Re:Show HN: FaunaDB, a strongly consistent, globally distrib...
by felixgallo on Wednesday March 15, 2017 @07:42PM
(#13881000)
snapshot time as in wall clock time? What is the time source?
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Re:Show HN: FaunaDB, a strongly consistent, globally distrib...
by freels on Wednesday March 15, 2017 @08:01PM
(#13881110)
It's variable, and the client can provide it. By default, we use the greater of wall clock time or the highest timestamp transaction timestamp the node serving the query has seen.
Re:Show HN: FaunaDB, a strongly consistent, globally distrib...
by felixgallo on Wednesday March 15, 2017 @08:07PM
(#13881143)
In that case, your database loses data and is definitely not strongly consistent. Why do you claim it is?
Re:Show HN: FaunaDB, a strongly consistent, globally distrib...
by freels on Wednesday March 15, 2017 @08:23PM
(#13881240)
To be clear, read-write transactions are applied in a consistent order derived from the transaction log. Read-only transactions can rely on the fact that read-write transactions are totally ordered, and execute without global coordination while still providing a guarantee of serializability. Wall clock time is used as a suggestion only, in order for the database's logical timestamps to track as close to real time as possible.
We will have more information about how Fauna meets its consistency guarantees in a future blog post.
Re:Show HN: FaunaDB, a strongly consistent, globally distrib...
by felixgallo on Wednesday March 15, 2017 @09:58PM
(#13881745)
you can't have a read transaction that's serializable that doesn't go through global coordination unless all of the data is guaranteed to only ever be local. Looking forward to the blog post.
Re:Show HN: FaunaDB, a strongly consistent, globally distrib...
by anentropic on Thursday March 16, 2017 @09:31AM
(#13884813)
looking forward to Jepsen...