[HACKERS] Problem with move not returning number of rows affected [was: errorwhen using move, any suggestions?]

Barry Lind Tue, 24 Dec 2002 09:29:26 -0800

Noel,

I now understand why this is failing. The following code in QueryExecutor.java is having problems:

if (status.startsWith("INSERT") || status.startsWith("UPDATE") || status.startsWith("DELETE") || status.startsWith("MOVE"))
{
update_count = Integer.parseInt(status.substring(1 + status.lastIndexOf(' ')));
}

The code is expecting the server to return the keyword MOVE followed by the number of rows actually moved. And on all tests on my databases this is always true, move is followed by a number. However from the information you have provided, it seems that on your database the server is just returning MOVE without the row count. At first pass this appears to be a bug in the server. What platform are you running on?

Now the driver could be changed to handle this case, but I'm not exactly sure what no value in this case should mean? perhaps 0?

I am cc'ing the hackers mail list to see if perhaps I misunderstand how the protocol between client and server is supposed to work in this case.

thanks,
--Barry

Noel wrote:

Dave,

Many thanks for your time. Unfortunalty, I'm still getting the same error, even with the code you send, modified to use my database.

import blastDb.*;
import java.sql.*;
import java.io.*;
import java.util.*;
import java.lang.*;

public class TestFetchSize{
public static void main(String[] args){
Connection connection = null;
ResultSet rs;
try{
connection = new BlastDB().connection;
connection.setAutoCommit(false); Statement stmt = connection.createStatement();
int counte = 0;
int result = stmt.executeUpdate("declare test cursor for select id from region " +
"where protein_database = 1");
System.out.println("Cursor created, result is: " + result);
result = stmt.executeUpdate("move forward 99 in test");
System.out.println("Moved 99, result is: " + result);
while(true){
rs = stmt.executeQuery("fetch forward 2 in test");
if (rs.next()){
++counte;
while (rs.next()){
++counte;
System.out.println("Id --> " + rs.getObject(1).toString());
}
}
else
break;
}
System.out.println(counte);
rs.close();
connection.commit();
connection.close();
}
catch (Exception e) {
e.printStackTrace();
System.out.println(e.getMessage());
}
finally{
try{
if(null != connection)
connection.close();
}
catch(Exception e) {}
}
}
}

With the move statement commented out it works fine.
The database is running on an IBM server with 4 Intel(R) Xeon(TM) CPU 1.40GHz.
The programe is running on a 1.2Ghz Athon machine with debin linux and 1Gig Ram.
I don't know if this helps at all.
Is there anyother info which may help you??
Once again many thanks for your help.
Noel

Noel,

Ok, I have some test code that works

public CursorTest()
{
Connection con = null;
ResultSet rs;
try{
con = getConnection();
con.setAutoCommit( false );
Statement stmt = con.createStatement();

int result = stmt.executeUpdate( "declare test cursor for select *
from orders" );
System.out.println( "Created cursor, result is " + result );
result = stmt.executeUpdate( "move 5 in test");
System.out.println( "Moved " + result );
for(;;)
{
rs = stmt.executeQuery("fetch forward 5 in test");
if ( !rs.next() )
break;
}

while(rs.next()){
System.out.println("Id -->" + rs.getObject(1).toString());
}
rs.close();
con.commit();
con.close();
}catch (Exception ex){
ex.printStackTrace();
}finally{
try{
if (null != con) con.close();
}catch(Exception ex){}
}
}

note the fetch is actually going to return the result set, so you have
to do rs=executeQuery( "fetch ..." )

Dave
On Thu, 2002-12-19 at 19:48, Noel wrote:

Dave,
Thanks for taking the time to look at the problem. I tried the stmt.executeUpdate. It also gave the same error.

Once again, thanks
Noel

Noel,

Ok, sorry, jdbc is getting in the way here. I haven't got time right
now, so if you can't wait try changing the stmt.execute to
stmt.executeUpdate, and see what happens. I will try to figure it out
later though.

Dave
On Wed, 2002-12-18 at 23:51, Noel wrote:

Hi Dave,

I modified the small program to reflect the statement I performed in psql:

import blastDb.*;
import java.sql.*;
import java.io.*;
import java.util.*;
import java.lang.*;

public class TestFetchSize
{
public static void main(String[] args)
{
try
{
BlastDB db = new BlastDB();
Statement stmt = db.connection.createStatement();
int counte = 0;
stmt.execute("begin work");
stmt.execute("declare test cursor for select id from region where protein_database = 1");
ResultSet rs;
System.out.println("here1");
stmt.execute("move forward 99 in test");
System.out.println("here2");
while(stmt.execute("fetch forward 2 in test"))
{
rs = stmt.getResultSet();
if (rs.next())
{
++counte;
while (rs.next())
{
++counte;
}
}
else
break;
}

rs = stmt.getResultSet();
if (rs.next())
System.out.println("ok");
else
System.out.println("NO");
System.out.println(counte);
stmt.execute("end work");
}
catch (Exception e)
{
e.printStackTrace();
System.out.println(e.getMessage());
}
}
}

This is the out put, the same error as before :(
here1
Unable to fathom update count MOVE
at org.postgresql.core.QueryExecutor.receiveCommandStatus(QueryExecutor.java:182)
at org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:80)
at org.postgresql.Connection.ExecSQL(Connection.java:398)
at org.postgresql.jdbc2.Statement.execute(Statement.java:130)
at TestFetchSize.main(TestFetchSize.java:21)
Unable to fathom update count MOVE

So the programe is not moving beyound the move statement.

Many thanks
Noel

P.S. Is this sim to the INSERT problem with the sim error message?

Dave Cramer wrote:

Noel,

Well, your sql in the driver was fetch forward 2000 in test, does that
work?

It shouldn't be a driver error, the driver just passes sql through.

Dave
On Wed, 2002-12-18 at 20:51, Noel Faux wrote:

Hi Dave,

It works fine in psql:
blast=# begin;
BEGIN
blast=# declare test cursor for select id from region where
protein_database = 1;
SELECT
blast=# move forward 99 in test;
MOVE
blast=# fetch forward 2 in test;
id
--------
486175
481881
(2 rows)

Is this a driver error?
Thanks for your reply
Cheers
Noel

Noel Faux
Department of Biochemistry and Molecluar Biology
Monash University
Clayton 3168
Victoria
Australia

----- Original Message -----
From: Dave Cramer <[EMAIL PROTECTED]>
Date: Wednesday, December 18, 2002 9:43 pm
Subject: Re: [JDBC] error when using move, any suggestions?

Noel,

What do you get from the server when you try the same commands in psql?
I just tried it and it works fine?

test=# begin;
BEGIN
test=# declare test cursor for select id from address ;
DECLARE CURSOR
test=# move forward 99 in test;
MOVE 1
test=# fetch forward 2000 in test;
id
----
(0 rows)

Dave

On Wed, 2002-12-18 at 00:30, Noel wrote:

Hi all,
I'm new to postgreSQL.
I wrote a little test program to learn how to use fetch and move
in

postgreSQL.

import blastDb.*;
import java.sql.*;
import java.io.*;
import java.util.*;
import java.lang.*;

public class TestFetchSize
{
public static void main(String[] args)
{
try
{
BlastDB db = new BlastDB();
Statement stmt =db.connection.createStatement();
int counte = 0;
stmt.execute("begin work");
stmt.execute("declare test cursor for select id
from region where

protein_database = 1");
ResultSet rs;
stmt.execute("move forward 99 in test");
while(stmt.execute("fetch forward 2000 in test"))
{
rs = stmt.getResultSet();
if (rs.next())
{
++counte;
while (rs.next())
{
++counte;
}
}
else
break;
}
System.out.println(counte);
stmt.execute("end work");
}
catch (Exception e)
{
e.printStackTrace();
System.out.println(e.getMessage());
}
}
}

It compiles ok, however when run i get this message:
Unable to fathom update count MOVE
at

org.postgresql.core.QueryExecutor.receiveCommandStatus(QueryExecutor.java:182)>
at org.postgresql.core.QueryExecutor.execute(QueryExecutor.java:80)

at org.postgresql.Connection.ExecSQL(Connection.java:398)
at org.postgresql.jdbc2.Statement.execute(Statement.java:130)
at TestFetchSize.main(TestFetchSize.java:25)
Unable to fathom update count MOVE

I've search the web and the archives, and the only thing close
is the

thread about a sim problem with INSERT:
"Basically the driver was storing the oid in an int. The value
you have

is overflowing the value allowed for a signed int.

thanks,
--Barry "

Is this the same problem ?
Using 7.4 divers with JDBC3 support.

Cheers
Noel

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[HACKERS] Problem with move not returning number of rows affected [was: errorwhen using move, any suggestions?]

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