Histogram

Overview

A histogram uses vertical bars of varying heights to display data distribution based on frequency, count, or other statistics along the x-axis. Unlike a column chart, a histogram focuses on statistical analysis. Key differences:

• A histogram shows data distribution. A column chart compares values across categories.

• The x-axis of a histogram represents continuous numerical data (length, weight, time). The x-axis of a column chart represents categorical data (request methods).

• Histogram bars have little or no gap between them because the data is continuous. Column chart bars have gaps to distinguish categories.

To add a chart to a dashboard, follow the steps in Add a chart to a dashboard.

Try it out

The SLS Playground provides built-in histogram demos. Click the following links to try them out.

• Basic histogram

• Histogram with multi-dimension stacking and merging

  Important

  The data in the SLS Playground is for demonstration purposes only. Do not use this data in a production environment.

Configuration examples

General configurations

These settings apply to the entire histogram.

• Basic configurations

  Parameter	Description
  Title	The chart title.
  Display Title	Shows the chart title when enabled.
  Display Border	Shows a border around the chart when enabled.
  Display Background	Shows a background color for the chart when enabled.
  Display Time	Shows the query time in the chart when enabled.
  Fixed Time	Locks the query and analysis time range so that it is not affected by the dashboard's global time setting.

• Standard configurations

  Parameter	Description
  Format	The display format for numbers.
  Unit	The unit for numbers.
  Number of Digits after Decimal Point	The number of decimal places for numbers.
  Display Name	The display name for the field. This name overrides all other field names in the chart. To rename a specific field, use field configuration.
  Color Scheme	The color scheme for the chart. Built-in: Uses the built-in colors. Solid: Uses a single color. Threshold: Colors the chart based on configured thresholds.

• Histogram settings

  Parameter	Description
  Direction	The orientation of the histogram. Valid values: Vertical and Horizontal.
  Coordinate Scale	The x-axis interval. Applies only in non-Time Series Mode.
  Time Scale	The time scale. Applies only in Time Series Mode.
  Select Time Range	The time interval. Applies only in Time Series Mode.
  Buckets	The number of buckets. In non-Time Series Mode, if you set the Coordinate Scale, the number of buckets is not required.
  Rotation angle	The rotation angle of the text on the x-axis. This parameter is required when Direction is set to Vertical.
  Merge Columns	With multiple Y-axis fields, use the Merge Columns setting to configure how bars are stacked. No: Each bar starts from the bottom of the chart. Yes: Bars are merged into one. Stacked: Bars are stacked without overlapping.
  Line Width	The width of the bar borders.
  Transparency	The transparency of the histogram.
  Gradient Mode	The gradient mode of the histogram. Transparency: Applies a gradient based on the bar color and Transparency setting. No Gradient: Fills bars with a solid color.

• Query and analysis configurations

  Parameter	Description
  Axis X Field	The field for the x-axis. Default: automatically selected by SLS.
  Axis Y Field	The field for the y-axis. Specify multiple fields to generate a grouped histogram. Default: automatically selected by SLS.

• Legend configurations

  Parameter	Description
  Display Legend	Turn on the Display Legend switch to display the legend.
  Sorting Method	The display order of legend items in the chart. Valid values: No Sorting, Ascending, and Descending.
  Legend Position	The position of the legend.
  Actions	The behavior when you click a legend item. Single: Clicking a legend item shows only that item's data. Switch: Clicking a legend item toggles its visibility.
  Maximum width (height)%	The maximum width and height of the legend.

• Tooltip configurations

  Parameter	Description
  Sorting Method	The arrangement order of the data in the tooltip that appears when you hover over a bar. Valid values: No Sorting, Ascending, and Descending.
  Display Mode	The display mode of tooltip data. Applies when you hover over a bar.

• Axis x

  Parameter	Description
  Display Axis X	Turn on the Display Axis X switch to display the x-axis.
  Axis X Title	The title of the x-axis.
  Format	The time format for the x-axis. Applies only in Time Series Mode.
  Axis X Height	The height of the x-axis. Default: automatically set by SLS.
  Drag and Zoom	In Time Series Mode, after you drag to zoom in, you can refresh the global time or the time for the current chart.

• Axis y

  Parameter	Description
  Display Axis Y	Turn on the Display Axis Y switch to display the y-axis.
  Axis Y Title	The title of the y-axis.
  Axis Y Position	The position of the y-axis.
  Axis Y Width	The width of the y-axis. Default: automatically set by SLS.
  Maximum Value	The maximum value of the y-axis. Default: automatically set by SLS.
  Minimum Value	The minimum value of the y-axis. Default: automatically set by SLS.
  Elastic Maximum Value	The elastic maximum value of the y-axis. Takes effect only when all y-axis values are less than this value. Default: automatically set by SLS.
  Elastic Minimum Value	The elastic minimum value of the y-axis. Takes effect only when all y-axis values are greater than this value. Default: automatically set by SLS.
  Axis Y ID	The Y-axis ID. The value can be any string. In General Configurations, this field typically has no effect. To define multiple Y-axes, configure them in Field Configuration. Y-axes with different IDs display as separate axes. The Y-axis ID takes precedence over the unit configuration in Standard Configurations. Two Y-axes with the same unit are merged into one. Two Y-axes with the same unit but different IDs display separately.

• Variable substitution

  Parameter	Description
  Variable substitution	Variable substitution adds a variable-type filter to the chart. After configuration in General configurations, a filter appears in the upper-left corner of the chart. When you select a value, Simple Log Service replaces the variable in the query statement and reruns the analysis. Example 2: Set variable substitution.

• Documentation

  Parameter	Description
  Add Documentation Link	Adds a documentation link to the upper-right corner of the chart.

Field configuration

Field configurations apply custom visualization settings to a specific query result or data column. For parameter descriptions, see General configurations.

For example, you can customize the bar color for a specific y-axis field. A > GET indicates that you are configuring the GET field from query A. A > POST indicates that you are configuring the POST field from query A.

Interactions

Configure interaction occurrences for a query result or data column to enable drill-down analysis. Supported interactions include Open Logstore, Open Saved Search, Open Dashboard, Open Trace Analysis, Open Trace Details, and Create Custom HTTP URL. Add interaction occurrences to a dashboard for drill-down analysis.

For example, A > GET configures an interaction for the GET field from query A. If the interaction for the GET field is set to Open Logstore, clicking a GET value in the histogram and then clicking Open Logstore navigates to the specified Logstore.