The onstat command obtains and displays information stored in the shared memory tables. This includes information on users, logs, locks and other objects that are described in the shared memory structures. Some, but not all, of these structures can be seen in the sysmaster database. The onstat utility attaches directly to the shared memory.

However, unlike virtual processors, onstat does no locking on the data within shared memory. This means onstat will not delay or wait for any processes. While onstat is reading shared memory, other processes might change the memory and cause onstat to encounter a segmentation violation. When this happens, the message 'Changing data structure caused command termination'. In some cases re-submitting the command will return the correct data.


These pages are based on an article believed to be written by Troy L. Hewitt (troy@informix.com). We have added the cross referencing between commands and our own comments and views at times, but the main content is governed by the copyright of the original author.