Okay, I have some new code in place that hopefully should work better. I

couldn't produce a full patch using cvs diff -c this time since I have
created new files and anonymous cvs usage doesn't allow you to
adds. I'm supplying the modified src/interfaces/jdbc as a tarball at :
http://www.candleweb.no/~gunnar/projects/pgsql/postgres-jdbc-2000-10-05.tgz

The new files that should be added are :

? org/postgresql/PGStatement.java
? org/postgresql/ObjectPool.java
? org/postgresql/ObjectPoolFactory.java

There is now a global static pool of free byte arrays and used byte arrays
connected to a statement object. This is the role of the new PGStatement
class. Access to the global free array is synchronized, while we rely on
the PG_Stream synchronization for the used array.

My measurements show that the perfomance boost on this code is not quite as
big as my last shot, but it is still an improvement. Maybe some of the
difference is due to the new synchronization on the global array. I think I
will look into choosing between on a connection level and global level.

I have also started experimented with improving the performance of the
various conversions. The problem here is ofcourse related handle the
various encodings. One thing I found to speed up ResultSet.getInt() a lot
was to do custom conversion on the byte array into int instead of going
through the getString() to do the conversion. But I'm unsure if this is
portable, can we assume that a digit never can be represented by more than
one byte ? It works fine in my iso-latin-8859-1 environment, but what about
other environments ? Maybe we could provide different ResultSet
implementations depending on the encoding used or delegate some methods of
the result set to an "converter class".

Check the org/postgresql/jdbc2/FastResultSet.java in the tarball above to
see the modified getInt() method.

Regards,

        Gunnar

src/interfaces/jdbc/org/postgresql/Connection.java

@@ -10,7 +10,7 @@ import org.postgresql.largeobject.*;
 import org.postgresql.util.*;
 
 /**
- * $Id: Connection.java,v 1.6 2000/09/12 05:09:54 momjian Exp $
+ * $Id: Connection.java,v 1.7 2000/10/08 19:37:54 momjian Exp $
  *
  * This abstract class is used by org.postgresql.Driver to open either the JDBC1 or
  * JDBC2 versions of the Connection class.
@@ -81,6 +81,11 @@ public abstract class Connection
     // The PID an cancellation key we get from the backend process
     public int pid;
     public int ckey;
+
+    // This receive_sbuf should be used by the different methods
+    // that call pg_stream.ReceiveString() in this Connection, so 
+    // so we avoid uneccesary new allocations. 
+    byte receive_sbuf[] = new byte[8192];
     
     /**
      * This is called by Class.forName() from within org.postgresql.Driver
@@ -164,8 +169,9 @@ public abstract class Connection
 		// The most common one to be thrown here is:
 		// "User authentication failed"
 		//
-		throw new SQLException(pg_stream.ReceiveString
-                                       (4096, getEncoding()));
+		String msg = pg_stream.ReceiveString(receive_sbuf, 4096,
+						     getEncoding());
+		throw new SQLException(msg);
 		
 	      case 'R':
 		// Get the type of request
@@ -236,7 +242,7 @@ public abstract class Connection
 	case 'E':
 	case 'N':
            throw new SQLException(pg_stream.ReceiveString
-                                  (4096, getEncoding()));
+                                  (receive_sbuf, 4096, getEncoding()));
         default:
           throw new PSQLException("postgresql.con.setup");
       }
@@ -248,7 +254,7 @@ public abstract class Connection
 	   break;
 	case 'E':
 	case 'N':
-           throw new SQLException(pg_stream.ReceiveString(4096));
+           throw new SQLException(pg_stream.ReceiveString(receive_sbuf, 4096, getEncoding()));
         default:
           throw new PSQLException("postgresql.con.setup");
       }
@@ -263,7 +269,7 @@ public abstract class Connection
       //
       firstWarning = null;
       
-      ExecSQL("set datestyle to 'ISO'");
+      ExecSQL(null, "set datestyle to 'ISO'");
       
       // Initialise object handling
       initObjectTypes();
@@ -306,7 +312,8 @@ public abstract class Connection
 	//currentDateStyle=i+1; // this is the index of the format
 	//}
     }
-    
+
+
     /**
      * Send a query to the backend.  Returns one of the ResultSet
      * objects.
@@ -314,15 +321,18 @@ public abstract class Connection
      * <B>Note:</B> there does not seem to be any method currently
      * in existance to return the update count.
      *
+     * @param stmt The statment object.
      * @param sql the SQL statement to be executed
      * @return a ResultSet holding the results
      * @exception SQLException if a database error occurs
      */
-    public java.sql.ResultSet ExecSQL(String sql) throws SQLException
+    public java.sql.ResultSet ExecSQL(PGStatement stmt, 
+				      String sql) throws SQLException
     {
 	// added Oct 7 1998 to give us thread safety.
 	synchronized(pg_stream) {
-	    
+	    pg_stream.setExecutingStatement(stmt);
+
 	    Field[] fields = null;
 	    Vector tuples = new Vector();
 	    byte[] buf = null;
@@ -352,8 +362,7 @@ public abstract class Connection
 	    try
 		{
 		    pg_stream.SendChar('Q');
-		    buf = sql.getBytes();
-		    pg_stream.Send(buf);
+		    pg_stream.Send(sql.getBytes());
 		    pg_stream.SendChar(0);
 		    pg_stream.flush();
 		} catch (IOException e) {
@@ -370,7 +379,8 @@ public abstract class Connection
 			{
 			case 'A':	// Asynchronous Notify
 			    pid = pg_stream.ReceiveInteger(4);
-			    msg = pg_stream.ReceiveString(8192);
+			    msg = pg_stream.ReceiveString(receive_sbuf, 8192, 
+							  getEncoding());
 			    break;
 			case 'B':	// Binary Data Transfer
 			    if (fields == null)
@@ -381,7 +391,9 @@ public abstract class Connection
 				tuples.addElement(tup);
 			    break;
 			case 'C':	// Command Status
-			    recv_status = pg_stream.ReceiveString(8192);
+			    recv_status = 
+				pg_stream.ReceiveString(receive_sbuf, 8192,
+							getEncoding());
 				
 				// Now handle the update count correctly.
 				if(recv_status.startsWith("INSERT") || recv_status.startsWith("UPDATE") || recv_status.startsWith("DELETE")) {
@@ -423,7 +435,8 @@ public abstract class Connection
 				tuples.addElement(tup);
 			    break;
 			case 'E':	// Error Message
-			    msg = pg_stream.ReceiveString(4096);
+			    msg = pg_stream.ReceiveString(receive_sbuf, 4096,
+							  getEncoding());
 			    final_error = new SQLException(msg);
 			    hfr = true;
 			    break;
@@ -438,10 +451,14 @@ public abstract class Connection
 				hfr = true;
 			    break;
 			case 'N':	// Error Notification
-			    addWarning(pg_stream.ReceiveString(4096));
+			    addWarning(pg_stream.ReceiveString(receive_sbuf, 
+							       4096, 
+							       getEncoding()));
 			    break;
 			case 'P':	// Portal Name
-			    String pname = pg_stream.ReceiveString(8192);
+			    String pname = 
+				pg_stream.ReceiveString(receive_sbuf, 8192, 
+							getEncoding());
 			    break;
 			case 'T':	// MetaData Field Description
 			    if (fields != null)
@@ -461,6 +478,8 @@ public abstract class Connection
 	}
     }
 
+
+
     /**
      * Receive the field descriptions from the back end
      *
@@ -474,7 +493,8 @@ public abstract class Connection
 	
 	for (i = 0 ; i < nf ; ++i)
 	    {
-		String typname = pg_stream.ReceiveString(8192);
+		String typname = pg_stream.ReceiveString(receive_sbuf, 8192,
+							 getEncoding());
 		int typid = pg_stream.ReceiveIntegerR(4);
 		int typlen = pg_stream.ReceiveIntegerR(2);
 		int typmod = pg_stream.ReceiveIntegerR(4);