16.6.2 Compiling and Running a Custom PGX Algorithm

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

Note:

Compiling a custom PGX Algorithm using the PGX Algorithm API is not supported on Oracle JDK 17. See System Requirements for Installing Oracle Graph Server to use an alternative JDK version supported by the graph server (PGX).

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.readGraphByName("BANK_GRAPH_VIEW",GraphSource.PG_VIEW)
   g ==> PgxGraph[name=BANK_GRAPH_VIEW_2,N=999,E=4993,created=1689325558251]
   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.readGraphByName("BANK_GRAPH_VIEW",GraphSource.PG_VIEW);
   VertexProperty property = graph.createVertexProperty(PropertyType.INTEGER);
   myAlgorithm.run(graph, property);

   graph = session.read_graph_by_name('bg_py_view', 'pg_view')
   property = graph.create_vertex_property("integer")
   my_algorithm.run(graph, property)
   {'success': True, 'canceled': False, 'exception': None, 'return_value': 42, 'execution_time(ms)': 1}