QWHERE and WHERE commands

QWHERE and WHERE are filtering mechanisms for data queries that pass through the BMC AMI Ops Infrastructure. Views and alarms use data queries to obtain the data that BMC AMI Ops monitoring products collect.

Use QWHERE and WHERE when performance or overhead is a concern due to large amounts of data being generated by a single query or by multiple repetitive queries.

Clause	Description
QWHERE	Retrieves data from a BMC AMI Ops product and filters the data before the data is returned to the requester (view, alarm or API call) Use QWHERE when a query is being driven repetitively (such as with Alarm Management) and appropriate filters will reduce the overhead of delivering the data required to satisfy the requirement.
WHERE	Retrieves data from the data returned by QWHERE and adds additional filters to the data before the data is returned to the requester (view, alarm or API call) The advantage of using WHERE is to allow multiple filters to be applied against a query set without the overhead of having to issue the query again, and without refreshing the data already in memory. Use WHERE when various filters need to be applied against a single query (such as online views that reformat data displayed to assist with problem resolution) without reissuing and refreshing the query.

Clause

Description

QWHERE

Retrieves data from a BMC AMI Ops product and filters the data before the data is returned to the requester (view, alarm or API call)

Use QWHERE when a query is being driven repetitively (such as with Alarm Management) and appropriate filters will reduce the overhead of delivering the data required to satisfy the requirement.

WHERE

Retrieves data from the data returned by QWHERE and adds additional filters to the data before the data is returned to the requester (view, alarm or API call)

The advantage of using WHERE is to allow multiple filters to be applied against a query set without the overhead of having to issue the query again, and without refreshing the data already in memory.

Use WHERE when various filters need to be applied against a single query (such as online views that reformat data displayed to assist with problem resolution) without reissuing and refreshing the query.

Example

A view such as DEVSTAT (from BMC AMI Ops Monitor for z/OS) displays every I/O device defined in the system. This view could require a very large query set and could result in unnecessary overhead. Using QWHERE DXGTYPC = 3390 limits the query set to only 3390 devices and significantly reduces the amount of data to be processed by the display manager.

After the results of the QWHERE are stored in memory, you can use WHERE to filter the stored data, without having to perform the query again.

For example, issuing the WHERE commands would not refresh the data. The data would be pulled from the existing results, saving the overhead of requesting the data again each time.

WHERE DXGSER = PROD* limits the display to 3390 devices having VOLSERs prefixed with PROD.
WHERE DXGSER = DEVL* limits the display to 3390 devices having VOLSERs prefixed with DEVL.

QWHERE and WHERE commands

BMC AMI Ops Infrastructure 7.1

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