Monitor Lakeflow Declarative Pipelines

This article describes using built-in monitoring and observability features for Lakeflow Declarative Pipelines. These features support tasks such as:

• Observing the progress and status of pipeline updates. See What pipeline details are available in the UI?.
• Alerting on pipeline events such as the success or failure of pipeline updates. See Add email notifications for pipeline events.
• Viewing metrics for streaming sources like Apache Kafka and Auto Loader (Public Preview). See View streaming metrics.
• Extracting detailed information on pipeline updates such as data lineage, data quality metrics, and resource usage. See What is the Lakeflow Declarative Pipelines event log?.
• Defining custom actions to take when specific events occur. See Define custom monitoring of Lakeflow Declarative Pipelines with event hooks.

To inspect and diagnose query performance, see Access query history for Lakeflow Declarative Pipelines. This feature is in Public Preview.

Add email notifications for pipeline events

You can configure one or more email addresses to receive notifications when the following occurs:

• A pipeline update completes successfully.
• A pipeline update fails, either with a retryable or a non-retryable error. Select this option to receive a notification for all pipeline failures.
• A pipeline update fails with a non-retryable (fatal) error. Select this option to receive a notification only when a non-retryable error occurs.
• A single data flow fails.

To configure email notifications when you create or edit a pipeline:

1. Click Add notification.
2. Enter one or more email addresses to receive notifications.
3. Click the checkbox for each notification type to send to the configured email addresses.
4. Click Add notification.

Viewing pipelines in the UI

Find your Lakeflow Declarative Pipelines from the Jobs & Pipelines option in the workspace sidebar. This opens the Jobs & pipelines page, where you can view information about each job and pipeline you have access to. Click the name of a pipeline to open the pipeline details page.

Using the Jobs & pipelines list

To view the list of pipelines you have access to, click Jobs & Pipelines in the sidebar. The Jobs & pipelines tab lists information about all available jobs and pipelines, such as the creator, the trigger (if any), and the result of the last five runs.

To change the columns displayed in the list, click and select or deselect columns.

You can filter jobs in the Jobs & pipelines list as shown in the following screenshot.

1. Text search: keyword search is supported for the Name and ID fields. To search for a tag created with a key and value, you can search by the key, the value, or both the key and value. For example, for a tag with the key department and the value finance, you can search for department or finance to find matching jobs. To search by the key and value, enter the key and value separated by a colon (for example, department:finance).
2. Type: filter by Jobs, Pipelines, or All. If you select Pipelines you can also filter by Pipeline type, which includes ETL and Ingestion pipelines.
3. Owner: show only the jobs you own.
4. Favorites: show jobs you have marked as favorites.
5. Tags: Use tags. To search by tag you can use the tags drop-down menu to filter for up to five tags at the same time or directly use the keyword search.
6. Run as: Filter by up to two run as values.

To start a job or a pipeline, click the play button. To stop a job or a pipeline, click the stop button. To access other actions, click the kebab menu . For example, you can delete the job or pipeline, or access settings for a pipeline from that menu.

What pipeline details are available in the UI?

The pipeline graph appears as soon as an update to a pipeline has successfully started. Arrows represent dependencies between datasets in your pipeline. By default, the pipeline details page shows the most recent update for the table, but you can select older updates from a drop-down menu.

Details include the pipeline ID, source code, compute cost, product edition, and the channel configured for the pipeline.

To see a tabular view of datasets, click the List tab. The List view allows you to see all datasets in your pipeline represented as a row in a table and is useful when your pipeline DAG is too large to visualize in the Graph view. You can control the datasets displayed in the table using multiple filters such as dataset name, type, and status. To switch back to the DAG visualization, click Graph.

The Run as user is the pipeline owner, and pipeline updates run with this user's permissions. To change the run as user, click Permissions and change the pipeline owner.

How can you view dataset details?

Clicking on a dataset in the pipeline graph or dataset list shows details about the dataset. Details include the dataset schema, data quality metrics, and a link to the source code defining the dataset.

View update history

To view the history and status of pipeline updates, click the update history drop-down menu in the top bar.

Select the update in the drop-down menu to view the graph, details, and events for an update. To return to the latest update, click Show the latest update.

View streaming metrics

You can view streaming metrics from the data sources supported by Spark Structured Streaming, like Apache Kafka, Amazon Kinesis, Auto Loader, and Delta tables, for each streaming flow in your Lakeflow Declarative Pipelines. Metrics are displayed as charts in the Lakeflow Declarative Pipelines UI's right pane and include backlog seconds, backlog bytes, backlog records, and backlog files. The charts display the maximum value aggregated by minute and a tooltip shows maximum values when you hover over the chart. The data is limited to the last 48 hours from the current time.

Tables in your pipeline with streaming metrics available display the icon when viewing the pipeline DAG in the UI Graph view. To view the streaming metrics, click the to display the streaming metric chart in the Flows tab in the right pane. You can also apply a filter to view only tables with streaming metrics by clicking List and then clicking Has streaming metrics.

Each streaming source supports only specific metrics. Metrics not supported by a streaming source are not available to view in the UI. The following table shows the metrics available for supported streaming sources:

What is the Lakeflow Declarative Pipelines event log?

The Lakeflow Declarative Pipelines event log contains all information related to a pipeline, including audit logs, data quality checks, pipeline progress, and data lineage. You can use the event log to track, understand, and monitor the state of your data pipelines.

You can view event log entries in the Lakeflow Declarative Pipelines user interface, the Lakeflow Declarative Pipelines API, or by directly querying the event log. This section focuses on querying the event log directly.

You can also define custom actions to run when events are logged, for example, sending alerts, with event hooks.

Event log schema

The following table describes the event log schema. Some of these fields contain JSON data that require parsing to perform some queries, such as the details field. Azure Databricks supports the : operator to parse JSON fields. See : (colon sign) operator.

Query the event log

By default, Lakeflow Declarative Pipelines writes the event log to a hidden Delta table in the default catalog and schema configured for the pipeline. While hidden, the table can still be queried by all sufficiently privileged users. By default, only the owner of the pipeline can query the event log table.

By default, the name for the hidden event log is formatted as event_log_{pipeline_id}, where the pipeline ID is the system-assigned UUID with dashed replaced by underscores.

You can interact with the JSON configuration to publish the event log. When you publish an event log, you specify the name for the event log and can optionally specify a catalog and schema, as in the following example:

{
  "id": "ec2a0ff4-d2a5-4c8c-bf1d-d9f12f10e749",
  "name": "billing_pipeline",
  "event_log": {
    "catalog": "catalog_name",
    "schema": "schema_name",
    "name": "event_log_table_name"
  }
}

The event log ___location also serves as the schema ___location for any Auto Loader queries in the pipeline. Databricks recommends creating a view over the event log table before modifying the privileges, as some compute settings might allow users to gain access to schema metadata if the event log table is shared directly. The following example syntax creates a view on an event log table, and is used in the example event log queries included in this article.

CREATE VIEW event_log_raw
AS SELECT * FROM catalog_name.schema_name.event_log_table_name;

Each instance of a pipeline run is called an update. You often want to extract information for the most recent update. Run the following query to find the identifier for the most recent update and save it in the latest_update temporary view. This view is used in the example event log queries included in this article:

CREATE OR REPLACE TEMP VIEW latest_update AS SELECT origin.update_id AS id FROM event_log_raw WHERE event_type = 'create_update' ORDER BY timestamp DESC LIMIT 1;

In Unity Catalog, views support streaming queries. The following example uses Structured Streaming to query a view defined on top of an event log table:

df = spark.readStream.table("event_log_raw")

The owner of the pipeline can publish the event log as a public Delta table by toggling the Publish event log to metastore option in the Advanced section of the pipeline configuration. You can optionally specify a new table name, catalog, and schema for the event log.

Query lineage information from the event log

Events containing information about lineage have the event type flow_definition. The details:flow_definition object contains the output_dataset and input_datasets defining each relationship in the graph.

You can use the following query to extract the input and output datasets to see lineage information:

SELECT
  details:flow_definition.output_dataset as output_dataset,
  details:flow_definition.input_datasets as input_dataset
FROM
  event_log_raw,
  latest_update
WHERE
  event_type = 'flow_definition'
  AND
  origin.update_id = latest_update.id

Query data quality from the event log

If you define expectations on datasets in your pipeline, the metrics for the number of records that passed and failed an expectation are stored in the details:flow_progress.data_quality.expectations object. The metric for the number of dropped records is stored in the details:flow_progress.data_quality object. Events containing information about data quality have the event type flow_progress.

Data quality metrics might not be available for some datasets. See the expectation limitations.

The following data quality metrics are available:

The following example queries the data quality metrics for the last pipeline update:

SELECT
  row_expectations.dataset as dataset,
  row_expectations.name as expectation,
  SUM(row_expectations.passed_records) as passing_records,
  SUM(row_expectations.failed_records) as failing_records
FROM
  (
    SELECT
      explode(
        from_json(
          details:flow_progress.data_quality.expectations,
          "array<struct<name: string, dataset: string, passed_records: int, failed_records: int>>"
        )
      ) row_expectations
    FROM
      event_log_raw,
      latest_update
    WHERE
      event_type = 'flow_progress'
      AND origin.update_id = latest_update.id
  )
GROUP BY
  row_expectations.dataset,
  row_expectations.name

Query Auto Loader events from the event log

Lakeflow Declarative Pipelines generates events when Auto Loader processes files. For Auto Loader events, the event_type is operation_progress and the details:operation_progress:type is either AUTO_LOADER_LISTING or AUTO_LOADER_BACKFILL. The details:operation_progress object also includes status, duration_ms, auto_loader_details:source_path, and auto_loader_details:num_files_listed fields.

The following example queries Auto Loader events for the latest update:

SELECT
  timestamp,
  details:operation_progress.status,
  details:operation_progress.type,
  details:operation_progress:auto_loader_details
FROM
  event_log_raw,
  latest_update
WHERE
  event_type like 'operation_progress'
  AND
  origin.update_id = latest.update_id
  AND
  details:operation_progress.type in ('AUTO_LOADER_LISTING', 'AUTO_LOADER_BACKFILL')

Monitor data backlog by querying the event log

Lakeflow Declarative Pipelines tracks how much data is present in the backlog in the details:flow_progress.metrics.backlog_bytes object. Events containing backlog metrics have the event type flow_progress. The following example queries backlog metrics for the last pipeline update:

SELECT
  timestamp,
  Double(details :flow_progress.metrics.backlog_bytes) as backlog
FROM
  event_log_raw,
  latest_update
WHERE
  event_type ='flow_progress'
  AND
  origin.update_id = latest_update.id

Monitor enhanced autoscaling events from the event log for pipelines without serverless enabled

For Lakeflow Declarative Pipelines that do not use serverless compute, the event log captures cluster resizes when enhanced autoscaling is enabled in your pipelines. Events containing information about enhanced autoscaling have the event type autoscale. The cluster resizing request information is stored in the details:autoscale object. The following example queries the enhanced autoscaling cluster resize requests for the last pipeline update:

SELECT
  timestamp,
  Double(
    case
      when details :autoscale.status = 'RESIZING' then details :autoscale.requested_num_executors
      else null
    end
  ) as starting_num_executors,
  Double(
    case
      when details :autoscale.status = 'SUCCEEDED' then details :autoscale.requested_num_executors
      else null
    end
  ) as succeeded_num_executors,
  Double(
    case
      when details :autoscale.status = 'PARTIALLY_SUCCEEDED' then details :autoscale.requested_num_executors
      else null
    end
  ) as partially_succeeded_num_executors,
  Double(
    case
      when details :autoscale.status = 'FAILED' then details :autoscale.requested_num_executors
      else null
    end
  ) as failed_num_executors
FROM
  event_log_raw,
  latest_update
WHERE
  event_type = 'autoscale'
  AND
  origin.update_id = latest_update.id

Monitor compute resource utilization

cluster_resources events provide metrics on the number of task slots in the cluster, how much those task slots are utilized, and how many tasks are waiting to be scheduled.

When enhanced autoscaling is enabled, cluster_resources events also contain metrics for the autoscaling algorithm, including latest_requested_num_executors, and optimal_num_executors. The events also show the status of the algorithm as different states such as CLUSTER_AT_DESIRED_SIZE, SCALE_UP_IN_PROGRESS_WAITING_FOR_EXECUTORS, and BLOCKED_FROM_SCALING_DOWN_BY_CONFIGURATION. This information can be viewed in conjunction with the autoscaling events to provide an overall picture of enhanced autoscaling.

The following example queries the task queue size history for the last pipeline update:

SELECT
  timestamp,
  Double(details :cluster_resources.avg_num_queued_tasks) as queue_size
FROM
  event_log_raw,
  latest_update
WHERE
  event_type = 'cluster_resources'
  AND
  origin.update_id = latest_update.id

The following example queries the utilization history for the last pipeline update:

SELECT
  timestamp,
  Double(details :cluster_resources.avg_task_slot_utilization) as utilization
FROM
  event_log_raw,
  latest_update
WHERE
  event_type = 'cluster_resources'
  AND
  origin.update_id = latest_update.id

The following example queries the executor count history, accompanied by metrics available only for enhanced autoscaling pipelines, including the number of executors requested by the algorithm in the latest request, the optimal number of executors recommended by the algorithm based on the most recent metrics, and the autoscaling algorithm state:

SELECT
  timestamp,
  Double(details :cluster_resources.num_executors) as current_executors,
  Double(details :cluster_resources.latest_requested_num_executors) as latest_requested_num_executors,
  Double(details :cluster_resources.optimal_num_executors) as optimal_num_executors,
  details :cluster_resources.state as autoscaling_state
FROM
  event_log_raw,
  latest_update
WHERE
  event_type = 'cluster_resources'
  AND
  origin.update_id = latest_update.id

Audit Lakeflow Declarative Pipelines

You can use Lakeflow Declarative Pipelines event log records and other Azure Databricks audit logs to get a complete picture of how data is being updated in Lakeflow Declarative Pipelines.

Lakeflow Declarative Pipelines uses the credentials of the pipeline owner to run updates. You can change the credentials used by updating the pipeline owner. Lakeflow Declarative Pipelines records the user for actions on the pipeline, including pipeline creation, edits to configuration, and triggering updates.

See Unity Catalog events for a reference of Unity Catalog audit events.

Query user actions in the event log

You can use the event log to audit events, for example, user actions. Events containing information about user actions have the event type user_action.

Information about the action is stored in the user_action object in the details field. Use the following query to construct an audit log of user events. To create the event_log_raw view used in this query, see Query the event log.

SELECT timestamp, details:user_action:action, details:user_action:user_name FROM event_log_raw WHERE event_type = 'user_action'

Runtime information

You can view runtime information for a pipeline update, for example, the Databricks Runtime version for the update:

SELECT details:create_update:runtime_version:dbr_version FROM event_log_raw WHERE event_type = 'create_update'