IBM 000-8697 Manual Do Utilizador

IBM Informix OnLine Database Server Administrator’s Guide

Refer to

 for more details about how to change the value of

BUFFERS

.

If database server processes are waiting for a limited number shared-memory
resources, you can improve performance by allocating more of the needed
resource. You can eliminate waiting for an entry in the locks, tblspaces, or
users table by increasing the value of

TBLSPACES

,

LOCKS

, or

USERS

 in the

configuration file. However, each increase also increases the size of shared
memory, which is rarely an unlimited resource. You must always weigh the
positive effect of increasing OnLine shared memory against any negative
effects that might be experienced by other applications running on your host
machine.

Look at the profile of OnLine activity. A low positive number in any one of
the three fields

ovtbls

,

ovlock

, or

ovuser

 does not necessarily indicate a

need for tuning. A high value is more indicative of a need for more buffers.
If the value of

ovbuff

 exceeds 50 or 60 within a 24-hour period, begin to

monitor the field over fixed time intervals. (Use tbstat -z to set all profile
statistics to 0.) If it appears that OnLine requests consistently exceed the

BUFFERS

 value, you should attempt to tune your configuration.