Re:Spanner: Becoming a SQL System [pdf]
by tyingq on Monday May 15, 2017 @12:52AM
(#14339239)
The CockroachDB team did put up a blog post that talks about the tradeoffs.
The pertinent part was: "Spanner always waits on writes for a short interval, whereas CockroachDB sometimes waits on reads for a longer interval. How long is that interval? Well it depends on how clocks on CockroachDB nodes are being synchronized. Using NTP, itβs likely to be up to 250ms. Not great, but the kind of transaction that would restart for the full interval would have to read constantly updated values across many nodes. In practice, these kinds of use cases exist but are the exception."
The pertinent part was: "Spanner always waits on writes for a short interval, whereas CockroachDB sometimes waits on reads for a longer interval. How long is that interval? Well it depends on how clocks on CockroachDB nodes are being synchronized. Using NTP, itβs likely to be up to 250ms. Not great, but the kind of transaction that would restart for the full interval would have to read constantly updated values across many nodes. In practice, these kinds of use cases exist but are the exception."
https://www.cockroachlabs.com/blog/living-without-atomic-clo...