//lcawley Verified example output 2017-04-11
[[ml-datafeed-resource]]
==== Data Feed Resources

A data feed resource has the following properties:

`aggregations`::
  (object) If set, the data feed performs aggregation searches.
  For syntax information, see {ref}/search-aggregations.html[Aggregations].
  Support for aggregations is limited and should only be used with
  low cardinality data.
  For example:
  `{"@timestamp": {"histogram": {"field": "@timestamp",
  "interval": 30000,"offset": 0,"order": {"_key": "asc"},"keyed": false,
  "min_doc_count": 0}, "aggregations": {"events_per_min": {"sum": {
  "field": "events_per_min"}}}}}`.

//TBD link to a Working with aggregations page
`chunking_config`::
  (object) Specifies how data searches are split into time chunks.
  See <<ml-datafeed-chunking-config>>.
  For example: {"mode": "manual", "time_span": "3h"}

`datafeed_id`::
 (string) A numerical character string that uniquely identifies the data feed.

`frequency`::
  (time units) The interval at which scheduled queries are made while the data
  feed runs in real time. The default value is either the bucket span for short
  bucket spans, or, for longer bucket spans, a sensible fraction of the bucket
  span. For example: "150s"

`indexes` (required)::
  (array) An array of index names. For example: ["it_ops_metrics"]

`job_id` (required)::
 (string) The unique identifier for the job to which the data feed sends data.

`query`::
  (object) The {es} query domain-specific language (DSL). This value
  corresponds to the query object in an {es} search POST body. All the
  options that are supported by {es} can be used, as this object is
  passed verbatim to {es}. By default, this property has the following
  value: `{"match_all": {"boost": 1}}`.

`query_delay`::
  (time units) The number of seconds behind real time that data is queried. For
  example, if data from 10:04 a.m. might not be searchable in {es} until
  10:06 a.m., set this property to 120 seconds. The default value is `60s`.

`scroll_size`::
  (unsigned integer) The `size` parameter that is used in {es} searches.
  The default value is `1000`.

`types` (required)::
  (array) A list of types to search for within the specified indices.
  For example: ["network","sql","kpi"].

[[ml-datafeed-chunking-config]]
===== Chunking Configuration Objects

Data feeds might be required to search over long time periods, for several months
or years. This search is split into time chunks in order to ensure the load
on {es} is managed. Chunking configuration controls how the size of these time
chunks are calculated and is an advanced configuration option.

A chunking configuration object has the following properties:

`mode` (required)::
  There are three available modes: +
  `auto`::: The chunk size will be dynamically calculated. This is the default
  and recommended value.
  `manual`::: Chunking will be applied according to the specified `time_span`.
  `off`::: No chunking will be applied.

`time_span`::
  (time units) The time span that each search will be querying.
  This setting is only applicable when the mode is set to `manual`.
  For example: "3h".

[float]
[[ml-datafeed-counts]]
==== Data Feed Counts

The get data feed statistics API provides information about the operational
progress of a data feed. For example:

`assignment_explanation`::
  (string) For started data feeds only, contains messages relating to the
  selection of a node.

`datafeed_id`::
 (string) A numerical character string that uniquely identifies the data feed.

`node`::
  (object) The node upon which the data feed is started. The data feed and
  job will be on the same node.
  `id`::: The unique identifier of the node. For example,
  "0-o0tOoRTwKFZifatTWKNw".
  `name`::: The node name. For example, "0-o0tOo".
  `ephemeral_id`::: The node ephemeral ID.
  `transport_address`::: The host and port where transport HTTP connections are
  accepted. For example, "127.0.0.1:9300".
  `attributes`::: For example, {"max_running_jobs": "10"}.

`state`::
  (string) The status of the data feed, which can be one of the following values: +
  `started`::: The data feed is actively receiving data.
  `stopped`::: The data feed is stopped and will not receive data until it is
  re-started.