Applications Systems

Metric baselines

DPA collects a number of metrics from the databases and other infrastructure it monitors. To put these raw numbers in context of their historical performance, DPA computes baselines for each metric. Because the system load normally varies by time of day and day of week, these baselines should be computed separately for each time window. The user can choose which set of baselines to compute.

First published date

10/22/2018 10:31 AM

Last published date

10/22/2018 10:31 AM

Overview

This article discusses metric baselines shown in DPA.

Product section

Database Performance Analyzer

Resolution

Metrics baselines 

DPA collects a number of metrics from the databases and other infrastructure it monitors. To put these raw numbers in context of their historical performance, DPA computes baselines for each metric. Because the system load normally varies by time of day and day of week, these baselines should be computed separately for each time window. The user can choose which set of baselines to compute:

  1. One per hour of the day - all days of the week treated equally with 24 baselines per metric.
  2. One per hour of the day, weekdays only - data from Saturdays and Sundays are ignored when computing baselines with 24 baselines per metric.
  3. One per hour of the day per day of the week - each day of the week is considered separately with 168 baselines per metric.
  • Each baseline consists of the 10th percentile, the average, and the 90th percentile for the metric. Baselines are shown with lines and shading on metric charts.
  • Monitoring must be active for at least 1 day before a baseline can be calculated, and baselines become more visible as more monitoring days pass.
  • At this time, Baselines are not available for metrics collected for the VM Option.

 

Visibility

Baselines are currently visible in three places: 

  • Resources on Trends tab (drill down to one hour and switch to Timeslice tab).
    baselines3.PNG

  • Resources on Current tab (first page).
    baselines2.PNG

  • Resources tab (first page - any tab)
    baselines.PNG

Notes:

  • All these places are using the same cookie "showBaseline" for displaying or hiding baselines. If user sets VISIBLE (true value) on trends, it will also be visible on Current tab.
  • Default value is FALSE.
  • If cookie doesn't exists, baselines are hidden. Cookie serves only for display baselines and its buttons in the charts.

 

Options

  • Baselines and its buttons can be globally enabled/disabled by configuring METRICS_BASELINE_ENABLED in Options/Administration/Advanced Options/System Options (default value is enabled).
  • User can also enable/disable Baselines locally for specific instance by configuring METRICS_BASELINE_ENABLED in Options/Administration/Advanced Options/DB Instance Options.
  • METRICS_BASELINE_ENABLED settings in DB Instance Options overrides settings in System Option and both override cookie value.
  • TRUE means baseline buttons will be visible and baselines active.
  • FALSE means both baselines and baseline buttons will be hidden.

Example:

In DB Instance Options, if you set METRICS_BASELINE_ENABLED = true but in System Options you set METRICS_BASELINE_ENABLED = false,this will make it visible for a specific instance and will make it hidden for every other instance if the cookie is also set to true. User will see baselines in graphs but only in this specific instance.

 

Functionality

  • Functionality on Trend and Current tabs are the same. After clicking on Show Baseline, it displays normal range and average baselines in graphs. 
  • On Resources tab, it displays both baselines for time periods for a week or less with average baseline.
  • On the Last Hour chart, hovering on the baseline will present the baseline data for both hours spanned within the last hour period.
  • Data for calculating baselines is aggregated into 24 slots accounting for every hour in a day. When presenting charts spanning more than one day (last 24 hours, 1 week), the baselines for each day are based upon the same 24 slots. This effectively prevents baseline computations from including data from days of the current view into the rendered one. 

 

Configuration Parameters

The following are parameters for the baselines feature. These are found under options > Administration tab > Advanced options. 

 

Note: The same parameters are available for specific instances in Advanced Options/DB Instance Options. 

 

PARAMETER NAMELOCATIONVALUESDESCRIPTIONSUPPORT OPTION
METRICS_BASELINE_ENABLED Advanced Options/System Options
  • TRUE (default)
  • FALSE
  • TRUE = Baselines are enabled and its buttons are visible for all instances
  • FALSE = Both Baselines and its buttons are hidden for all instances
Yes
METRICS_BASELINE_TYPICAL_HOUR_CALCULATIONAdvanced Options/System Options
  • All days of the Week
  • Weekdays Only (default)
  • Same Day of Week
The baseline calculation on Resource Metric charts compares a given hour (e.g. 2pm-3pm) to the same hour on prior days.
This option determines which days of the week are included for prior days. 		NO 
METRICS_BASELINE_PERCENTILEAdvanced Options/System Options
  • 80 (default)
Enable Baseline feature, if this is false then the button to toggle baseline on and off will not display and baselines will not show. Percentile to use in typical hour calculations for Baseline feature Yes
 

baselines_parameters.PNG