cfxdm - dm:head

Get top 'n' rows

dm:head: This cfxdm tag allows the user to fetch top 'n' rows from the queried data.

dm:head syntax:

• n (optional). Specify number of top rows that need to be listed. When this argument is not specified, by default it retrieves top 10 rows.

For predictable results, use it along with dm:sort tag.

In the below example, for a reference, we are going to use VMware vROps as an extension to query the data and ingest it into dm:head tag to list top 'n' rows.

Enter the below command to select VMware vROps Datastore Summary tag (*vrops:datastore_summary). (In this example, vrops name is used as a label to identify VMware vROps extension and it's tags. The label is defined while adding the extension in cfxdx configuration file or through UI)

tag *vrops:datastore_summary

Example 1: List top 10 rows

Get the data from VMware vROps Datastore Summary tag (*vrops:datastore_summary) and list top 10 rows.

data --> dm:head

Example 2: List top 20 rows

Get the data from VMware vROps Datastore Summary tag (*vrops:datastore_summary) and list top 20 rows.

data --> dm:head n = 20

Example 3: Sort the datastore by name (in ascending order) and List top 20 rows

Get the data from VMware vROps Datastore Summary tag (*vrops:datastore_summary), sort the data by datastore column 'name' and list top 20 rows.

data --> dm:sort columns = 'name' --> dm:head n = 20