Monitor the shared-memory segments to determine the number and size of the segments that the database server creates. The database server allocates shared-memory segments dynamically, so these numbers can change. If the database server is allocating too many shared-memory segments, you can increase the SHMVIRTSIZE configuration parameter. For more information, see the chapter on configuration parameters in the IBM Informix: Administrator's Reference.
The onstat -g seg command lists information for each shared-memory segment, including the address and size of the segment. Figure 43 shows sample output.
Segment Summary: (resident segments are not locked) id key addr size ovhd class blkused blkfree 300 1381386241 400000 614400 800 R 71 4 301 1381386242 496000 4096000 644 V 322 178