Glean Data

The following describes in detail how we structure Glean data in BigQuery. For information on the actual software which does this, see the Generated Schemas reference.


Each ping type is recorded in its own table, and these tables are named using {application_id}.{ping_type}. For example, for Fenix, the application id is org.mozilla.fenix, so its metrics pings are available in the table org_mozilla_fenix.metrics.


Fields are nested inside BigQuery STRUCTs to organize them into groups, and we can use dot notation to specify individual subfields in a query. For example, columns containing Glean's built-in client information are in the client_info struct, so accessing its columns involves using a client_info. prefix.

The top-level groups are:

Ping and Client Info sections

Core attributes sent with every ping are mapped to the client_info and ping_info sections. For example, the client id is mapped to a column called client_info.client_id.

The metrics group

Custom metrics in the metrics section have two additional levels of indirection in their column name: they are organized by the metric type, and then by their category: metrics.{metric_type}.{category}_{name}.

For example, suppose you had the following boolean metric defined in a metrics.yaml file (abridged for clarity):

    type: boolean
    description: >
      Is this application the default browser?
      - metrics

It would be available in the column metrics.boolean.browser_is_default.

-- Count number of pings where Fenix is the default browser
  -- We give the table an alias so that the table name `metrics` and field name
  -- `metrics` don't conflict.
  org_mozilla_fenix.metrics AS m
  date(submission_timestamp) = '2019-11-11'

The events group

Custom events in the events section have a different structure.

Documentation TBD. See bug 1606836