Are DynamoDB conditional writes strongly consistent?

Question

Suppose that a given table already contains the following key value pair:

"abc" => { i: 1, v: "foo" }

Then, two clients issue conflicting concurrent conditional writes. Client 1 writes:

"abc" => { i: 2, v: "bar1" } if i == 1

Client 2 writes:

"abc" => { i: 2, v: "bar2" } if i == 1

Then, is it guaranteed that at most one client's write operation will succeed?

The answer is too short even for a comment: Yes. I mean, that is their whole point. — ruakh, Nov 29 '14 at 04:24
The answer may be short, but cheers from 2018. Sometimes the most concise answers are the best. — Kenny Worden, Jun 22 '18 at 04:15
If both requests come at the same time, how does DynamoDB determine which record it'll retain? `bar1` or `bar2`? — Joseph, Jan 03 '20 at 08:53
@dDarkLORD nope. But I assume whichever record makes it first to DDB — Joseph, May 14 '20 at 00:59

score 21 · Accepted Answer · answered Dec 01 '14 at 19:34

21

Yes, that's exactly the use case they're designed for. You can see an example in the docs.

answered Dec 01 '14 at 19:34

PherricOxide

1 Answers1