How to Measure Max Concurrent Application Devices Connected/Users

MongoDB Atlas App Services & Realm Atlas Device Sync
1

Hi all,

I’ve been looking into how to measure the maximum number of concurrent users connected to the app in Device Sync.

In Data Services, I can use this Connections chart, but this could include connection pooling between the application using Device Sync and the Database itself.

image

The above image looks like it’s measuring the second arrow between “Application” and “Database” :

User Device —> Application —> Database

I’d like to measure the maximum number of concurrent connections between “User Device” and “Application” in the first arrow.

When I go to the application itself, and then go to Metrics, then choose Sync in the drop down menu under View, I can see the current connections:

image

This looks like what I want, but not sure how to get this historically. I checked the atlas CLI and Admin API logs, but couldn’t quite find what I’m looking for. Most examples seem to reference the connections to the database itself.

Tried something like this, but can’t return data:

curl --user "${PUBLIC_KEY}:${PRIVATE_KEY}" \
  --digest \
  --header "Accept: application/vnd.atlas.2024-11-13+json" \
  -X GET "https://mongodb.prakticum-team.ru/proxy/cloud.mongodb.com/api/atlas/v2/groups/${GROUP_ID}/apps/${APP_ID}/sync/metrics?granularity=PT1M&period=PT1H&metrics=connections"

There is an option to download the logs as well that might work. I’m willing to do alot of heavy lifting to get the numbers if needed.

Thanks for any help or tips anyone might have.

2

Hi @stack_engineering,

You can use the admin API to fetch historical metrics - MongoDB Atlas App Services Admin API. The metric you’re looking for is ACTIVE_OPEN_SYNC_SESSIONS. Metric descriptions are outlined here for your reference: https://mongodb.prakticum-team.ru/docs/atlas/app-services/reference/metrics/#available-metrics.