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josephglast Saturday at 11:12 PM2 repliesview on HN

Consistent ordering of concurrent operations is easy though. Just detect this case (via logical clocks) then order using node ids or transaction ids if the logical clocks show the transactions as being concurrent. Am I missing something? This feels like a very solved problem. (I’ve worked on CRDTs where we have the same problem. There exist incredibly fast algorithms for this.)


Replies

lll-o-lllyesterday at 1:28 AM

> Am I missing something?

I don’t think so, I think it is solved in the general sense. However what Spanner does is unique, and it does use synchronised clocks in order to do it.

However, Spanner does not solve the inter-continental acid database with high write throughput. So I don’t see it as ground breaking. CRDT’s are interesting, I’ve followed your work for a long time, but too constrained to solve this general problem I think.

georgelyonyesterday at 1:34 AM

Yes, though the API of having a write-only value that is a monotonically increasing counter is much simpler than having to think about causality or logical clocks.