2 ms·

Well, if you want ACID then you are going to have to pay for at least one geographic round trip per committed transaction. (So why not go active/passive, and h

Well, if you want ACID then you are going to have to pay for at least one geographic round trip per committed transaction. (So why not go active/passive, and have at least one of your datacenters be fast?) But what if you have different pieces of data and you want them to be fast in different datacenters? I think a great solution to this can be layered on top of multiple FoundationDB clusters, each using the satellite mode, but this is one thing that I at least haven't been able to think of a way to provide properly at the data model agnostic key/value store layer - the details about what to put where seem fundamentally dependent on your data model.

wll 8y ago
> So why not go active/passive, and have at least one of your datacenters be fast? While local writes would stay fast, wouldn’t active/passive see higher-latency non-local writes than Spanner or Fauna’s (assuming a NAM-EUR-ASIA topology)? I agree with and do appreciate the multiple FoundationDB clusters suggestion.
- voidmain 8y ago
  I'm speculating, but I think in this mode, from the "slow" datacenters you would see one round trip time to start a transaction, then reads will be fast (they can be done safely from your local datacenter because of MVCC), and then one round trip time to commit the transaction. I think that's as good as Spanner does with the same geography, but I'm not sure. I think you could get rid of the first round trip time even without any clock synchronization nonsense, by speculating on a read version for read/write transactions. And 1xRTT is obviously as fast as physically possible for ACID.
  - voidmain 8y ago
    Update: Apparently Spanner is way slower than I thought in "slow" datacenters, doing a round trip for every transactional read. So this would absolutely stomp that. (Although spanner, as a higher level system, has the ability to move different data to be fast in different regions built in, which is nice, and as I said it will probably have to be a layer feature in the fdb world)

wll 8y ago

> So why not go active/passive, and have at least one of your datacenters be fast? While local writes would stay fast, wouldn’t active/passive see higher-latency non-local writes than Spanner or Fauna’s (assuming a NAM-EUR-ASIA topology)? I agree with and do appreciate the multiple FoundationDB clusters suggestion.

voidmain 8y ago
I'm speculating, but I think in this mode, from the "slow" datacenters you would see one round trip time to start a transaction, then reads will be fast (they can be done safely from your local datacenter because of MVCC), and then one round trip time to commit the transaction. I think that's as good as Spanner does with the same geography, but I'm not sure. I think you could get rid of the first round trip time even without any clock synchronization nonsense, by speculating on a read version for read/write transactions. And 1xRTT is obviously as fast as physically possible for ACID.
- voidmain 8y ago
  Update: Apparently Spanner is way slower than I thought in "slow" datacenters, doing a round trip for every transactional read. So this would absolutely stomp that. (Although spanner, as a higher level system, has the ability to move different data to be fast in different regions built in, which is nice, and as I said it will probably have to be a layer feature in the fdb world)