Changing data services parameters to improve performance

Database services support WebSphere® Business Monitor through two data movement services: State to Runtime and Runtime to Historical. These data movement services are completely independent of each other. Each data movement service supports one or more business measures models.

For each business measures model supported by a data movement service, a set of Capture and Apply servers is created. In the current architecture, there is, by default, one Capture server and one Apply server for each business measures model. You can have more than one Capture or Apply server by changing parameters in the following parameter groups: Capture Policy Parameters, Apply Policy Parameters, and Apply Group Policy Parameters.

If the business measures models are very large, having one Capture and Apply server per model per data movement service may affect the performance and is a good candidate to benefit from modifying these parameters to improve performance. With adequate hardware and table space and buffer pool planning, it may be possible to improve performance by adding additional capture and apply servers.

Additional capture servers can increase the rate at which data is captured for the tables of a business measures model. You can decrease either or both Capture Policy Parameters. Each additional capture server will take, in return, additional database space to store its control information as well as additional processor and I/O time. However, increasing the number of servers can make information available more quickly for the Apply components and may improve the throughput of the overall system.

Additional apply servers also add another benefit. In the current architecture, apply servers operate on their assigned tables serially. The larger the number of business measures groups and tables assigned to a single apply server, the longer it takes to process all of the entries. Adding additional apply servers can improve performance by processing these business measures groups in parallel. This requires adequate hardware and a good table space and buffer pool plan to avoid I/O contention.

It is not recommended to change the defaults of the Apply Group Policy Parameters. .

How to Specify Policy Parameters:

Locate the machine hosting the Monitor Server and find the Monitor installation directory. For example: 'C:\IBM\WebSphere\Monitor' on Windows. Under this subdirectory there should be a directory called 'rm' and under that directory there should be another directory called 'config'. In this example, 'C:\IBM\WebSphere\Monitor\rm\config' would be the full path of the directory.

Create a new file called 'DS_Replication_Policy_Defaults.properties' in the config directory. If this file exists then, the Data Services components will read this file for user specified overrides of Performance Policy parameters.

Parameters are specified as follows:

During Data Movement Service processing, the system looks for service specific values first, followed by explicit default values, followed by internal or implicit default values.

Capture policy parameters

Capture policy parameters change the way that business measures groups are assigned to Capture servers. There is always one Capture server for every business measures model, but unlike the previous architecture, it is now possible to assign multiple business measures groups to the same Capture server, rather than having a separate server for each.

Apply policy parameters

Apply policy parameters change the way that business measures groups are assigned to Apply servers. At present, there is always one Apply server for every business measures model, but unlike the previous architecture, it is now possible to assign multiple business measures groups to the same Apply server, rather than having a separate server for each.

Apply Group policy parameters

These policies affect how business measures groups are allocated to Apply groups; in DB2 these are subscription sets. Refer to DB2 Replication documentation regarding the best way to allocate tables across subscription sets. Replication Manager always chooses to allocate one business measure group per subscription set.

Copyright IBM Corporation 2005. All Rights Reserved.