//lcawley Verified example output 2017-04 [[ml-start-datafeed]] ==== Start {dfeeds-cap} A {dfeed} must be started in order to retrieve data from {es}. A {dfeed} can be started and stopped multiple times throughout its lifecycle. ===== Request `POST _xpack/ml/datafeeds//_start` ===== Description NOTE: Before you can start a {dfeed}, the job must be open. Otherwise, an error occurs. When you start a {dfeed}, you can specify a start time. This enables you to include a training period, providing you have this data available in {es}. If you want to analyze from the beginning of a dataset, you can specify any date earlier than that beginning date. If you do not specify a start time and the {dfeed} is associated with a new job, the analysis starts from the earliest time for which data is available. When you start a {dfeed}, you can also specify an end time. If you do so, the job analyzes data from the start time until the end time, at which point the analysis stops. This scenario is useful for a one-off batch analysis. If you do not specify an end time, the {dfeed} runs continuously. The `start` and `end` times can be specified by using one of the following formats: + - ISO 8601 format with milliseconds, for example `2017-01-22T06:00:00.000Z` - ISO 8601 format without milliseconds, for example `2017-01-22T06:00:00+00:00` - Seconds from the Epoch, for example `1390370400` Date-time arguments using either of the ISO 8601 formats must have a time zone designator, where Z is accepted as an abbreviation for UTC time. NOTE: When a URL is expected (for example, in browsers), the `+` used in time zone designators must be encoded as `%2B`. If the system restarts, any jobs that had {dfeeds} running are also restarted. When a stopped {dfeed} is restarted, it continues processing input data from the next millisecond after it was stopped. If new data was indexed for that exact millisecond, between stopping and starting, it will be ignored. If you specify a `start` value that is earlier than the timestamp of the latest processed record, the {dfeed} continues from 1 millisecond after the timestamp of the latest processed record. ===== Path Parameters `feed_id` (required):: (string) Identifier for the {dfeed} ===== Request Body `end`:: (string) The time that the {dfeed} should end. This value is exclusive. The default value is an empty string. `start`:: (string) The time that the {dfeed} should begin. This value is inclusive. The default value is an empty string. `timeout`:: (time) Controls the amount of time to wait until a {dfeed} starts. The default value is 20 seconds. ===== Authorization You must have `manage_ml`, or `manage` cluster privileges to use this API. For more information, see <>. ===== Examples The following example starts the `datafeed-it-ops-kpi` {dfeed}: [source,js] -------------------------------------------------- POST _xpack/ml/datafeeds/datafeed-it-ops-kpi/_start { "start": "2017-04-07T18:22:16Z" } -------------------------------------------------- // CONSOLE // TEST[skip:todo] When the {dfeed} starts, you receive the following results: [source,js] ---- { "started": true } ----