Package org.apache.flink.table.factories

Interface CatalogStoreFactory

All Superinterfaces:
Factory
@PublicEvolving public interface CatalogStoreFactory extends Factory
A factory to create configured catalog store instances based on string-based properties. See also Factory for more information.

This factory is specifically designed for the Flink SQL gateway scenario, where different catalog stores need to be created for different sessions.

If the CatalogStore is implemented using JDBC, this factory can be used to create a JDBC connection pool in the open method. This connection pool can then be reused for subsequent catalog store creations.

The following examples implementation of CatalogStoreFactory using jdbc. 


 public class JdbcCatalogStore implements CatalogStore {

     private JdbcConnectionPool jdbcConnectionPool;
     public JdbcCatalogStore(JdbcConnectionPool jdbcConnectionPool) {
         this.jdbcConnectionPool = jdbcConnectionPool;
     }
     ...
 }

 public class JdbcCatalogStoreFactory implements CatalogStoreFactory {

     private JdbcConnectionPool jdbcConnectionPool;

     @Override
     public CatalogStore createCatalogStore(Context context) {
         return new JdbcCatalogStore(jdbcConnectionPool);
     }

     @Override
     public void open(Context context) throws CatalogException {
         // initialize the thread pool using options from context
         jdbcConnectionPool = initializeJdbcConnectionPool(context);
     }

     @Override
     public void close() {
         // release the connection thread pool.
         releaseConnectionPool(jdbcConnectionPool);
     }
     ...
 }

The usage of the Flink SQL gateway is as follows. It's just an example and may not be the final implementation. 


  // initialize CatalogStoreFactory when initialize the SessionManager
  public class SessionManagerImpl implements SessionManager {
      public SessionManagerImpl(DefaultContext defaultContext) {
        this.catalogStoreFactory = createCatalogStore();
      }

      @Override
      public void start() {
          // initialize the CatalogStoreFactory
          this.catalogStoreFactory(buildCatalogStoreContext());
      }

      @Override
      public synchronized Session openSession(SessionEnvironment environment) {
          // Create a new catalog store for this session.
          CatalogStore catalogStore = this.catalogStoreFactory.createCatalogStore(buildCatalogStoreContext());

          // Create a new CatalogManager using catalog store.
      }

      @Override
      public void stop() {
          // Close the CatalogStoreFactory when stopping the SessionManager.
          this.catalogStoreFactory.close();
      }
 }

  • Method Details

    • createCatalogStore

      CatalogStore createCatalogStore()
      Creates a CatalogStore instance from context information.

    • open

      void open(CatalogStoreFactory.Context context) throws CatalogException
      Initialize the CatalogStoreFactory.

      For the use case of Flink SQL gateway, the open method will be called when starting SessionManager. It initializes common resources, such as a connection pool, for various catalog stores.

      Throws:
      CatalogException

    • close

      void close() throws CatalogException
      Close the CatalogStoreFactory.

      For the use case of Flink SQL gateway, the close method will be called when closing SessionManager. It releases common resources, such as connection pool, after closing all catalog stores.

      Throws:
      CatalogException