Creating a Grafana dashboard and panel

Grafana is organized into ‘Dashboards' and ‘Panels'. A dashboard represents a view onto the performance of a system, and each dashboard consists of one or more panels, which represents information about a specific metric related to that system.

In this tutorial, you'll build a simple dashboard, connect it to TimescaleDB, and visualize data.

Prerequisites

To complete this tutorial, you need a cursory knowledge of the Structured Query Language (SQL). The tutorial walks you through each SQL command, but it is helpful if you've seen SQL before.

Once your installation of TimescaleDB and Grafana are complete, ingest the data found in the NYC Taxi Cab tutorial and configure Grafana to connect to that database. Be sure to follow the full tutorial if you're interested in background on how to use TimescaleDB.

Build a new dashboard

Start by creating a new dashboard. In the far left of the Grafana user interface, you'll see a '+' icon. If you hover over it, you'll see a 'Create' menu, within which is a 'Dashboard' option. Select that 'Dashboard' option.

After creating a new dashboard, you'll see a 'New Panel' screen, with options for 'Add Query' and 'Choose Visualization'. In the future, if you already have a dashboard with panels, you can click on the '+' icon at the top of the Grafana user interface, which enables you to add a panel to an existing dashboard.

To proceed with our tutorial, let's add a new visualization by clicking on the 'Choose Visualization' option.

At this point, you'll have several options for different Grafana visualizations. Choose the first option, the 'Graph' visualization.

There are multiple ways to configure our panel, but you can accept all the defaults and create a simple 'Lines' graph.

In the far left section of the Grafana user interface, select the 'Queries' tab.

Instead of using the Grafana query builder, edit the query directly. In the view, click on the 'Edit SQL' button at the bottom.

Before we can begin authoring our query, we also want to set the Query database to the New York City taxi cab datasource we connected to earlier:

Visualize metrics stored in TimescaleDB

Let's start by creating a visualization that answers the question How many rides took place on each day? from the NYC Taxi Cab tutorial.

From the tutorial, you can see the standard SQL syntax for our query:

SELECT date_trunc('day', pickup_datetime) AS day,
  COUNT(*)
FROM rides
GROUP BY day
ORDER BY day;

We need to alter this query to support Grafana's unique query syntax.

Modifying the SELECT statement

First, modify the date_trunc function to use the TimescaleDB time_bucket function. You can consult the TimescaleDB API Reference on time_bucket for more information on how to use it properly.

Let's examine the SELECT portion of this query. First, bucket the results into one day groupings using the time_bucket function. If you set the 'Format' of a Grafana panel to be 'Time series', for use in Graph panel for example, then the query must return a column named time that returns either a SQL datetime or any numeric datatype representing a Unix epoch.

So, part 1 of this new query is modified so that the output of the time_bucket grouping is labeled time as Grafana requires, while part 2 is unchanged:

SELECT
  --1--
  time_bucket('1 day', pickup_datetime) AS "time",
  --2--
  COUNT(*)
FROM rides

The Grafana

Grafana time-series panels include a tool that enables the end-user to filter on a given time range, like a "time filter". Not surprisingly, Grafana has a way to link the user interface construct in a Grafana panel with the query itself. In this case, the $__timefilter() function.

In the modified query below, use the $__timefilter() function to set the pickup_datetime column as the filtering range for our visualizations.

SELECT
  --1--
  time_bucket('1 day', pickup_datetime) AS "time",
  --2--
  COUNT(*)
FROM rides
WHERE $__timeFilter(pickup_datetime)

Referencing elements in our query

Finally, we want to group our visualization by the time buckets we've selected, and we want to order the results by the time buckets as well. So, our GROUP BY and ORDER BY statements reference time.

With these changes, this is our final Grafana query:

SELECT
  --1--
  time_bucket('1 day', pickup_datetime) AS time,
  --2--
  COUNT(*)
FROM rides
WHERE $__timeFilter(pickup_datetime)
GROUP BY time
ORDER BY time

When we visualize this query in Grafana, we see the following:

tip

Remember to set the time filter in the upper right corner of your Grafana dashboard. If you're using the pre-built sample dataset for this example, you can set your time filter around January 1st, 2016.

Currently, the data is bucketed into 1 day groupings. Adjust the time_bucket function to be bucketed into 5 minute groupings instead and compare the graphs:

SELECT
  --1--
  time_bucket('5m', pickup_datetime) AS time,
  --2--
  COUNT(*)
FROM rides
WHERE $__timeFilter(pickup_datetime)
GROUP BY time
ORDER BY time

When you visualize this query, it looks like this:

Summary

Complete your Grafana knowledge by following all the TimescaleDB + Grafana tutorials.

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