Pie Chart Widget

You can use the Pie Chart widget to display a single result at a time.

See in Figure 156, “Pie Chart” an example of how this widget may look like.

Pie Chart

Figure 156. Pie Chart


Input Format

You can use the Pie Chart widget to visualize results of the groupBy() and top() functions.

If you want to display multiple aggregate results in a single chart, you can use the Bar Chart widget, which supports showing multiple aggregate results.

Or you can use the Small Multiples option supported by Pie Chart, see Example: Method Distribution in Small Multiples.

Example: Log Level Distribution

Assume we have a service producing logs like the ones below.

ini
2018-10-10T01:10:11.322Z [ERROR] Invalid User ID. errorID=2, userId=10
2018-10-10T01:10:12.172Z [WARN]  Low Disk Space.
2018-10-10T01:10:14.122Z [ERROR] Invalid User ID. errorID=2, userId=11
2018-10-10T01:10:15.312Z [ERROR] Connection Dropped. errorID=112 server=120.100.121.12
2018-10-10T01:10:16.912Z [INFO]  User Login. userId=11

We would like to show a pie chart of the relative distribution of events with the respective log levels INFO, ERROR, and WARN.

logscale
groupBy(logLevel)

If there is only one item in the pie chart, then the legend will not appear.

Example: Method Distribution in Small Multiples

The Pie Chart widget supports small multiples, which can be toggled in the settings. When grouping on more than one field, the widget can show multiple versions of itself in a grid — one for each value of a particular field. For example, you can group on HTTP requests as well as status:

logscale
groupby([method, status])

and then display a pie chart of the status distribution for each method using the Small multiples property:

Pie Chart in Small Multiples

Figure 157. Pie Chart in Small Multiples


Widget Properties

Use the widget's Edit Style panel to configure the following properties.

  • Title

    The title of the widget as displayed in the dashboard. In the example Figure 156, “Pie Chart”, the chart shows all HTTP methods, except PUT and HEAD.

  • Description

    The description of the chart. This is free form text supporting markdown syntax.

    This same description appears in the dashboard as a tooltip when hovering over the question mark on top of the widget.

  • Layout

    • Inner Radius

    Set the width of the inner circle of your pie. The width values are expressed in pixels.

    • Max Category Count

    Limit the number of slices in the pie chart. The smaller slices will be grouped into the category called Other.

  • Legends

    • Labels

      You have two options for displaying labels:

      • Truncate — shortens the length of the series for a better visualization within the chart. It is used in case of long labels that would exceed the maximum space allowed in the chart. It is the default option. Hover the mouse over a label, then press and hold ALT to momentarily see the full series.

      • Show full — shows the full name of the series, that is, the entire value is displayed in the label or tooltip. In case of very long labels, it might affect their visibility within the chart. Hover the mouse over a label, then press and hold ALT to momentarily see the truncated series.

    • Show Legend checkbox

      Allows to show or hide the legend in the pie. If ticked, it prompts the following properties.

      • Position

        Sets the position of the legend in the chart. Valid options are:

        • Right

        • Bottom

    • Visible Rows

      Text field to enter the desired number of visible rows in the legend to appear.

    • Show Title checkbox

      Allows to show or hide the legend's title.

      • Title

        Text field to enter the desired title for the legend.

  • Series

    Set the color of each series and assign each field the title you want to see displayed in the chart.

  • Small multiples

    When toggled, the query result is partitioned using the first grouping field or the specified field in the settings, and a visualization for each subresult is displayed in a grid.

    • Field name — name of the field used to partition the query result.

    • Number of columns — the number of columns in the grid. If the number of visualizations are less than the desired number of columns, the number of visualizations are used instead. If the resulting size of each visualization will be smaller than 150px, the number of columns are also overwritten by the maximum possible.

    • Show borders — allows to show or hide a border around each visualization.