Name: rlT66838 Date: 08/18/97


When using Statement.execute to run a SELECT that returns a VARBINARY field containing data that is about 6K or
longer, the data returned is not the proper data. The byte array is the right length, but the data starts off with data
that seems to be from the end of the binary data.
   
I tried both SQL Server and Sybase SQL Anywhere databases. In order to ensure that it wasn't my ODBC causing
problems, I also ran a C program using ODBC directly, and it worked correctly.
   
The following program can be used to demonstrate the problem.--You need to set up an ODBC data source called
CanScanData.
=====PROGRAM FOLLOWS=======
import java.sql.*;

public class TestAny
{
public static void main(String args[])
{
Connection con = null;
Driver d;
try
{
d = (Driver)Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();
} catch (Exception e)
{
System.out.println(e);
return;
}

try
{
con = DriverManager.getConnection("jdbc:odbc:" + "CanScanData","csu","a");
} catch(Exception e)
{
System.out.println(e);
return;
}

SQLWarning warning = null;
try
{
warning = con.getWarnings();

if (warning == null)
{
System.out.println("No Warnings");
}
else
{
while (warning != null)
{
System.out.println("Warning: "+warning);
warning = warning.getNextWarning();
}
}
} catch (Exception e)
{
System.out.println(e);
}
Statement stmt = null;
try
{
stmt = con.createStatement();
} catch (Exception e)
{
System.out.println(e);
}

boolean ret = false;
ResultSet results = null;
int updateCount = 0;

try
{
ret = stmt.execute("Create Table FinishedScans (ScanDoneID integer, ScanID integer, Picture LONG BINARY)");
if (ret == true)
{
results = stmt.getResultSet();
try
{
ResultSetMetaData rsmd = results.getMetaData();
System.out.println(rsmd.getColumnTypeName(3) + " type " + rsmd.getColumnType(3) + " size " + rsmd.getColumnDisplaySize(3));
}
catch (Exception e)
{
System.out.println("meta data error");
}
}
else
{
updateCount = stmt.getUpdateCount();
}
} catch(Exception e)
{
System.out.println(e);
}

// DriverManager.setLogStream(System.out);

PreparedStatement pstmt;

try
{
pstmt = con.prepareStatement("INSERT INTO FinishedScans(ScanID, Picture) VALUES(?, ?)");

//If the following size is set to 6000, value does not get read back correctly--yet it does at 5100
//int sizeOfData = 5100;
int sizeOfData = 6000;
byte []bvalue = new byte[sizeOfData];
int p;
{
for (p = 0; p < 10; p++)
bvalue[p] = (byte)p;
for (p = 10; p < sizeOfData/3; p++)
bvalue[p] = (byte)0;
for (p = sizeOfData/3; p < (sizeOfData/3)*2; p++)
bvalue[p] = (byte)p;
for (p = (sizeOfData/3)*2; p < sizeOfData; p++)
bvalue[p] = (byte)(((p & 1) != 0) ? 0xBE : 0xEF);
int j;
for (j = 0; j < java.lang.Math.min(bvalue.length, 40); j++)
System.out.print(bvalue[j] + " ");
System.out.println();
}
System.out.println("Assigning ScanID value");
pstmt.setInt(1, 2);
System.out.println("Assigning byte[] value");
pstmt.setObject(2, bvalue, Types.LONGVARBINARY);

System.out.println("Made it to execute");
ret = pstmt.execute();
}
catch (Exception e)
{
System.out.println("prepareStatement returned " + e);
}

try
{
ret = stmt.execute("SELECT * FROM FinishedScans");
if (ret == true)
{
results = stmt.getResultSet();
try
{
ResultSetMetaData rsmd = results.getMetaData();
System.out.println(rsmd.getColumnTypeName(3) + " type " + rsmd.getColumnType(3) + " size " + rsmd.getColumnDisplaySize(3));
}
catch (Exception e)
{
System.out.println("meta data error");
}
}
else
{
updateCount = stmt.getUpdateCount();
}
} catch(Exception e)
{
System.out.println(e);
}

try
{
int rowcount = 0;
int i;
while (results.next() && rowcount < 100)
{
for (i=1; i <= 3; i++)
{
if (i==3)
{
byte []rvalue = results.getBytes(i);
int j;
for (j = 0; j < java.lang.Math.min(rvalue.length, 40); j++)
System.out.print(rvalue[j] + " ");
System.out.println();
System.out.println("size of array is " + rvalue.length);
}
else
{
try
{
System.out.println(results.getObject(i).toString());
}
catch (Exception e)
{
System.out.println(e);
}
}
}
rowcount++;
}
results.close();
}
catch (Exception e)
{
System.out.println("Print value returned " + e);
}
try
{
ret = stmt.execute("DELETE FROM FinishedScans WHERE ScanID = 2");
}
catch (Exception e)
{
System.out.println("error deleting " + e);
}

try
{
ret = stmt.execute("Drop Table FinishedScans");
} catch(Exception e)
{
System.out.println(e);
}
}
}


======================================================================


daniel.indrigo@Canada 1998-04-02

Got another report, this time including the fix. It looks like we keep overwriting the same byte array rather than creating new ones to add to the hash table

"When obtaining data larger than 5k bytes through JDBC-ODBC bridge,
the contents of the data collapsed. This may be the duplicate of
jdbc/4072639. We believe that applying the following patch to
share/sun/sun/jdbc/odbc/JdbcOdbcResultSet.java will solve the problem
in JDK1.1.6K, to say the least.
 
707a708
> b = new byte[maxLen];"