Technical Blog Post
Abstract
DB2LUW LOGSECOND set to -1 can cause confusing outputs in monitoring tools
Body
In DB2LUW the LOGSECOND is a database level configuration parameter which represents the total number of secondary transaction logs which the database can allocate and use.
A value "-1" represents infinite logging.
With the value of "-1" it indicates the database is configured with infinite amount of active log space.
The value "-1" can cause issues unless it's decided consciously to take care of some momentary log space need etc.
However, there is another kind of problem which could be faced by various monitoring tools which try to generate reports using the db2's configuration settings.
Thosel include various 3rd party tools as well as IBM's internal database monitoring products.
The value "-1", if not handled correctly can show different kind of outputs in various calculations which depend on the value of LOGSECOND.
Example, a value of 65535 or, FFFF etc
These are usually a defect in those tools which should be fixed in the tools itself.
There is another kind of observation which could be faced is the calculated value is represented by "-" which indicates no specific value and that usually correspond to an infinite value.
One such example,
$ db2 get db cfg for sample |grep LOGSECOND
Number of secondary log files (LOGSECOND) = 10
--------------------
52988000
Then,
$ db2 get db cfg for sample |grep LOGSECOND
Number of secondary log files (LOGSECOND) = -1
--------------------
-
This is a normal output when LOGSECOND is set to -1.
To avoid this confusion it's suggested to set the value to something specific instead of -1
UID
ibm11139908