Foglight 7.1.0 - Web Component Tutorial

Selecting Everything except the top N may be useful in conjunction with an aggregation operation where you use one query to get an average of the top N, and you want to use another query to get an average of the rest of the data that are not in the top N.

You would almost always use Order By when you use Filter Results Based on Top N. Otherwise you would not know in which order the results would occur, and thus it would not be clear which results would be included in the top N.

Order By

Order By keys control the sorting of the data objects returned by the query.


	NOTE: Sorting is applied before Filter Results Based on Top N is applied.

You can create multiple keys. Order By sorts on the first key, then on the second key, and follows the sequence. Order By sorts only on a second key if the first key has data objects in which the values were identical. In this case Order By sorts the data objects containing those identical values based on the second key. This continues as further keys are specified.

There are three types of views that can use the query's sort order: drop-downs, row-oriented tables, and radio-buttons. As a result, sorting within a query is usually only needed when Filter Results Based on Top N is also used.


	NOTE: Row-oriented tables also have their own sorting capabilities. If used, these settings override the query's sort order.

If you are sorting on a metric property, such as cpuUsage under Hosts, the algorithm automatically sorts on the metric's current/value property.

Adding an Order By Key

To add an Order By key:

Click the

button under Order By.

A new set of input fields is added.

Select the Path from the drop-down tree.

Select ascending or descending.

Removing an Order By key

To remove an Order By key:

•

Click the

button.

Where

The Where property restricts which data objects are selected by the query, based on criteria such as property values in the data objects.


	NOTE: In SQL, the property and its parts are also called Where clauses.

Adding a Where Clause

To add a Where clause:

Click the

button under Where.

A popup appears, displaying the following types of conditions:

•

Comparison: Compare by Path, Specific value, or From Parameter with Path. Comparisons can be one of equals, not equals, is less than, is less than or equals, is greater than, is greater than or equals, like, matches or in.


	NOTE: WCF queries can evaluate comparisons in which the left side value is a list and the right side is not a list. The Evaluator iterates over all items in the list and compares each element of the list with the right-side value.

•

Is Set: Choose a path to check if it is set.

•

Sub Type is: True if the sub type of the object is as specified.

•

And: Logical operator whose operands may be any of the types in this list

•

Or: Logical operator whose operands may be any of the types in this list

•

Not: Logical operator whose operands may be any of the types in this list

Select a type and the fields that define the condition are displayed.

Any condition evaluates to either true or false. The conditions in the Where clause are evaluated for each data object found by the query. That data object is included in the final results only if the condition evaluates to true.