[chreniuc]

I'm curious about the latency between a backend app that runs on different cloud provider than aws(eg hetzner), because I've noticed that they run on aws(it shows up when choosing the region for your database). Has anyone used this and connected from a different cloud provider? Have you noticed big latencies?

[orware]

You will generally run into different types of latencies in this case since you have the general connection latency when those are getting established plus the regular physical/network latency between where the database is located and your own servers.

For connections, since a TLS handshake is required, the impact of physical distances can have a greater impact on the connection time. The following article: https://sking7.github.io/articles/44961356.html actually provides a good 3.5x-4x figure which correlates with some connection tests I've completed.

In other words, if an initial TCP packet takes ~100ms to get from the database to your server, then establishing a TLS connection to the database will probably be around 400ms.

Once the connection is established, running queries over an open connection is generally going to be quicker, at least for simpler queries. More complex queries will still take whatever time they need to process on the database end before they can start sending results back so results will generally vary there.

But going back to that 100ms example...if the amount of data being returned from a very simple query is minimal than the response time here would be very close to that 100ms figure over an already open connection and likely would go up from there depending on the complexity of the query and amount of data needing to be returned.

Since the connection hostnames are publicly accessible and TLS is always required for connections you can easily test from your own provider's location. So long as the general physical location isn't too far away from a supported region, the latency overall shouldn't be unusable.

I may have mangled some terminology/analogies above but hopefully that helps provide a bit of a ballpark for you. If you have specific to/from regions in mind I might be able to try and collect some specific numbers for you!

[toast0]

I haven't spent time optimizing TLS between a database client and server, but in HTTPS, using TLS 1.3 without early data (or TLS 1.2 with somewhat optimistic handshake handling) gets you to one added roundtrip, TLS 1.3 early data gets you down to zero added round trips. Early data isn't always appropriate, because there's potential for replays, but the latency improvement might be worth considering for some selects.

[minhazm]

It's depends on how far the two data centers are from one another. But the big cloud providers have data centers in similar locations since they usually want to be near an internet exchange[1]. For example most companies that provide cloud services have a data center in Virginia, USA. So if both data centers are in the same region then you can get numbers in the sub 5ms range. As long as you're not crossing the ocean the latency should be fine.

1. https://en.wikipedia.org/wiki/List_of_Internet_exchange_poin...