
   my_algorithm.run(graph, property)
   {'success': True, 'canceled': False, 'exception': None, 'return_value': 42, 'execution_time(ms)': 1}