[spmurrayzzz]

Thanks for engaging here, and congrats on the round!

I've reviewed all these resources multiple times in the past, which is what prompted me to do my own benchmarks (in which mongo outperforms both multinode and single node configurations).

Some issues I noticed:

- youre using gopkg.in/mgo.v2 which is a mongo driver that hasn't had a release in 6 years. Not sure of the general performance impact here, but my tests use mongo 4.2 with a modern node.js driver. So thats one difference.

- your indexing strategy for mongo is easily changed to be able to get much better performance than the naive compound approach you took in the code (measurement > tags.hostname > timestamp).

- you didnt test the horizontal scaling path at all, this is where mongo arguably shines

I'm glad you all open source this stuff because it helps engineering leaders make better decisions, so thank you for that. But your data does not align with my own: either our production metrics or through structured load testing.

[mfreed]

Thanks for the concrete feedback/suggestions!