3 ms·
It's more like what CockroachDB or TiDB use underneath. They all are suited for local clusters, but cannot perform well enough replicating across multiple far a
by zzzcpan 9y ago
It's more like what CockroachDB or TiDB use underneath. They all are suited for local clusters, but cannot perform well enough replicating across multiple far away datacenters over public internet, latency trade offs would be unbearable. Spanner is a bit different, with Google's fancy clocks and fancy networks, it can get better latency trade offs that might satisfy more applications.
Citus I can't remember, but if Citus does it properly wrt consistency, it should be in the same category as CockroachDB and TiDB, there is no magic.
- kuschku 9y agoCockroachDB (and I assume TiDB as well) can have the same properties and same awesome latencies as Spanner, if you have the same hardware. So if you actually put down your own fiber, and install GPS clocks in each rack, you’ll be able to enjoy the same results.
- polskibus 9y agoDoes CockroachDB use TrueTime or a similar technique?
- wll 9y agoSee CockroachDB’s Living Without Atomic Clocks [0]. TrueTime [1] is a proprietary Google technology. Considering TrueTime upper bound uncertainty (< 10ms) [2], it may depend on Google’s network quality and breadth. [0] https://www.cockroachlabs.com/blog/living-without-atomic-clocks/ https://www.cockroachlabs.com/blog/living-without-atomic-clo... [1] https://cloud.google.com/spanner/docs/true-time-external-consistency https://cloud.google.com/spanner/docs/true-time-external-con... [2] https://static.googleusercontent.com/media/research.google.com/en//archive/spanner-osdi2012.pdf https://static.googleusercontent.com/media/research.google.c...
- AlphaSite 9y agoDo they do something like: http://fireless.cs.cornell.edu/publications/dtp_sigcomm16.pdf http://fireless.cs.cornell.edu/publications/dtp_sigcomm16.pd... ?
- kuschku 9y agoCockroachDB assumes you use NTP on your servers — but if you actually put GPS clocks into your servers, you could adjust the safety interval it assumes for clock drift down, and it'd behave pretty much the same as Google's.