I'm not sure about 7.30 but it will probably work :
1. set SQLIDEBUG ebvironment variable to "2:/tmp"
2. restart server
3. check /tmp for files
4. use sqliprint utility to print communications between server and client

OR
set SQLIDEBUG for client session only (this way only that session will be monitored).


http://database.sarang.net/database/informix/faq/iiug/ifaq08.htm
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8.44 How do I log the queries informix receives?
On 28th June 1999 jleffler@earthlink.net (Jonathan Leffler) wrote:-

If you're on a civilized system (Unix or variants), and you're using a sufficiently civilized server (OnLine, IDS, etc) and a sufficiently recent version of ESQL/C (primarily CSDK 2.x), then you can set the SQLIDEBUG environment variable to a value such as 2:/tmp/sqli.out and the application will log all the data sent back and forth. You can then decipher the data with the sqliprint program. The actual data file will have an underscore and a process id after what you specified in SQLIDEBUG. The SQLIDEBUG environment variable has worked for quite some time (6.00?), but getting hold of sqliprint has been harder until it was distributed with CSDK. You can also use a value 1:/tmp/sqli.out to get some sort of ASCII dump, but it isn't as useful as the binary dump (IIRC; I've not used it more than once).