Add anomaly detection tests

After you install the dbt package and related configuration, you can add Elementary data tests.

Data monitors as dbt tests

Elementary is the first solution that delivers data monitoring and anomaly detection as dbt tests. Elementary dbt tests are actually data monitors that collect metrics and metadata over time. On each execution, the tests analyze the new data, compare it to historical metrics, and alert on anomalies and outliers. These tests are configured and executed like any other tests in your project.

Elementary tests can only be used with the elementary models, so you must run “dbt run —select elementary” to create the Elementary package models.

Elementary available monitors as tests

Table (model / source) tests:

elementary.table_anomalies

Executes table level monitors and anomaly detection. Specific monitors are detailed here and can be configured using the table_anomalies key. By default, the freshness test will use the timestamp_column provided. If you need to test for freshness by another column (e.g. if your table is partitioned), add the key freshness_column to the test.

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models:
  - name: < model name >
    config:
      elementary:
        timestamp_column: < timestamp column >
    tests:
      - elementary.table_anomalies:
          table_anomalies: < specific monitors, all if null >
          # optional - configure different freshness column than timestamp column
          freshness_column: < freshness_column >

elementary.dimension_anomalies

This test monitors the frequency of values in the configured dimension over time, and alerts on unexpected changes in the distribution. It is best to configure it on low-cardinality fields. The test counts rows grouped by given columns/expressions, and can be configured using the dimensions and where_expression keys.

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models:
  - name: < model name >
    config:
      elementary:
        timestamp_column: < timestamp column >
    tests:
      - elementary.dimension_anomalies:
          dimensions: < columns or sql expressions of columns >
          # optional - configure a where a expression to accurate the dimension monitoring
          where_expression: < sql expression >

elementary.all_columns_anomalies

Executes column level monitors and anomaly detection on all the columns of the table. Specific monitors are detailed here and can be configured using the all_columns_anomalies key.

Copiedversion: 2

models:
  - name: < model name >
    config:
      elementary:
        timestamp_column: < timestamp column >
    tests:
      - elementary.all_columns_anomalies:
          column_anomalies: < specific monitors, all if null >

elementary.schema_changes

Executes schema changes monitor that alerts on deleted table, deleted or added columns, or change of data type of a column.

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models:
  - name: < model name >
    config:
      elementary:
        timestamp_column: < timestamp column >
    tests:
      - elementary.schema_changes

Column test:

elementary.column_anomalies

Executes column level monitors and anomaly detection. Specific monitors are detailed here and can be configured using the column_anomalies key.

Copiedversion: 2

models:
  - name: < model name >
    config:
      elementary:
        timestamp_column: < timestamp column >
     columns:
      - name: < column name >
        tests:
          - elementary.column_anomalies:
              column_anomalies: < specific monitors, all if null >

  - name: < model name >
    ## if no timestamp is configured, elementary will monitor without time filtering
    columns:
      - name: < column name >
        tests:
          - elementary.column_anomalies:
              column_anomalies: < specific monitors, all if null >

How to configure your Elementary tests?

Elementary tests are added to models / sources / columns of your dbt project just like the native dbt tests. You can configure specific monitors under the relevant keys (otherwise all relevant monitors will run).

Elementary tests have three levels of configurations:

Test arguments - Test specific arguments.
Table configuration - Configure the timestamp column and details of a monitored table.
Global vars - Optional configuration parameters of the operation.

What happens on each test?

On each test elementary package executes the relevant monitors, and searches for anomalies by comparing to historical metrics. At the end of the dbt test run, all results and collected metrics are merged into the elementary models.

What does it mean when a test fails?

When a test fail, it means that an anomaly was detected on this metric and dataset. To learn more, refer to anomaly detection.

Where are Elementary tests results stored?

At the end of the dbt test run, all results and collected metrics are merged into the elementary models. The relevant models are:

alerts_data_monitoring - All the detected anomalies are merged to this table.
data_monitoring_metrics - All the collected metrics are merged to this table.
metrics_anomaly_score - The anomaly score calculated for all the metrics from the last 7 days.

Alerts on detected anomalies (failed tests)

To get Slack notifications, refer to the Slack integration.

​Data monitors as dbt tests

​Elementary available monitors as tests

​Table (model / source) tests:

​Column test:

​How to configure your Elementary tests?

​What happens on each test?

​What does it mean when a test fails?

​Where are Elementary tests results stored?

​Alerts on detected anomalies (failed tests)