Prototype based on blackhole_fdw and c -> java calls

pljava-api/src/main/java/org/postgresql/pljava/fdw/FDWForeignDataWrapper.java

@@ -0,0 +1,5 @@
+package org.postgresql.pljava.fdw;
+
+public interface FDWForeignDataWrapper {
+	FDWServer getServer();
+}

pljava-api/src/main/java/org/postgresql/pljava/fdw/FDWForeignTable.java

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+package org.postgresql.pljava.fdw;
+
+public interface FDWForeignTable {
+	FDWPlanState newPlanState();
+	FDWScanState ScanState();
+
+	default boolean updatable() { return false; }
+
+	default void analyze() { };
+//
+//	default void vacuum() { };
+}

pljava-api/src/main/java/org/postgresql/pljava/fdw/FDWPlanState.java

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+package org.postgresql.pljava.fdw;
+
+public interface FDWPlanState {
+	void open();
+
+	void close();
+
+	// int rows();
+}

pljava-api/src/main/java/org/postgresql/pljava/fdw/FDWScanState.java

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+package org.postgresql.pljava.fdw;
+
+public interface FDWScanState {
+	void open();
+	void next(Object slot);
+	void reset();
+	void close();
+
+	// void explain(); ??
+}

pljava-api/src/main/java/org/postgresql/pljava/fdw/FDWServer.java

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+package org.postgresql.pljava.fdw;
+
+import java.sql.ResultSetMetaData;
+
+public interface FDWServer {
+	FDWForeignTable getForeignTable();
+
+	// For 'importSchemaStmt()
+	ResultSetMetaData getMetaData();
+}

pljava-api/src/main/java/org/postgresql/pljava/fdw/FDWValidator.java

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+package org.postgresql.pljava.fdw;
+
+public interface FDWValidator {
+	void addOption(int relid, String key, String value);
+
+	boolean validate();
+
+	FDWForeignDataWrapper getForeignDataWrapper();
+}

pljava-examples/src/main/java/org/postgresql/pljava/example/fdw/BlackholeForeignDataWrapper.java

@@ -0,0 +1,32 @@
+package org.postgresql.pljava.example.fdw;
+
+import org.postgresql.pljava.fdw.FDWForeignDataWrapper;
+import org.postgresql.pljava.fdw.FDWServer;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.logging.Logger;
+
+/**
+ * A ForeignDataWrapper. (Persistent)
+ *
+ * Note: a single ForeignDataWrapper may contain multiple servers
+ * so there should be caching somewhere.
+ */
+public class BlackholeForeignDataWrapper implements FDWForeignDataWrapper {
+	private static final Logger LOG = Logger.getLogger(BlackholeForeignDataWrapper.class.getName());
+
+	public BlackholeForeignDataWrapper() {
+		this(Collections.emptyMap());
+	}
+
+	public BlackholeForeignDataWrapper(Map<String, String> options) {
+		LOG.info("constructor");
+	}
+
+	@Override
+	public FDWServer getServer() {
+		LOG.info("getServer()");
+		return new BlackholeServer();
+	}
+}

pljava-examples/src/main/java/org/postgresql/pljava/example/fdw/BlackholeForeignTable.java

@@ -0,0 +1,46 @@
+package org.postgresql.pljava.example.fdw;
+
+import org.postgresql.pljava.fdw.FDWForeignDataWrapper;
+import org.postgresql.pljava.fdw.FDWPlanState;
+import org.postgresql.pljava.fdw.FDWScanState;
+import org.postgresql.pljava.fdw.FDWForeignTable;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.logging.Logger;
+
+/**
+ * A Foreign Table (persistent)
+ *
+ * A single ForeignTable may have multiple PlanStates and ScanStates
+ * however they are transient and unlikely to be reused.
+ */
+public class BlackholeForeignTable implements FDWForeignTable {
+	private static final Logger LOG = Logger.getLogger(BlackholeForeignTable.class.getName());
+
+	public BlackholeForeignTable() {
+		this(Collections.emptyMap());
+	}
+
+	public BlackholeForeignTable(Map<String, String> options) {
+		LOG.info("constructor");
+	}
+
+	@Override
+	public FDWPlanState newPlanState() {
+		LOG.info("getPlanState()");
+		return new BlackholePlanState(this);
+	}
+
+	@Override
+	public FDWScanState newScanState() {
+		LOG.info("newScanState()");
+		return new BlackholeScanState(this);
+	}
+
+	@Override
+	public boolean updatable() {
+		LOG.info("updatable()");
+		return false;
+	}
+}

pljava-examples/src/main/java/org/postgresql/pljava/example/fdw/BlackholePlanState.java

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+package org.postgresql.pljava.example.fdw;
+
+import org.postgresql.pljava.fdw.FDWPlanState;
+
+import java.util.logging.Logger;
+
+/**
+ * A ForeignTable plan state. (Temporary)
+ */
+public class BlackholePlanState implements FDWPlanState {
+	private static final Logger LOG = Logger.getLogger(BlackholePlanState.class.getName());
+
+	private final BlackholeForeignTable table;
+
+	public BlackholePlanState(BlackholeForeignTable table) {
+		LOG.info("constructor()");
+		this.table = table;
+	}
+
+	@Override
+	public void open() {
+		LOG.info("open()");
+	}
+
+	@Override
+	public void close() {
+		LOG.info("close()");
+	}
+}

pljava-examples/src/main/java/org/postgresql/pljava/example/fdw/BlackholeScanState.java

@@ -0,0 +1,39 @@
+package org.postgresql.pljava.example.fdw;
+
+import org.postgresql.pljava.fdw.FDWScanState;
+
+import java.util.logging.Logger;
+
+/**
+ * A ForeignTable scan state. (Temporary)
+ */
+public class BlackholeScanState implements FDWScanState {
+	private static final Logger LOG = Logger.getLogger(BlackholeScanState.class.getName());
+
+	private final BlackholeForeignTable table;
+
+	public BlackholeScanState(BlackholeForeignTable table) {
+		LOG.info("constructor()");
+		this.table = table;
+	}
+
+	@Override
+	public void open() {
+		LOG.info("open()");
+	}
+
+	@Override
+	public void next(Object slot) {
+		LOG.info("next()");
+	}
+
+	@Override
+	public void reset() {
+		LOG.info("reset()");
+	}
+
+	@Override
+	public void close() {
+		LOG.info("close()");
+	}
+}

pljava-examples/src/main/java/org/postgresql/pljava/example/fdw/BlackholeServer.java

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+package org.postgresql.pljava.example.fdw;
+
+import org.postgresql.pljava.fdw.FDWForeignTable;
+import org.postgresql.pljava.fdw.FDWServer;
+
+import java.sql.ResultSetMetaData;
+import java.util.Collections;
+import java.util.Map;
+import java.util.logging.Logger;
+
+/**
+ * A Foreign Server (persistent)
+ *
+ * Note: a single Server may contain multiple ForeignTables
+ * so there should be caching somewhere.
+ */
+public class BlackholeServer implements FDWServer {
+	private static final Logger LOG = Logger.getLogger(BlackholeServer.class.getName());
+
+	public BlackholeServer() {
+		this(Collections.emptyMap());
+	}
+
+	public BlackholeServer(Map<String, String> options) {
+		LOG.info("constructor()");
+	}
+
+	@Override
+	public FDWForeignTable getForeignTable() {
+		LOG.info("getForeignTable()");
+		return new BlackholeForeignTable() {};
+	}
+
+	@Override
+	public ResultSetMetaData getMetaData() {
+		LOG.info("getMetaData()");
+		return null;
+	}
+}

pljava-examples/src/main/java/org/postgresql/pljava/example/fdw/BlackholeValidator.java

@@ -0,0 +1,47 @@
+package org.postgresql.pljava.example.fdw;
+
+import org.postgresql.pljava.fdw.FDWForeignDataWrapper;
+import org.postgresql.pljava.fdw.FDWValidator;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.logging.Logger;
+
+public class BlackholeValidator implements FDWValidator {
+	private static final Logger LOG = Logger.getLogger(BlackholeValidator.class.getName());
+
+	// note: we know there's only five possible integer values.
+	private final Map<Integer, Map<String, String>> options = new HashMap<>();
+
+	public BlackholeValidator() {
+		this(Collections.emptyMap());
+	}
+
+	public BlackholeValidator(Map<String, String> options) {
+		LOG.info("constructor");
+	}
+
+	@Override
+	public void addOption(int relid, String key, String value) {
+		LOG.info(String.format("addOption(%d, %s, %s)", relid, key, value));
+
+		if (!options.containsKey(relid)) {
+			options.put(relid, new HashMap<>());
+		}
+
+		options.get(relid).put(key, value);
+	}
+
+	@Override
+	public boolean validate() {
+		LOG.info("validate()");
+		return true;
+	}
+
+	@Override
+	public FDWForeignDataWrapper getForeignDataWrapper() {
+		LOG.info("getForeignDataWrapper()");
+		return new BlackholeForeignDataWrapper();
+	}
+}

pljava-so/Dockerfile

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+# TODO: pull various VERS from the environment...
+
+FROM postgres:17.2-bookworm
+LABEL authors="Bear Giles <bgiles@coyotesong.com>"
+
+ENV TARGET=target
+ENV RESOURCES=src/main/resources
+
+# can/should be set as build property...
+ENV PG_VERS=17
+ENV LIBDIR=/usr/lib/postgresql/${PG_VERS}/lib
+ENV EXTDIR=/usr/share/postgresql/${PG_VERS}/extension
+
+ENV SO_NAME=pljava.so
+
+ENV FDW_NAME=blackhole_fdw
+ENV FDW_VERS=1.9.6
+
+# this will install the standard version. It can be updated once the docker image is running in a test environment.
+RUN apt-get update && apt-get install -y postgresql-${PG_VERS}-pljava postgresql-${PG_VERS}-pljava-dbgsym
+
+COPY ${TARGET}/${SO_NAME}.so ${LIBDIR}/${SO_NAME}.so
+
+COPY ${RESOURCES}/fdw/${FDW_NAME}.control ${EXTDIR}/
+COPY ${RESOURCES}/fdw/sql/${FDW_NAME}*.sql ${EXTDIR}/
+
+# ENTRYPOINT ["top", "-b"]

pljava-so/docker-compose.yml

@@ -0,0 +1,17 @@
+services:
+  postgresql:
+    image: blackhole:latest
+    container_name: blackhole
+    ports:
+      - '5432:5432'
+    environment:
+      POSTGRES_PASSWORD: password
+    networks:
+      - frontend
+
+networks:
+  frontend:
+    # Specify driver options
+    driver: bridge
+    driver_opts:
+      com.docker.network.bridge.host_binding_ipv4: "127.0.1.1"