druid/docs/content/TopNMetricSpec.md

layout
doc_page

TopNMetricSpec

The topN metric spec specifies how topN values should be sorted.

Numeric TopNMetricSpec

The simplest metric specification is a String value indicating the metric to sort topN results by. They are included in a topN query with:

"metric": <metric_value_string>

The metric field can also be given as a JSON object. The grammar for dimension values sorted by numeric value is shown below:

"metric": {
    "type": "numeric",
    "metric": "<metric_value>"
}

property	description	required?
type	this indicates a numeric sort	yes
metric	the actual metric field in which results will be sorted by	yes

Lexicographic TopNMetricSpec

The grammar for dimension values sorted lexicographically is as follows:

"metric": {
    "type": "lexicographic",
    "previousStop": "<previousStop_value>"
}

property	description	required?
type	this indicates a lexicographic sort	yes
previousStop	the starting point of the lexicographic sort. For example, if a previousStop value is 'b', all values before 'b' are discarded. This field can be used to paginate through all the dimension values.	no

AlphaNumeric TopNMetricSpec

Sort dimension values in alpha-numeric order, i.e treating numbers differently from other characters in sorting the values. See http://www.davekoelle.com/alphanum.html for details on how the algorithm works.

"metric": {
    "type": "alphaNumeric",
    "previousStop": "<previousStop_value>"
}

property	description	required?
type	this indicates an alpha-numeric sort	yes
previousStop	the starting point of the alpha-numeric sort. For example, if a previousStop value is 'b', all values before 'b' are discarded. This field can be used to paginate through all the dimension values.	no