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Simple Log Service:Histogram

Last Updated:Nov 26, 2024

You can use a histogram to visualize the distribution of continuous data and the frequency distribution of data. This helps you understand data features in an efficient manner. This topic describes how to configure a histogram. This topic also provides examples of histograms.

Overview

A histogram consists of vertical stripes or line segments that have different heights to show the distribution of data. The vertical stripes or line segments in a histogram are plotted based on the frequency, quantity, or other statistics of data, and are arranged along the x-axis. Compared with column charts, histograms are more statistically significant. The following list describes the differences between histograms and column charts:

  • A histogram displays the distribution of data. A column chart displays the differences between various categories of data.

  • The x-axis in a histogram displays numeric data, such as length, weight, and time values. The x-axis in a column chart displays categorical data, such as request methods.

  • In a histogram, bars typically have little or no gap because the data is continuous. In contrast, a column chart has spacing between bars of different categories to highlight their distinctions.

For more information about the entry point to add a histogram, see Add a chart to a dashboard.

Configuration example

Basic histogram

  1. Log on to the Simple Log Service console. In the Projects section, click the project you want.

  2. In the left-side navigation pane, choose Dashboard > Dashboards. In the dashboard list, click the dashboard you want. In the upper-right corner of the dashboard page, click Edit. In edit mode, click Add > Add Chart.

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  3. On the right side of the Edit Chart page, select Histogram in the Chart Types section and configure parameters in the Query and Analysis Configurations section based on the following figure. On the left side of the Edit Chart page, configure the query time range, Logstore, and query statement for the histogram. After you complete the configuration, click Apply in the upper part of the Edit Chart page to view the configuration effects of the histogram.

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    If you want to use the x-axis to represent time, we recommend that you turn on Time Series Mode in the upper part of the Edit Chart page. For more information, see Time series mode. If you turn on Time Series Mode, Simple Log Service automatically transforms raw data to time-formatted data and displays the distribution of data from the time dimension. The following query statement is used to query the number of records at 30-minute intervals:

    * | select __time__ - __time__ % 1800 as t, COUNT(*) as c group by t order by t asc limit 10000

Multi-dimension stacking

  1. Log on to the Simple Log Service console. In the Projects section, click the project you want.

  2. In the left-side navigation pane, choose Dashboard > Dashboards. In the dashboard list, click the dashboard you want. In the upper-right corner of the dashboard page, click Edit. In edit mode, click Add > Add Chart.

    image

  3. On the right side of the Edit Chart page, configure parameters in the Histogram Settings and Query and Analysis Configurations sections based on the following figure. On the left side of the Edit Chart page, configure the query time range, Logstore, and query statement for the histogram. After you complete the configuration, click Apply in the upper part of the Edit Chart page to view the configuration effects of the histogram.

    image

    The following query statement is used to query the numbers of GET and POST requests per minute:

    * | select __time__ - __time__ % 60 as t, count_if(request_method = 'GET') as GET, count_if(request_method = 'POST') as POST group by t order by t asc limit 1000

Configuration on the General Configurations tab

You can configure global settings for a histogram on the General Configurations tab.

  • Basic Configurations

    Parameter

    Description

    Title

    The title of the chart.

    Display Title

    If you turn on Display Title, the title of the chart is displayed.

    Display Border

    If you turn on Display Border, the borders of the chart are displayed.

    Display Background

    If you turn on Display Background, the background color of the chart is displayed.

    Display Time

    If you turn on Display Time, the query time range of the chart is displayed.

    Fixed Time

    If you turn on Fixed Time, the query time range of the chart is independent of the global time range of the dashboard.

  • Standard Configurations

    Parameter

    Description

    Format

    The display format of numeric values.

    Unit

    The unit of numeric values.

    Number of Digits after Decimal Point

    The decimal places of numeric values.

    Display Name

    The name of the display field.

    If you specify a value for Display Name, the value is used as the names for all display fields in the chart. If you want to change the name of a display field, you must configure parameters on the Field Configuration tab.

    Color Scheme

    The color scheme of the chart.

    • Built-in: uses the built-in color scheme.

    • Solid: uses the color that you select.

    • Threshold: uses different colors for different values based on the specified thresholds for the values.

  • Parameters in the Histogram Settings section

    Parameter

    Description

    Direction

    The direction of the histogram. Valid values: Vertical and Horizontal.

    Coordinate Scale

    The interval between values on the x-axis. This parameter is available only if you turn off Time Series Mode.

    Time Scale

    The time scale. This parameter is available only if you turn on Time Series Mode.

    Select Time Range

    The interval between values on the x-axis. This parameter is available only if you turn on Time Series Mode.

    Buckets

    The number of buckets.

    If you turn off Time Series Mode and configure the Coordinate Scale parameter, you do not need to configure this parameter.

    Rotation Angle

    The direction of the text on the x-axis.

    If you set the Direction parameter to Vertical, you must configure this parameter.

    Merge Columns

    If you specify multiple fields for the y-axis, you can configure the Merge Columns to specify the manner in which the columns are displayed. Valid values:

    • No: The value of each field is counted from the bottom of each column.

    • Yes: The values of fields are merged into one column.

    • Stacked: The columns of different categories are stacked and do not overlap with each other.

    Line Width

    The width of the border.

    Transparency

    The transparency of the histogram.

    Gradient Mode

    The gradient mode of the histogram. Valid values:

    • Transparency: If you select this mode, the histogram has a color gradient that is affected by the column color and the value of the Transparency parameter.

    • No Gradient: If you select this mode, the histogram does not have a color gradient. The column color is used in the histogram.

  • Parameters in the Query and Analysis Configurations section

    Parameter

    Description

    Axis X Field

    Select a field as the x-axis.

    By default, Simple Log Service automatically selects an appropriate field as the x-axis.

    Axis Y Field

    Select a field as the y-axis. You can specify multiple fields to generate a grouped histogram.

    By default, Simple Log Service automatically selects an appropriate field as the y-axis.

  • Parameters in the Legend Configurations section

    Parameter

    Description

    Display Legend

    If you turn on Display Legend, the legend is displayed in the histogram.

    Sorting Order

    The order in which the legend items are sorted.

    Legend Position

    The position of the legend in the histogram.

    Actions

    The data display effect when you click a legend item. Valid values:

    • Single: If you click a legend item, only the data for the legend item is displayed in the histogram.

    • Switch: If you click a legend item, the data for the legend item is hidden or displayed in the histogram.

    Maximum Width (Height)%

    The maximum width and height of the legend.

  • Parameters in the Tooltip Configurations section

    Parameter

    Description

    Sorting Order

    The sorting method of data.

    When you move the pointer over a column whose data you want to view, the data is displayed based on the sorting method that you specify.

    Display Mode

    The display mode of data.

    When you move the pointer over a column whose data you want to view, the data is displayed based on the display mode that you specify.

  • Parameters in the Axis X section

    Parameter

    Description

    Display Axis X

    If you turn on Display Axis X, the x-axis of the histogram is displayed.

    Axis X Title

    The title of the x-axis.

    Format

    The format of the time on the x-axis. This parameter is available only if you turn on Time Series Mode.

    Axis X Height

    The height of the x-axis.

    By default, Simple Log Service automatically specifies the height of the x-axis.

    Drag and Zoom

    Specifies whether to refresh the global time or the current single chart time after you drag and zoom specific columns if you turn on Time Series Mode.

  • Parameters in the Axis Y section

    Parameter

    Description

    Display Axis Y

    If you turn on Display Axis Y, the y-axis of the histogram is displayed.

    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.

    By default, Simple Log Service automatically specifies the width of the y-axis.

    Maximum Value

    The maximum value of the y-axis.

    By default, Simple Log Service automatically specifies the maximum value of the y-axis.

    Minimum Value

    The minimum value of the y-axis.

    By default, Simple Log Service automatically specifies the minimum value of the y-axis.

    Elastic Maximum Value

    The elastic maximum value of the y-axis. The elastic maximum value takes effect only when all values of the y-axis are less than the elastic maximum value.

    By default, Simple Log Service automatically specifies the elastic maximum value of the y-axis.

    Elastic Minimum Value

    The elastic minimum value of the y-axis. The elastic minimum value takes effect only when all values of the y-axis are greater than the elastic minimum value.

    By default, Simple Log Service automatically specifies the elastic minimum value of the y-axis.

    Axis Y ID

    The ID of the y-axis. If you configure only one y-axis on the General Configurations tab, this parameter does not take effect. If you want to configure multiple y-axes, you must configure the required parameters on the Field Configuration tab. The ID of the y-axis is a string. A y-axis that has a specified ID represents a unique y-axis in a histogram.

    The specified ID for the y-axis takes precedence over the unit that you specify in the Standard Configurations section. For example, if two y-axes have the same unit, they are merged into one y-axis. If two y-axes have the same unit but different IDs, they are displayed as two y-axes.

  • Parameters in the Variable Replacement section

    Parameter

    Description

    Variable Replacement

    The settings for variable replacement. You can click AddVariable Replacement to add a filter of the Variable Replacement type to the table. After you configure the settings for variable replacement on the General Configurations tab, Simple Log Service adds a filter in the upper-left corner of the table. You can select a value from the filter drop-down list. Then, Simple Log Service automatically replaces the variable in the query statement of the table with the variable value indicated by the value that you select, and performs a query and analysis operation. For more information, see Example 2: Configure variable replacement.

  • Parameters in the Documentation section

    Parameter

    Description

    Add Documentation Link

    The button that allows you to specify custom document links and descriptions. After you configure the settings, the specified information is displayed in the upper right corner of the histogram.

Configuration on the Field Configuration tab

You can configure personalized display settings for the results of a single query statement or for a single column of data in the results. For more information, see Configuration on the General Configurations tab.

If you want to specify a color for the columns of a field on the y-axis, you can configure the field on the Field Configuration tab. For example, you can select A > GET to configure settings for the GET field in the results of Query Statement A. You can also select A > POST to configure settings for the POST field in the results of Query Statement A.

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Configuration on the Interaction Occurrences tab

You can configure an interaction occurrence for the results of a single query statement or for a single column of data in the results to analyze data in a finer-grained manner. Supported types of interaction occurrences include Open Logstore, Open Saved Search, Open Dashboard, Open Trace Analysis, Open Trace Details, and Create Custom HTTP URL. For more information, see Interaction occurrences.

For example, you can select A > GET to configure an Open Logstore interaction occurrence for the GET field in the results of Query Statement A. After you configure the interaction occurrence, you can click the value of the GET field in the histogram and click Open Logstore in the popover that appears. Then, you are navigated to the Logstore that you specify.

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