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iload and iunload

Rob Fisher

iload and iunload

I received the following in an E-mail from the DBA of one of my servers that I am Systems Administrator for. On these servers I am running 11.11 and he is running Informix 9.30 FC5. Has anyone seen this before?

Message from DBA:
In the last couple of weeks, I have been experiencing strange hangs when using tools I've been using, unmodified, for years. The iload and iunload tools, used to load and unload database tables, work by creating pipelines to dbaccess processes to do their work and operating in a co-process environment. Of late, the process synchronization seems to be having trouble, hanging processes and/or leaving zombies behind.
May the winds of life keep you on the right tack
Steven E. Protter
Exalted Contributor

Re: iload and iunload

Have you changed anything, loaded a new kernel? Has there been a disk issue wth the binaries?

Otherwise the DBA chould contact the binary provider for application support.

Steven E Protter
Owner of ISN Corporation
Steve Lewis
Honored Contributor

Re: iload and iunload

If they really are called iload and iunload then these are scripts that your DBA has written himself, since they are not names of standard utilities.

[dba]dev:/opt/informix/bin> ls $INFORMIXDIR/bin/i*load

As you can see, only ipload exists in the informix bin dir.

You need to ask your DBA what utilities are used within his scripts. Since you mentioned dbaccess, it sounds like he has just written simple SQLs the load and unload tables to pipe-delimited files, or named pipes.

When dbaccess hangs, it is because it cannot connect to the database server. It could be a DNS issue if his sqlhosts file and your nsswitch.conf uses host names that cause it to go off to a slow DNS server. Have firewalls been installed? Start with the name resolution, then look at the INFORMIXSERVER / hostname mapping, then the connection type / services mapping. Is it NIS?

Apart from that, have you applied any patches recently? Has he? Does informix or the server need a reboot? Or has your DBA killed a script and left a co-process running or left a control file behind?

As you can see it could be lots of things and you need to check each one in turn to find the cause.