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Do you have difficulty on finding top informix session by UNIX pid (process id)?

Background:

It is common DBA always been asked “Why informix oninit processes always in UNIX top list? What are they doing?”

In general and with common sense, if an UNIX/Linux box is hosting a (or multiple) Informix database instance(s).   Normally, most of the machine resource (CPU, memory, Disk I/O) will be consumed by Informix instance(s). Oninit processes are the daemons that serve application requests (SQL request) and interact between application and making OS system calls.

Logically, oninit processes can relate to Informix session id.  I have following steps to show how it can be done.

Note:  This may not 100% correct, as user threads are switching between CPU VPs from time to time. You may take as reference to capture repeated patterns.

Background:

I believe most of Informix users are familiar with  err -951 which sample shown belows from Informix message logs. Similar error messages are repeating frequently within a second, these will fill up the message logs file and filesystem.

#– Informix message logs –#

10:22:45  listener-thread: err = -951: oserr = 0: errstr = jsmith:
Incorrect password or user jsmith is not known on the database server.
10:22:45  listener-thread: err = -951: oserr = 0: errstr = jsmith:
Incorrect password or user jsmith is not known on the database server.

The error messages description clearly shows that there are possibilities on,

(1) Userid “jsmith”  connect with invalid password or account is locked.

(2) Userid “jsmith” is unknown or not found on database server (not found in /etc/passwd entry).

For my case, it is (2), no userid “jsmaith” found in database host.

The challenge for DBA is to find out which is remote client host attempting an invalid userid connection. Obviously, Informix message logs does not provide remote client host information.