MongoDB, add "pages written from cache"

[GeeBee93]

Feature Request

Proposal:

Currently the mongodb input supports already a lot of different statistics about the performance of an instance. However, the attribute "pages written from cache" is not implemented. Even mongodb says in their documentation (see: https://docs.mongodb.com/manual/reference/command/serverStatus/#serverstatus.wiredTiger.cache.pages-written-from-cache): Number of pages written from the cache. wiredTiger.cache.pages written from cache with the wiredTiger.cache.pages read into cache can provide an overview of the I/O activity.

Current behavior:

"wiredTiger.cache.pages written from cache" is not gathered at all.

Desired behavior:

"wiredTiger.cache.pages written from cache" would be available for further database performance analysis.

Use case:

As already stated in the documentation it would be great to have that attribute to get a better overview of I/O activity of a mongodb instance.

Thank you! :-)

[GeeBee93]

If somebody is interested, I forked telegraf and implemented the feature: GeeBee93@db1b20b

I would like to create a PR, but I am in the final steps of my master theses and really busy. However, just feel free and use my repo.

Awesome work telegraf - thank you so much!

[vikkyomkar]

I will look into this issue

[reimda]

Looks like #7870 added this but didn't automatically close it.