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by ignoramous 2664 days ago
Great work. Building a distributed database isn't easy at all and takes considerable effort. I'd like to see more on failure scenarios. Here's a few preliminary questions I have (admittedly, I haven't read the entire post, apologies if my queries are answered already):

What is the SLA for durability and availability of the db?

- how are scenarios like edge locations going down for multiple minutes handled? Are the writes lost?

- how many replicas of data at a single edge location?

- Are there limits on the table size (how does one enforce this in a multi-master mode)?

- what's the SLA on replication time to say, at least 50% edge locations, and then to 100%?

Are DDL operations allowed? If so, how are the conflicts handled?

If data is stored in LSMs underneath, how are geo location queries handled? Is there an index/materialised view? If so, how long does that take to generate?

What's the TPS/QPS supported for the KV interface?

- Is there a scenario where a set of operations at X TPS across edge locations might then take a long time to converge globally?

It'd be great if you can list down scenarios where the db can lose write to 'true conflicts' in a FAQ somewhere.

- For instance, what happens in a create-delete-create scenario where a table is created at one edge location, deleted at another, created at a third edge location; all the while when there's writes and reads happening globally?

Thanks.

2 comments

Thanks for the truly thoughtful questions - I will put together a short faq and post a link and a a tl/dr answer here.

We also have a more technical internals paper almost completed and will publish next week.

Thanks again! This is such a helpful comment.

Hi Ignoramous - Thanks. Very helpful comment with good questions. I will update or cover in the next post.

Regards