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Create data frame analytics jobs API

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Create data frame analytics jobs API

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Instantiates a data frame analytics job.

This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.

Request

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PUT _ml/data_frame/analytics/<data_frame_analytics_id>

Prerequisites

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If the Elasticsearch security features are enabled, you must have the following built-in roles and privileges:

  • machine_learning_admin
  • kibana_user (UI only)
  • source index: read, view_index_metadata
  • destination index: read, create_index, manage and index
  • cluster: monitor (UI only)

For more information, see Security privileges and Built-in roles.

Description

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This API creates a data frame analytics job that performs an analysis on the source index and stores the outcome in a destination index.

The destination index will be automatically created if it does not exist. The index.number_of_shards and index.number_of_replicas settings of the source index will be copied over the destination index. When the source index matches multiple indices, these settings will be set to the maximum values found in the source indices.

The mappings of the source indices are also attempted to be copied over to the destination index, however, if the mappings of any of the fields don’t match among the source indices, the attempt will fail with an error message.

If the destination index already exists, then it will be use as is. This makes it possible to set up the destination index in advance with custom settings and mappings.

Hyperparameter optimization
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If you don’t supply regression or classification parameters, hyperparameter optimization occurs, which sets a value for the undefined parameters. The starting point is calculated for data dependent parameters by examining the loss on the training data. Subject to the size constraint, this operation provides an upper bound on the improvement in validation loss.

A fixed number of rounds is used for optimization which depends on the number of parameters being optimized. The optimization starts with random search, then Bayesian optimization is performed that is targeting maximum expected improvement. If you override any parameters by explicitely setting it, the optimization calculates the value of the remaining parameters accordingly and uses the value you provided for the overridden parameter. The number of rounds are reduced respectively. The validation error is estimated in each round by using 4-fold cross validation.

Path parameters

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<data_frame_analytics_id>
(Required, string) Identifier for the data frame analytics job. This identifier can contain lowercase alphanumeric characters (a-z and 0-9), hyphens, and underscores. It must start and end with alphanumeric characters.

Request body

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allow_lazy_start
(Optional, boolean) Whether this job should be allowed to start when there is insufficient machine learning node capacity for it to be immediately assigned to a node. The default is false, which means that the Start data frame analytics jobs will return an error if a machine learning node with capacity to run the job cannot immediately be found. (However, this is also subject to the cluster-wide xpack.ml.max_lazy_ml_nodes setting - see Advanced machine learning settings.) If this option is set to true then the Start data frame analytics jobs will not return an error, and the job will wait in the starting state until sufficient machine learning node capacity is available.
analysis

(Required, object) The analysis configuration, which contains the information necessary to perform one of the following types of analysis: classification, outlier detection, or regression.

analysis.classification

(Required*, object) The configuration information necessary to perform classification.

Advanced parameters are for fine-tuning classification analysis. They are set automatically by hyperparameter optimization to give minimum validation error. It is highly recommended to use the default values unless you fully understand the function of these parameters.

analysis.classification.dependent_variable

(Required, string)

Defines which field of the document is to be predicted. This parameter is supplied by field name and must match one of the fields in the index being used to train. If this field is missing from a document, then that document will not be used for training, but a prediction with the trained model will be generated for it. It is also known as continuous target variable.

The data type of the field must be numeric (integer, short, long, byte), categorical (ip or keyword), or boolean.

analysis.classification.eta
(Optional, double) Advanced configuration option. The shrinkage applied to the weights. Smaller values result in larger forests which have better generalization error. However, the smaller the value the longer the training will take. For more information, about shrinkage, see this wiki article.
analysis.classification.feature_bag_fraction
(Optional, double) Advanced configuration option. Defines the fraction of features that will be used when selecting a random bag for each candidate split.
analysis.classification.maximum_number_trees
(Optional, integer) Advanced configuration option. Defines the maximum number of trees the forest is allowed to contain. The maximum value is 2000.
analysis.classification.gamma
(Optional, double) Advanced configuration option. Regularization parameter to prevent overfitting on the training dataset. Multiplies a linear penalty associated with the size of individual trees in the forest. The higher the value the more training will prefer smaller trees. The smaller this parameter the larger individual trees will be and the longer train will take.
analysis.classification.lambda
(Optional, double) Advanced configuration option. Regularization parameter to prevent overfitting on the training dataset. Multiplies an L2 regularisation term which applies to leaf weights of the individual trees in the forest. The higher the value the more training will attempt to keep leaf weights small. This makes the prediction function smoother at the expense of potentially not being able to capture relevant relationships between the features and the dependent variable. The smaller this parameter the larger individual trees will be and the longer train will take.
analysis.classification.num_top_classes
(Optional, integer) Defines the number of categories for which the predicted probabilities are reported. It must be non-negative. If it is greater than the total number of categories (in the 7.5.2 version of the Elastic Stack, it’s two) to predict then we will report all category probabilities. Defaults to 2.
analysis.classification.prediction_field_name
(Optional, string) Defines the name of the prediction field in the results. Defaults to <dependent_variable>_prediction.
analysis.classification.training_percent
(Optional, integer) Defines what percentage of the eligible documents that will be used for training. Documents that are ignored by the analysis (for example those that contain arrays with more than one value) won’t be included in the calculation for used percentage. Defaults to 100.
analysis.outlier_detection

(Required*, object) The configuration information necessary to perform outlier detection:

analysis.outlier_detection.compute_feature_influence
(Optional, boolean) If true, the feature influence calculation is enabled. Defaults to true.
analysis.outlier_detection.feature_influence_threshold
(Optional, double) The minimum outlier score that a document needs to have in order to calculate its feature influence score. Value range: 0-1 (0.1 by default).
analysis.outlier_detection.method
(Optional, string) Sets the method that outlier detection uses. If the method is not set outlier detection uses an ensemble of different methods and normalises and combines their individual outlier scores to obtain the overall outlier score. We recommend to use the ensemble method. Available methods are lof, ldof, distance_kth_nn, distance_knn.
analysis.outlier_detection.n_neighbors
(Optional, integer) Defines the value for how many nearest neighbors each method of outlier detection will use to calculate its outlier score. When the value is not set, different values will be used for different ensemble members. This helps improve diversity in the ensemble. Therefore, only override this if you are confident that the value you choose is appropriate for the data set.
analysis.outlier_detection.outlier_fraction
(Optional, double) Sets the proportion of the data set that is assumed to be outlying prior to outlier detection. For example, 0.05 means it is assumed that 5% of values are real outliers and 95% are inliers.
analysis.outlier_detection.standardization_enabled
(Optional, boolean) If true, then the following operation is performed on the columns before computing outlier scores: (x_i - mean(x_i)) / sd(x_i). Defaults to true. For more information, see this wiki page about standardization.
analysis.regression

(Required*, object) The configuration information necessary to perform regression.

Advanced parameters are for fine-tuning regression analysis. They are set automatically by hyperparameter optimization to give minimum validation error. It is highly recommended to use the default values unless you fully understand the function of these parameters.

analysis.regression.dependent_variable

(Required, string)

Defines which field of the document is to be predicted. This parameter is supplied by field name and must match one of the fields in the index being used to train. If this field is missing from a document, then that document will not be used for training, but a prediction with the trained model will be generated for it. It is also known as continuous target variable.

The data type of the field must be numeric.

analysis.regression.eta
(Optional, double) Advanced configuration option. The shrinkage applied to the weights. Smaller values result in larger forests which have better generalization error. However, the smaller the value the longer the training will take. For more information, about shrinkage, see this wiki article.
analysis.regression.feature_bag_fraction
(Optional, double) Advanced configuration option. Defines the fraction of features that will be used when selecting a random bag for each candidate split.
analysis.regression.maximum_number_trees
(Optional, integer) Advanced configuration option. Defines the maximum number of trees the forest is allowed to contain. The maximum value is 2000.
analysis.regression.gamma
(Optional, double) Advanced configuration option. Regularization parameter to prevent overfitting on the training dataset. Multiplies a linear penalty associated with the size of individual trees in the forest. The higher the value the more training will prefer smaller trees. The smaller this parameter the larger individual trees will be and the longer train will take.
analysis.regression.lambda
(Optional, double) Advanced configuration option. Regularization parameter to prevent overfitting on the training dataset. Multiplies an L2 regularisation term which applies to leaf weights of the individual trees in the forest. The higher the value the more training will attempt to keep leaf weights small. This makes the prediction function smoother at the expense of potentially not being able to capture relevant relationships between the features and the dependent variable. The smaller this parameter the larger individual trees will be and the longer train will take.
analysis.regression.prediction_field_name
(Optional, string) Defines the name of the prediction field in the results. Defaults to <dependent_variable>_prediction.
analysis.regression.training_percent
(Optional, integer) Defines what percentage of the eligible documents that will be used for training. Documents that are ignored by the analysis (for example those that contain arrays with more than one value) won’t be included in the calculation for used percentage. Defaults to 100.
analyzed_fields

(Optional, object) Specify includes and/or excludes patterns to select which fields will be included in the analysis. The patterns specified in excludes are applied last, therefore excludes takes precedence. In other words, if the same field is specified in both includes and excludes, then the field will not be included in the analysis.

The supported fields for each type of analysis are as follows:

  • Outlier detection requires numeric or boolean data to analyze. The algorithms don’t support missing values therefore fields that have data types other than numeric or boolean are ignored. Documents where included fields contain missing values, null values, or an array are also ignored. Therefore the dest index may contain documents that don’t have an outlier score.
  • Regression supports fields that are numeric, boolean, text, keyword, and ip. It is also tolerant of missing values. Fields that are supported are included in the analysis, other fields are ignored. Documents where included fields contain an array with two or more values are also ignored. Documents in the dest index that don’t contain a results field are not included in the regression analysis.
  • Classification supports fields that are numeric, boolean, text, keyword, and ip. It is also tolerant of missing values. Fields that are supported are included in the analysis, other fields are ignored. Documents where included fields contain an array with two or more values are also ignored. Documents in the dest index that don’t contain a results field are not included in the classification analysis. Classification analysis can be improved by mapping ordinal variable values to a single number. For example, in case of age ranges, you can model the values as "0-14" = 0, "15-24" = 1, "25-34" = 2, and so on. If analyzed_fields is not set, only the relevant fields will be included. For example, all the numeric fields for outlier detection.
analyzed_fields.excludes
(Optional, array) An array of strings that defines the fields that will be excluded from the analysis. You do not need to add fields with unsupported data types to excludes, these fields are excluded from the analysis automatically.
analyzed_fields.includes
(Optional, array) An array of strings that defines the fields that will be included in the analysis.
description
(Optional, string) A description of the job.
dest

(Required, object) The destination configuration, consisting of index and optionally results_field (ml by default).

index
(Required, string) Defines the destination index to store the results of the data frame analytics job.
results_field
(Optional, string) Defines the name of the field in which to store the results of the analysis. Default to ml.
model_memory_limit
(Optional, string) The approximate maximum amount of memory resources that are permitted for analytical processing. The default value for data frame analytics jobs is 1gb. If your elasticsearch.yml file contains an xpack.ml.max_model_memory_limit setting, an error occurs when you try to create data frame analytics jobs that have model_memory_limit values greater than that setting. For more information, see Machine learning settings.
source

(object) The configuration of how to source the analysis data. It requires an index. Optionally, query and _source may be specified.

index
(Required, string or array) Index or indices on which to perform the analysis. It can be a single index or index pattern as well as an array of indices or patterns.
query
(Optional, object) The Elasticsearch query domain-specific language (DSL). This value corresponds to the query object in an Elasticsearch search POST body. All the options that are supported by Elasticsearch can be used, as this object is passed verbatim to Elasticsearch. By default, this property has the following value: {"match_all": {}}.
_source

(Optional, object) Specify includes and/or excludes patterns to select which fields will be present in the destination. Fields that are excluded cannot be included in the analysis.

includes
(array) An array of strings that defines the fields that will be included in the destination.
excludes
(array) An array of strings that defines the fields that will be excluded from the destination.

Examples

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Preprocessing actions example

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The following example shows how to limit the scope of the analysis to certain fields, specify excluded fields in the destination index, and use a query to filter your data before analysis.

PUT _ml/data_frame/analytics/model-flight-delays-pre
{
  "source": {
    "index": [
      "kibana_sample_data_flights" 
    ],
    "query": { 
      "range": {
        "DistanceKilometers": {
          "gt": 0
        }
      }
    },
    "_source": { 
      "includes": [],
      "excludes": [
        "FlightDelay",
        "FlightDelayType"
      ]
    }
  },
  "dest": { 
    "index": "df-flight-delays",
    "results_field": "ml-results"
  },
  "analysis": {
  "regression": {
    "dependent_variable": "FlightDelayMin",
    "training_percent": 90
    }
  },
  "analyzed_fields": { 
    "includes": [],
    "excludes": [
      "FlightNum"
    ]
  },
  "model_memory_limit": "100mb"
}

The source index to analyze.

This query filters out entire documents that will not be present in the destination index.

The _source object defines fields in the dataset that will be included or excluded in the destination index. In this case, includes does not specify any fields, so the default behavior takes place: all the fields of the source index will included except the ones that are explicitly specified in excludes.

Defines the destination index that contains the results of the analysis and the fields of the source index specified in the _source object. Also defines the name of the results_field.

Specifies fields to be included in or excluded from the analysis. This does not affect whether the fields will be present in the destination index, only affects whether they are used in the analysis.

In this example, we can see that all the fields of the source index are included in the destination index except FlightDelay and FlightDelayType because these are defined as excluded fields by the excludes parameter of the _source object. The FlightNum field is included in the destination index, however it is not included in the analysis because it is explicitly specified as excluded field by the excludes parameter of the analyzed_fields object.

Outlier detection example

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The following example creates the loganalytics data frame analytics job, the analysis type is outlier_detection:

PUT _ml/data_frame/analytics/loganalytics
{
  "description": "Outlier detection on log data",
  "source": {
    "index": "logdata"
  },
  "dest": {
    "index": "logdata_out"
  },
  "analysis": {
    "outlier_detection": {
      "compute_feature_influence": true,
      "outlier_fraction": 0.05,
      "standardization_enabled": true
    }
  }
}

The API returns the following result:

{
    "id": "loganalytics",
    "description": "Outlier detection on log data",
    "source": {
        "index": ["logdata"],
        "query": {
            "match_all": {}
        }
    },
    "dest": {
        "index": "logdata_out",
        "results_field": "ml"
    },
    "analysis": {
        "outlier_detection": {
            "compute_feature_influence": true,
            "outlier_fraction": 0.05,
            "standardization_enabled": true
        }
    },
    "model_memory_limit": "1gb",
    "create_time" : 1562265491319,
    "version" : "7.5.2",
    "allow_lazy_start" : false
}

Regression examples

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The following example creates the house_price_regression_analysis data frame analytics job, the analysis type is regression:

PUT _ml/data_frame/analytics/house_price_regression_analysis
{
  "source": {
    "index": "houses_sold_last_10_yrs"
  },
  "dest": {
    "index": "house_price_predictions"
  },
  "analysis":
    {
      "regression": {
        "dependent_variable": "price"
      }
    }
}

The API returns the following result:

{
  "id" : "house_price_regression_analysis",
  "source" : {
    "index" : [
      "houses_sold_last_10_yrs"
    ],
    "query" : {
      "match_all" : { }
    }
  },
  "dest" : {
    "index" : "house_price_predictions",
    "results_field" : "ml"
  },
  "analysis" : {
    "regression" : {
      "dependent_variable" : "price",
      "training_percent" : 100
    }
  },
  "model_memory_limit" : "1gb",
  "create_time" : 1567168659127,
  "version" : "7.5.0",
  "allow_lazy_start" : false
}

The following example creates a job and specifies a training percent:

PUT _ml/data_frame/analytics/student_performance_mathematics_0.3
{
 "source": {
   "index": "student_performance_mathematics"
 },
 "dest": {
   "index":"student_performance_mathematics_reg"
 },
 "analysis":
   {
     "regression": {
       "dependent_variable": "G3",
       "training_percent": 70  
     }
   }
}

The training_percent defines the percentage of the data set that will be used for training the model.

Classification example

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The following example creates the loan_classification data frame analytics job, the analysis type is classification:

PUT _ml/data_frame/analytics/loan_classification
{
  "source" : {
    "index": "loan-applicants"
  },
  "dest" : {
    "index": "loan-applicants-classified"
  },
  "analysis" : {
    "classification": {
      "dependent_variable": "label",
      "training_percent": 75,
      "num_top_classes": 2
    }
  }
}
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