After a database design has been implemented, but before changing the database design, you should consider the following:
Before you make changes affecting the entire database, you should review all the logical and physical design decisions. For example, when altering a table space, you should review your design decision regarding the use of SMS or DMS storage types. (See "Designing and Choosing Table Spaces".)
You must consider which environment variables (if any) need to be changed on your particular operating system. If any environment variables are changed, you need to restart the system for the new environment variables to take effect. Review whether you should reset the profile registry variables in the Global Profile registry before altering your database. You can then reset the profile registry values to those that are best suited to the new database environment. If only profile registry values have been changed, the system does not need to be restarted.
If you are planning changes to any nodegroups, you should review the contents of the node configuration file, db2nodes.cfg. When adding a new database partition to a nodegroup, you should first ensure that the database partition is one of those listed in the node configuration file. The database partition to be added to a nodegroup may already be part of another nodegroup and therefore already be in the node configuration file. If it is not, you must stop DB2, change the file by adding the new database partition information and then restart DB2. The new entry in the node configuration file takes effect the next time that DB2 is started. You should not remove the database partition entry in the node configuration file when removing a node from a nodegroup.
If you are planning changes to the database, you should review the values for the configuration parameters. Some of the values can be adjusted as part of the changes made to the database. However, just as with the initial setting of the configuration parameters, you may want to consider doing some benchmark testing to achieve optimal performance for your database. For more information on benchmark testing, see Chapter 18. "Benchmark Testing".