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Monitor Query Performance

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  • Considerations
  • Required Access
  • Enable and Disable Profiling
  • Access the Query Profiler

Only available on M10+ clusters and serverless instances

The Query Profiler diagnoses and monitors performance issues. This monitoring can expose slow-running queries and their key performance statistics in the Atlas UI. You can explore a sample of historical queries for up to the last 24 hours without additional cost or performance overhead.

Atlas collects and displays statistics from any of your mongod instances. The Query Profiler identifies slow queries based on log data from your mongod instances. Atlas displays this data in the Profiler section of an instance.


The Query Profiler differs from the Database Profiler. The Query Profiler identifies specific inefficient queries based on entries from your mongod logs. The Database Profiler returns detailed information about commands executed on the mongod based on the specified profiling level. Changing the profiling level doesn't impact the slow queries displayed in the Query Profiler.

The Profiler displays one aspect, such as Operation Execution Time or Server Execution Time (serverless instances), that could reveal slow database operations over a set time frame. It displays this data in both a chart and a table that each can filter on aspect and time frame.


You can use $comment to add descriptive information that will appear in the visual query profiler to the query predicate. This information makes it easier to analyze your profiler data.

Atlas manages the threshold for slow operations for each mongod host based on average operation execution time on that host. This threshold can be changed using the db.setProfilingLevel mongosh command.


Changing the threshold for slow operations using db.setProfilingLevel can impact performance and system log settings. Carefully consider any performance and security implications before you use db.setProfilingLevel to adjust profiler settings on a production deployment. Profiler settings reset to default values following a node restart.


To opt out of the Atlas-managed slow operation threshold and use a fixed slow query threshold of 100 milliseconds instead, use the Atlas Administration API. See Disable Managed Slow Operation Threshold. For M0, M2, M5 clusters and serverless instances, Atlas disables the Atlas-managed slow query operation threshold by default and you can't enable it.


Please read the following considerations before you enable profiling.

Profile data may include sensitive information including the content of database queries. Ensure that exposing this data to Atlas is consistent with your information security practices.

The Query Profiler displays up to 10,000 of the most recent operations, or 10MB of the most recent logs. Then, the Query Profiler won't display new operations for 24 hours.

Atlas displays no more than 10,000 data points in the Profiler charts.

Log data is processed in batches. Data can be delayed up to five minutes from realtime.

If a cluster experiences an activity spike and generates an extremely large quantity of log messages, Atlas may stop collecting and storing new logs for a period of time.


Log analysis rate limits apply only to the Performance Advisor UI, the Query Profiler UI, the Access Tracking UI, and the Atlas Search Query Analytics UI. Downloadable log files are always complete.

To enable or disable Performance Advisor and Profiler for a project, you must have the Project Owner role for the project or the Organization Owner role on its parent organization.

Atlas enables Profiling by default.

To disable profiling:

  1. Click Project Settings in the left navigation.

  2. Toggle Performance Advisor and Profiler to Off.

To access the Query Profiler:

  • For a cluster, click View Monitoring for that instance in the project panel then click Profiler.


    When you access the Query Profiler at the cluster level, the Query Profiler displays the data from the log on the primary node. You must select each specific secondary node to view any long-running queries on those nodes.

  • For a serverless instance, click the Monitoring tab.

Above the chart, select the metric and time period you want to see.

  1. Select the metric from the Display menu. Atlas accepts:

    • Default: Operation Execution Time or Server Execution Time (serverless instances)

    • Keys Examined

    • Docs Returned

    • Examined:Returned Ratio

    • Num Yields

    • Response Length

  2. Select the time period from the View Last menu. Atlas accepts:

    • 24 hr (default)

    • 12 hr

    • 6 hr

    • 1 hr

    • 15 min

To view a full query and its execution statistics, click on the point representing it on the chart.

Above the table, select the namespace, operation type, and metric you wish to profile:

  1. Click All Namespaces to change which combination of databases and collections to profile.

  2. Click All Operations to change which operations you want to profile.

  3. Click Operation Execution Time or Server Execution Time (serverless instances) to change which metric you want to profile. Atlas accepts:

    • Default: Operation Execution Time or Server Execution Time (serverless instances)

    • Keys Examined

    • Docs Returned

    • Examined:Returned Ratio

    • Num Yields

    • Response Length

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