feat: Expose ByteStreamWriter in CopyManager

pgjdbc/src/main/java/org/postgresql/copy/CopyIn.java

@@ -5,6 +5,8 @@
 
 package org.postgresql.copy;
 
+import org.postgresql.util.ByteStreamWriter;
+
 import java.sql.SQLException;
 
 /**
@@ -22,6 +24,14 @@ public interface CopyIn extends CopyOperation {
    */
   void writeToCopy(byte[] buf, int off, int siz) throws SQLException;
 
+  /**
+   * Writes a ByteStreamWriter to an open and writable copy operation.
+   *
+   * @param from the source of bytes, e.g. a ByteBufferByteStreamWriter
+   * @throws SQLException if the operation fails
+   */
+  void writeToCopy(ByteStreamWriter from) throws SQLException;
+
   /**
    * Force any buffered output to be sent over the network to the backend. In general this is a
    * useless operation as it will get pushed over in due time or when endCopy is called. Some

pgjdbc/src/main/java/org/postgresql/copy/CopyManager.java

@@ -8,6 +8,7 @@
 import org.postgresql.core.BaseConnection;
 import org.postgresql.core.Encoding;
 import org.postgresql.core.QueryExecutor;
+import org.postgresql.util.ByteStreamWriter;
 import org.postgresql.util.GT;
 import org.postgresql.util.PSQLException;
 import org.postgresql.util.PSQLState;
@@ -227,4 +228,26 @@ public long copyIn(final String sql, InputStream from, int bufferSize)
       }
     }
   }
+
+  /**
+   * Use COPY FROM STDIN for very fast copying from an ByteStreamWriter into a database table.
+   *
+   * @param sql  COPY FROM STDIN statement
+   * @param from the source of bytes, e.g. a ByteBufferByteStreamWriter
+   * @return number of rows updated for server 8.2 or newer; -1 for older
+   * @throws SQLException on database usage issues
+   * @throws IOException  upon input stream or database connection failure
+   */
+  public long copyIn(String sql, ByteStreamWriter from)
+      throws SQLException, IOException {
+    CopyIn cp = copyIn(sql);
+    try {
+      cp.writeToCopy(from);
+      return cp.endCopy();
+    } finally { // see to it that we do not leave the connection locked
+      if (cp.isActive()) {
+        cp.cancelCopy();
+      }
+    }
+  }
 }

pgjdbc/src/main/java/org/postgresql/copy/PGCopyOutputStream.java

@@ -6,6 +6,7 @@
 package org.postgresql.copy;
 
 import org.postgresql.PGConnection;
+import org.postgresql.util.ByteStreamWriter;
 import org.postgresql.util.GT;
 
 import java.io.IOException;
@@ -140,6 +141,10 @@ public void writeToCopy(byte[] buf, int off, int siz) throws SQLException {
     }
   }
 
+  public void writeToCopy(ByteStreamWriter from) throws SQLException {
+    op.writeToCopy(from);
+  }
+
   public int getFormat() {
     return op.getFormat();
   }

pgjdbc/src/main/java/org/postgresql/core/v3/CopyDualImpl.java

@@ -6,6 +6,7 @@
 package org.postgresql.core.v3;
 
 import org.postgresql.copy.CopyDual;
+import org.postgresql.util.ByteStreamWriter;
 import org.postgresql.util.PSQLException;
 
 import java.sql.SQLException;
@@ -19,6 +20,10 @@ public void writeToCopy(byte[] data, int off, int siz) throws SQLException {
     queryExecutor.writeToCopy(this, data, off, siz);
   }
 
+  public void writeToCopy(ByteStreamWriter from) throws SQLException {
+    queryExecutor.writeToCopy(this, from);
+  }
+
   public void flushCopy() throws SQLException {
     queryExecutor.flushCopy(this);
   }

pgjdbc/src/main/java/org/postgresql/core/v3/CopyInImpl.java

@@ -6,6 +6,7 @@
 package org.postgresql.core.v3;
 
 import org.postgresql.copy.CopyIn;
+import org.postgresql.util.ByteStreamWriter;
 import org.postgresql.util.GT;
 import org.postgresql.util.PSQLException;
 import org.postgresql.util.PSQLState;
@@ -37,6 +38,10 @@ public void writeToCopy(byte[] data, int off, int siz) throws SQLException {
     queryExecutor.writeToCopy(this, data, off, siz);
   }
 
+  public void writeToCopy(ByteStreamWriter from) throws SQLException {
+    queryExecutor.writeToCopy(this, from);
+  }
+
   public void flushCopy() throws SQLException {
     queryExecutor.flushCopy(this);
   }

pgjdbc/src/main/java/org/postgresql/core/v3/QueryExecutorImpl.java

@@ -37,6 +37,7 @@
 import org.postgresql.jdbc.AutoSave;
 import org.postgresql.jdbc.BatchResultHandler;
 import org.postgresql.jdbc.TimestampUtils;
+import org.postgresql.util.ByteStreamWriter;
 import org.postgresql.util.GT;
 import org.postgresql.util.PSQLException;
 import org.postgresql.util.PSQLState;
@@ -1034,7 +1035,34 @@ public synchronized void writeToCopy(CopyOperationImpl op, byte[] data, int off,
       pgStream.sendChar('d');
       pgStream.sendInteger4(siz + 4);
       pgStream.send(data, off, siz);
+    } catch (IOException ioe) {
+      throw new PSQLException(GT.tr("Database connection failed when writing to copy"),
+          PSQLState.CONNECTION_FAILURE, ioe);
+    }
+  }
+
+  /**
+   * Sends data during a live COPY IN operation. Only unlocks the connection if server suddenly
+   * returns CommandComplete, which should not happen
+   *
+   * @param op   the CopyIn operation presumably currently holding lock on this connection
+   * @param from the source of bytes, e.g. a ByteBufferByteStreamWriter
+   * @throws SQLException on failure
+   */
+  public synchronized void writeToCopy(CopyOperationImpl op, ByteStreamWriter from)
+      throws SQLException {
+    if (!hasLock(op)) {
+      throw new PSQLException(GT.tr("Tried to write to an inactive copy operation"),
+          PSQLState.OBJECT_NOT_IN_STATE);
+    }
 
+    int siz = from.getLength();
+    LOGGER.log(Level.FINEST, " FE=> CopyData({0})", siz);
+
+    try {
+      pgStream.sendChar('d');
+      pgStream.sendInteger4(siz + 4);
+      pgStream.send(from);
     } catch (IOException ioe) {
       throw new PSQLException(GT.tr("Database connection failed when writing to copy"),
           PSQLState.CONNECTION_FAILURE, ioe);

pgjdbc/src/test/java/org/postgresql/test/jdbc2/CopyTest.java

@@ -18,6 +18,7 @@
 import org.postgresql.copy.PGCopyOutputStream;
 import org.postgresql.core.ServerVersion;
 import org.postgresql.test.TestUtil;
+import org.postgresql.util.ByteBufferByteStreamWriter;
 import org.postgresql.util.PSQLState;
 
 import org.junit.After;
@@ -31,6 +32,7 @@
 import java.io.OutputStream;
 import java.io.PrintStream;
 import java.io.StringReader;
+import java.nio.ByteBuffer;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -210,6 +212,14 @@ public void testCopyInFromReader() throws SQLException, IOException {
     assertEquals(dataRows, rowCount);
   }
 
+  @Test
+  public void testCopyInFromByteStreamWriter() throws SQLException, IOException {
+    String sql = "COPY copytest FROM STDIN";
+    copyAPI.copyIn(sql, new ByteBufferByteStreamWriter(ByteBuffer.wrap(getData(origData))));
+    int rowCount = getCount();
+    assertEquals(dataRows, rowCount);
+  }
+
   @Test
   public void testSkipping() {
     String sql = "COPY copytest FROM STDIN";