Monthly Archives: December 2010

iSeries Access 64 Bit Driver problems Segmentation Faults

Update: May 17 2016 – At common I found out that 64 bit issues should now all be resolved when using the latest PHP 5.6, the unixODBC manager 2.2.14+ and IBM i Access for Linux ODBC driver.  This was effecting PHP extension: PDO ODBC, and ODBC_* functions

PHP 5.6.x+
http://php.net/downloads.php

UnixODBC Manager
http://www.unixodbc.org/

IBM i Access ODBC Driver [for Linux] (ibm-iaccess-1.1.0.1-1.0.x86_64)
http://www-03.ibm.com/systems/power/software/i/access/linux.html

Kevin Adler’s Article from IBM
https://www.ibm.com/developerworks/ibmi/library/i-ibmi-access-client-solutions-linux/

Segmentation Fault Problem

I’ve had a lot of trouble with using the iSeries Access 64 bit odbc driver for Linux (iSeriesAccess-5.4.0-1.6.x86_64.rpm) on my RHEL linux box to connect toa  V5R4 iSeries server.  I switched back to using the 32 bit driver and saying i’ll wait until they update the 64 bit driver to work.

I was going to the PHP page and finding just a blank screen returned to the browser, which made it a pain to debug.  I found out after looking at the apache error log file in /var/log/httpd/error_log  that there were segmentation faults with the following error:

[notice] child pid XXXXX exit signal Segmentation fault (11)

To try and debug the PHP to see what causing the problem i put die(‘here’) statements in my code until i found out where the interpretor wasn’t getting to because of the seg fault.   I found out on the return of the Zend Framework’s PDO ODBC Fetchall statement the program was causing the seg fault.  I also noticed that this only occured when i had a null field in the DB2 udb for iSeries database.  The field was a char datatype.

If you’re having this problem i’d recommend just installing the 32 bit driver(iSeriesAccess-5.4.0-1.2.i386.rpm).

Debugging

Here’s how i understand requests get called in case you want to try and debug the problem:

  1. Request for page comes in from Apache
  2. PHP runs and makes db calls through  a DSN
  3. All db calls go through unixODBC manager
  4. The db call then goes through the IBM Client Access driver you have specified and executes the sql on the iSeries.
  5. If the driver has a problem with a null field it would create a segmentation fault.

Here’s a link to someone’s explanation of the problems using the 64 bit driver:

https://www.ibm.com/developerworks/forums/thread.jspa?messageID=14510046&#14510046

Need help understanding how to install the driver and setup all the linux files (/etc/odbc.ini /etc/odbcisnt.ini)

Here’s the link to the driver download

iSeries Access Linux Driver download

Remember to edit your
/etc/odbcinst.ini

[iSeries Access ODBC Driver]

Description             = iSeries Access for Linux ODBC Driver
Driver          = /opt/ibm/iSeriesAccess/lib/libcwbodbc.so
Setup           = /opt/ibm/iSeriesAccess/lib/libcwbodbcs.so
NOTE1           = If using unixODBC 2.2.11 or later and you want the 32 and 64-bit ODBC drivers to share DSN's,
NOTE2           = the following Driver64/Setup64 keywords will provide that support.
Driver64                = /opt/ibm/iSeriesAccess/lib64/libcwbodbc.so
Setup64         = /opt/ibm/iSeriesAccess/lib64/libcwbodbcs.so
Threading               = 2
DontDLClose             = 1
UsageCount              = 1

and /etc/odbc.ini

[iSeriesDSN]
Description = iSeries Access ODBC Driver DSN for iSeries
Driver = iSeries Access ODBC Driver
System = iSeriesSystemName
UserID =
Password =
Naming = 0
DefaultLibraries = QGPL
Database =
ConnectionType = 0
CommitMode = 2
ExtendedDynamic = 0
DefaultPkgLibrary = QGPL
DefaultPackage = A/DEFAULT(IBM),2,0,1,0,512
AllowDataCompression = 1
LibraryView = 0
AllowUnsupportedChar = 0
ForceTranslation = 0
Trace = 0

Giving credit to IBM for this example file

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