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PCF query optimization for MQ server administration Disclosure Number: IPCOM000129856D
Original Publication Date: 2005-Oct-07
Included in the Prior Art Database: 2005-Oct-07
Document File: 2 page(s) / 54K

Publishing Venue



A program written to monitor the state of an IBM WebSphere MQ system issues queries in PCF (Programmable Command Format). When information about many WebSphere MQ system attributes is required, there is benefit in minimizing the number and complexity of PCF queries used. Three approaches -- subset exclusion, query merging and filter matching -- provide a means of deriving an optimized set of queries from an original query set.

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PCF query optimization for MQ server administration

An IBM* WebSphere* MQ monitoring agent monitors a target MQ queue manager, and provides notification to a client application when there are changes to the state of MQ resources such as queues, channels, or the queue manager itself. The application registers listeners specifying which resources and which attributes of those resources it should be notified about. A listener can request general notifications (e.g. of changes to any attribute of any queue) or specific notifications (e.g. of changes only to selected attributes of an individual queue).

    The monitoring agent polls the queue manager periodically to check the state of all the resources for which listeners are registered. The polling operation is relatively expensive; it involves creating a PCF (Programmable Command Format) query message, sending the query to the queue manager, and parsing one or more PCF response messages. Logically, one PCF query is associated with each registered listener. A general (wildcard) query generates one response message for each object matching the wildcard - so, the more general the query, the greater the number of responses returned. On a large system, there can be hundreds or even thousands of queues or channels; a individual wildcard query can therefore generate hundreds or thousands of responses. A general-purpose administration application may register many listeners, and polling the queue manager for all the information required may potentially involve the flow of large numbers of PCF requests and responses.

    Because of the processing overhead incurred in producing and consuming PCF request and response messages, there is a benefit in minimizing the number of messages used in gathering the overall set of information required by monitoring agent to satisfy the registered listeners. (Note: Query optimization is universally applied in database management systems, but works along entirely different lines (and has different goals) to the optimization of PCF queries.)

    The MQ monitoring agent minimizes the number of PCF request and response messages needed by eliminating queries whose results are covered by other queries, and combining multiple queries into modified single queries where possible.

    The monitoring agent combines three approaches to minimize the number of PCF request and response messages.