[_benedict]

> If the committed state in the database records the transactions in a different order than an external observer could have observed them

So, property (1) provides this for non-overlapping commutative transactions. If w1 writes c1, then finishes; w2 writes c2 then finishes; then if r1,r2,r3, etc don't overlap either w1 or w2 either, then they must correctly witness their execution order and be "externally consistent".

If transaction executions overlap, we must work harder to ensure we see each others' strict serializable order, and so we simply avoid ordering ourselves with transactions that cannot affect our outcome. If these other transactions cannot affect our outcome, then we can't witness anything externally about them, by definition.

[evancordell]

That makes more sense, thank you for the explanation.

Are there any plans for accord to permit snapshot queries?

[_benedict]

Yes, amongst other things. It's certainly doable, and I expect they will arrive at some point, but I cannot say with any confidence when that might be.