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Druid

Druid

To add a database connection, click on the gear icon in the top right, and navigate to Admin settings > Databases > Add a database.

Fill out the fields for that database, and click Save changes at the bottom.

Select "Druid JBDC"

Prefer the Druid JDBC connection.

Settings

You can edit these settings at any time. Just remember to save your changes.

Display name

The display name for the database in the Metabase interface.

Host

Your database's IP address, or its domain name (e.g., esc.mydatabase.com).

Broker node port

The database port (e.g, 8082).

Use an SSH tunnel

See our guide to SSH tunneling.

Allow unfolding of JSON columns

Only available for the Druid JDBC connection.

This enables unfolding of JSON columns into their component fields.

See JSON unfolding.

Re-run queries for simple explorations

Turn this option OFF if people want to click Run (the play button) before applying any Summarize or filter selections.

By default, Metabase will execute a query as soon as you choose an grouping option from the Summarize menu or a filter condition from the drill-through menu. If your database is slow, you may want to disable re-running to avoid loading data on each click.

Choose when Metabase syncs and scans

Turn this option ON to manage the queries that Metabase uses to stay up to date with your database. For more information, see Syncing and scanning databases.

Database syncing

If you've selected Choose when syncs and scans happen > ON, you'll be able to set:

  • The frequency of the sync: hourly (default) or daily.
  • The time to run the sync, in the timezone of the server where your Metabase app is running.

Scanning for filter values

Metabase can scan the values present in each field in this database to enable checkbox filters in dashboards and questions. This can be a somewhat resource-intensive process, particularly if you have a very large database.

If you've selected Choose when syncs and scans happen > ON, you'll see the following options under Scanning for filter values:

  • Regularly, on a schedule allows you to run scan queries at a frequency that matches the rate of change to your database. The time is set in the timezone of the server where your Metabase app is running. This is the best option for a small database, or tables with distinct values that get updated often.
  • Only when adding a new filter widget is a great option if you want scan queries to run on demand. Turning this option ON means that Metabase will only scan and cache the values of the field(s) that are used when a new filter is added to a dashboard or SQL question.
  • Never, I'll do this manually if I need to is an option for databases that are either prohibitively large, or which never really have new values added. Use the Re-scan field values now button to run a manual scan and bring your filter values up to date.

Periodically refingerprint tables

Periodic refingerprinting will increase the load on your database.

Turn this option ON to scan a sample of values every time Metabase runs a sync.

A fingerprinting query examines the first 10,000 rows from each column and uses that data to guesstimate how many unique values each column has, what the minimum and maximum values are for numeric and timestamp columns, and so on. If you leave this option OFF, Metabase will only fingerprint your columns once during setup.

Further reading