4 ms·
Is this the kind of thing that makes Google's Spanner database possible?
by matt2000 9y ago
Is this the kind of thing that makes Google's Spanner database possible?
- 0xbear 9y agoOne of the things. They use GPS clocks as well.
- teraflop 9y agoYeah, even if you have atomic clocks in every datacenter, you need an external reference to synchronize them with each other. (If you try to calculate the offsets between two clocks by using something like NTP to measure round-trip times over the internet, you're implicitly assuming that packet delays in both directions are symmetrical.)
- sharpercoder 9y agoHow about syncing them at one physical place, moving while powered using a battery, then hot-deploy in target datacenter?
- nightfly 9y agoPretty sure relativity limits the usefulness of this. http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps....
- userbinator 9y agoIt's rather amazing that anyone with a couple of atomic clocks can see the effects of relativity themselves: http://leapsecond.com/great2005/ http://leapsecond.com/great2005/
- amelius 9y ago> Relativity is not just some abstract mathematical theory: understanding it is absolutely essential for our global navigation system to work properly! I wonder if we could get away by just building it and accounting for the error using some multiplier, without understanding the concept of relativity. I.e., how we would build it if we invented satellites before relativity.
- amelius 9y agoI wonder how well Google's database would work in an interplanetary setting, where due to high relative velocities the property of simultaneity does not exist.