Monitor Query Performance
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.
Note
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.
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.
Note
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.
Note
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.
Considerations
Important
Please read the following considerations before you enable profiling.
Security
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.
Data Analysis Limitations
The Query Profiler displays up to the first of the following limits:
the most recent 10,000 operations, or
the most recent 10MB of logs.
Data Display Limitations
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.
Log Quantity
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.
Note
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.
Enable and Disable Profiling
Important
Required Privileges
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:
Click Project Settings in the left navigation.
Toggle Performance Advisor and Profiler to Off.
Access the Query Profiler
To access the Query Profiler:
For a cluster, click View Monitoring for that instance in the project panel then click Profiler.
For a serverless instance, click the Monitoring tab.
Profiling Chart
Above the chart, select the metric and time period you want to see.
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
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.
Profiling Table
Above the table, select the namespace, operation type, and metric you wish to profile:
Click All Namespaces to change which combination of databases and collections to profile.
Click All Operations to change which operations you want to profile.
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