This is a known problem when running on a Linux 64-bit platform. 

ODBC driver being used from whichever vendor handle the SQLLEN value as a 32-bit value instead of a 64-bit value.

On the other hand, unixODBC and the IBM driver involved here, libcwbodbc.so, assume that a SQLLEN entity is 32-bits when running on a 64-bit platform. 

Solution
1. Please ensure you have  a recent IBM ODBC driver for ISeries (ex: iSeriesAccess-5.4.0-x.x.x86_64.rpm).

2. Then recompile the source of the UnixODBC driver manager:
- First get the source of unixODBC driver manager
- Set the environment variable export CFLAGS="-DBUILD_REAL_64_BIT_MODE"
- Now follow the guidelines on the vendor's homepage how to link unixODBCdriver manager.
iSeriesAccess ODBC driver  does not need to be recompiled if you have recent version.

3. Please check you have these parameters in your gateway init file (ex: initdg4ODBC.ORA):
HS_RPC_FETCH_REBLOCKING=OFF
HS_FDS_FETCH_ROWS=1
HS_FDS_SQLLEN_INTERPRETATION=64 

References
BUG:8215160 - DG4ODBC RETURNS INCORRECT OUTPUT SELECTING DATA FROM DB2400
NOTE:554409.1 - Datatype Conversion Error ORA-28528 Using Dg4odbc With Informix, MySQL or SQL*Server 64-bit ODBC Drivers
NOTE:1310704.1 - Receiving Ora-07445 Core Dump Hok2beg Refreshing Materialized View Using Dg4odbc and IBM iSeries ODBC Driver

 Related

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Products 
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Oracle Database Products > Oracle Database > Oracle Database > Oracle Server - Enterprise Edition 
Errors 
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ORA-28511; ORA-6512; ORA-2068 

DG4ODBC and FreeTDS ODBC Driver Gives Error: Data Source Name Not Found, And No Default Driver Specified [ID 1289422.1] 

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  Modified 03-FEB-2011     Type PROBLEM     Status PUBLISHED   

In this Document
  Symptoms
  Cause
  Solution



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Applies to: 
Oracle Server - Enterprise Edition - Version: 11.2.0.1 and later   [Release: 11.2 and later ]
Information in this document applies to any platform.

Symptoms

It is not possible to connect to SQL*Server via DG4ODBC 11.2 using the FreeTDS ODBC driver.

An error occurs:

SQL> select * from dbo.tbl_agenda@test;
select * from dbo.tbl_agenda@test
              *
ERROR at line 1:
ORA-28500: connection from ORACLE to a non-Oracle system returned this message:
[unixODBC][Driver Manager]Data source name not found, and no default driver
specified {IM002}
ORA-02063: preceding 2 lines from TEST 


Cause

The FreeTDS or  Unix ODBC driver manager are not correctly configured.

A space is  missing before or after equal sign in the ODBC.INI or ODBCINST.INI in the "Driver" line.
Example:


[SQLtest]
       Driver=FreeTDS
       Description=MS SQL Test
       Trace=No
       Server=10.2.54.28
       Database=SQLDB
       Port=1433


ODBC.INI and ODBCINST.INI must match and DG4ODBC must call the right ODBC driver manager library.


Solution

Add spaces before and after the driver name. In this example,  ODBC.INI is in /usr/local/etc


[SQLtest]
Driver = FreeTDS
Description = MS SQL Test
Trace = No
Server = 10.2.54.28
Database = SQLDB
Port = 1433

We configure the ODBCINST.INI in /usr/local/etc 


[FreeTDS] <==============name must match with the "Driver" line in ODBC.INI
Description = FreeTDS driver
Driver = /usr/local/Freetds/libtdsodbc.so
Setup = /usr/local/Freetds/libtdsodbc.so
Trace = No
TraceFile = /tmp/freetds.log
FileUsage = 1

You can see that in each file (ODBC.INI and ODBCINST.INI), we must respect  where there is a space before and after equal sign.

The best way to be sure the ODBC connection is OK before implementing DG4ODBC is to use the osql tool. This is a FreeTDS tool that traces if the right  files are accessed and correctly read.

If you forgot a space in the Driver line in ODBC.INI or ODBCINST.INI, when you use osql  to trace the ODBC connection you get an error: 


driver line incomplete for [DSN] in odbc.ini


Here is an example:

osql command is:
$osql -S <DSN> -U <Username> -P <Password>


$osql -S SQLtest -U mimi -P Password1
looking for odbc.ini and odbcinst.ini in /usr/local/etc
       reading "/home/oracle/.odbc.ini"
[SQLtest] not found in "/home/oracle/.odbc.ini"
       reading "/usr/local/etc/odbc.ini"
[SQLtest] found in "/usr/local/etc/odbc.ini"
found this section:
       [SQLtest]
       Driver=FreeTDS
       Description=MS SQL Test
       Trace=No
       Server=10.2.54.28
       Database=SQLDB
       Port=1433
looking for driver for DSN [SQLtest]
driver line incomplete for [SQLtest] in .odbc.ini
looking for driver for DSN [default]
osql: error: no driver found for [SQLtest] in .odbc.ini


Then in the LISTENER.ORA, please modify the ENV parameter:
(ENV = "LD_LIBRARY_PATH=/usr/local/lib:/usr/local/freetds/lib:/ora/11g/lib")

During the install of FreeTDS package, this command line is used:
# ./configure -with-tdsver=8.0 -with-unixODBC=/usr/local

So libodbc.so which is supposed to be called by FreeTDS is in /usr/local/lib and not in /usr/lib64

Modify the gateway init file: initarchie_test.ora
HS_FDS_CONNECT_INFO = archietest
HS_FDS_TRACE_LEVEL = ODBC
HS_FDS_SHAREABLE_NAME = /usr/local/lib/libodbc.so <==same path as in ENV variable
                                                                                              in LISTENER.ORA
HS_FDS_SUPPORT_STATISTICS=FALSE
HS_FDS_SQLLEN_INTERPRETATION=64
HS_FDS_TIMESTAMP_MAPPING=DATE
HS_LANGUAGE=AMERICAN_AMERICA.WE8ISO8859P1
set ODBCINI=/usr/local/etc/odbc.ini
set ODBCINSTINI=/usr/local/etc/odbcinst.ini

 Related



--------------------------------------------------------------------------------
Products 
--------------------------------------------------------------------------------

Oracle Database Products > Oracle Database > Oracle Database > Oracle Server - Enterprise Edition 
Errors 
--------------------------------------------------------------------------------
ORA-2063; ORA-28500