[winrid]

Again this microbenchark is useless. Don't pick databases this way. This is not the kind of operation you should be worrying about optimizing, it's not usually the bottleneck or what is slow.

Setup a clone of prod and build a tool to replay your traffic to it.

I have lots of data from datadog and ops manager but not going to take the time to publish ATM.

I just moved a 4tb deployment from 3.2 to 7. It cut max query time by about half. I actually went to instances with half the cpus, too (although I switched from ebs to ssds).

[hartator]

> Again this microbenchark is useless. Don't pick databases this way. This is not the kind of operation you should be worrying about optimizing, it's not usually the bottleneck or what is slow

It was for us. API calls that need to aggregate stats on same ID. We found a way around, but it would not have been an issue if MongoDB 8 was like 2x faster.

> I just moved a 4tb deployment from 3.2 to 7. It cut max query time by about half. I actually went to instances with half the cpus, too (although I switched from ebs to ssds).

Just single-core performance improvement in the last 10-year might explain your outperformance.

[winrid]

> Just single-core performance improvement in the last 10-year might explain your outperformance.

Nope, after migration max query time was still over a minute in some cases. What makes the biggest difference is performance tuning. After a week or so of index tuning, I got max index time below 6s. If Mongo makes each query take 2ms instead of 1ms, it literally doesn't matter to that customer or their customers, since it's just noise at that point. The old instances were M5s, so not that old.

The point is that the few nanoseconds difference you're measuring is not what you spend the most time on, usually.

Also you mentioned write performance. If you set journal commit interval to 500ms or something, then you can easily beat the old 3.2 write speeds, since if you're using 3.2 you probably don't care that much about journal commit intervals anyway ^_^