Per the Server Support Matrix https://www.mongodb.com/try/download/ops-manager support for CentOS Stream 8 is not al.
We would like to see the currently supported MongoDB OPS Manager version 5.x available on the CentOS Stream 8 distribution.

Add Change streams and Trigger capabilities to Time Series Collections.
Current Limitations don't allow this.
https://docs.mongodb.com/manual/core/timeseries/timeseries-limitations/#change-streams

im looking at one of my queries that a system regularly runs and some times we look for records that are within up to 250 different centerspheres, i wornder if we could enable, like geowithin has the ability to support multiple poligons, we could enable multiple centerspheres ,


$match: {{'location':{
"$geoWithin" : {
"$centerSphere" : [[ 14.4321, -9.4321], 2.5232135647961246e-05]
}
}}, {'location':{
"$geoWithin" : {
"$centerSphere" : [[ 14.4321, -9.4321], 2.5232135647961246e-05]
}
}}, ...}


we could do :
```
$match: {'location':{
"$geoWithin" : {
"$centerSpheres" : [
[[ 14.4321, -9.4321], 2.5232135647961246e-05] ,
[[ 14.4321, -9.4321], 2.5232135647961246e-05],
...
]

    } 
}}

There is a specific collection that I need more performance than others. Is there a way to assign more ram/memory to a specific collection?

As high throughput clusters grow and documents become larger, the MongoDB balancer may begin impacting workloads.

I'd like the ability to throttle the speed at which the balancer or chunk migrator runs such that impact is minimised.

database in restricted mode can very helpful .. so we can carry out , lock users out, rebuild indexes, compact and other admin tasks.

Currently time series collections have a single TTL across all inherent granularities. It would be great to specify a TTL for each granularity. For example:

For seconds: 1 week
For hours: 1 month
Others: never

Course information should be held longer than finer information in some cases - currently they all fall under the main TTL specified.

Please provide a $populate stage that allows to resolve single referenced documents.
Internally it could use the combination of $lookup and $unwind:

https://stackoverflow.com/questions/41482559/how-to-return-single-object-instead-of-array-in-lookup-of-mongodb

Related:

https://stackoverflow.com/questions/37793844/mongodb-how-to-resolve-dbref-on-client-side

https://jira.mongodb.org/browse/SERVER-22497

Paging is a common functionality for REST APIs. When implementing paging queries for large datasets skip and limit is often not an option. When using query filters with non unique fields, such as creation date there can be problems such as duplicate entities on subsequent pages. It would be great to be able to additionaly pass in an offset document reference, that would be used as a start in case the filter does not lead to a unique starting point.

so for example
db.test.find({"creationDate" : {$gte:ISODate('2021-08-27T07:25:00Z')}, {"offset":<ObjectId>).sort({"creationDate":1}).limit(20)

When the max number of connections is reached, no one can login to the database until some connections are closed or a failover is triggered (killing all the connections).

The admin users should have a few reserved connections so that they can login to the database and take actions, like kill some connections.

There is the $avg operator that returns the average of a set of values. Why not a $median?

We are in the process of implementing AWS SSO across our Organisation and wanted to tie this in with mongodb-aws for database authentication.
Unfortunately we have been informed the 2 services are not compatible.

This would be a really useful add on to improve management of our systems.

As a DBA I'd like to identify unused collections so that I can remove them to optimize performance.
As of now there doesn’t seem to be a direct way. One option could be to settup auditing or using logging (e.g. set the slow op timer to 0 so we log everything).
An other might be to use the collstats command and frequently traverse all collections..

I'd be happy to get a direct method to show me unused resp. last usage of a collection. Based on DB level or even over all DBs.

Per the MongoDB Server Supported Platforms Matrix support for Ubuntu 21.04 is not yet available.
We would like to see the currently supported MongoDB Server versions available on the Ubuntu 21.04 LTS distribution which was released on 22 April 2021

This is along the lines of a flashback, to a previous point in time say from a very impacting change to data.. A large delete or data modification event. This avoids the need to take a complete outage for hours and hours restoring TBs of data and re-applying change logs. Would be great if this could be done to the granularity of a single or multiple collections too. This could use the oplogs present locally or in the oplog store.

It's not always obvious which aggregation stages are blocking or non-blocking when viewing explain output for an aggregation command. It would be helpful to include a blocking flag for each stage of an aggregate command in its explain output.