Administration Guide

Appendix D. Memory Usage for DB2 Universal Database Version 5

The following chart presents in summary form the recommended minimum amounts of memory (in megabytes) for each of the editions and features associated with DB2 Universal Database Version 5. The base values include five (5) connections, and in each case, the value given is a liberal amount; the edition or feature will run with less memory, but performance may suffer due to paging.

When multiple editions or features are installed on the same machine (for example, Enterprise and Connect Enterprise), use the highest applicable "Base" as the base amount, and add the "Each Additional" requirement for each edition or feature as required.

Edition/Feature	Platform	Base	Each Additional	Notes
Personal	OS/2, Windows NT	32		(1)
Workgroup	OS/2, Windows NT	32	0.8	(2), (3)
Enterprise	OS/2, Windows NT	32	0.8	(2), (3)
Administration Client	OS/2, Windows NT	24
Workgroup	UNIX	64	1.6	(2), (3)
Enterprise	UNIX	64	1.6	(2), (3)
Extended Enterprise	UNIX	256	2	(4)
Connect Personal	OS/2, Windows NT	24		(5)
Connect Enterprise	OS/2, Windows NT	64	0.2
Connect Enterprise	UNIX	64	0.4
Additional Instance	All		1	(6)
Additional Database	All		2	(6)

Notes:

1. This Base value assumes a "light" application and one small database running on the machine. More than 32MB will be required in some situations.

2. The additional memory values apply to each complex, remote dynamic SQL or CLI application running on the system, above and beyond the base number of connections. Simple, remote static SQL applications require as little as one-eighth the values shown above. Local applications can vary widely in memory requirements, but generally you should allow approximately twenty percent more than the corresponding remote requirement.

3. When intra-partition parallelism is used on the database server, the number of subagents created has a significant effect on memory consumption. If the majority of the activity on the machine makes use of the intra-partition parallelism capabilities, we recommend that the base amount be doubled. The additional amount per connection should be 0.7MB plus 128K per subagent (for OS/2, Windows NT); or, 1.3MB plus 256K per subagent (for UNIX). The number of subagents would be the average of all numbers of subagents across all the database server connections.

4. The Base value is per partition. The "Each Additional" value is also per partition, and assumes a typical amount of parallelism activated by DB2 for each connection within that partition.

5. 24MB is recommended for Windows NT. 16MB is normally sufficient for Windows 95 and OS/2. These figures assume a "light" application running on the machine; it is not unusual for some applications to require 32MB.

6. The additional memory for each instance or database assumes that the default configuration parameters are in use. Settings of parameters such as BUFFPAGE can consume very large amounts of additional memory.

Regarding the amount of memory required for DB2 clients: The maximum size is approximately 2MB. However, this size could be significantly less depending on your platform; or more, depending on the application overhead.

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