Thanks for the review comments Todd. I shall fix the wording accordingly. Regards Ananth
> On 31 May 2017, at 5:50 am, Todd Lipcon <[email protected]> wrote: > > Hey Ananth, > > Thanks for posting this, and for working on the Kudu sink for Apex. > > One thing I wanted to note in the article: > > "Kudu output operator allows the client side timestamps to be propagated to > the Kudu server where the mutation is executed. This allows for out of > sequence data tuples to be ordered on the server side. The following snippet > of code in the upstream operator shows how this can be done." > > I think your understanding of the setPropagatedTimestamp() call is not quite > right. This timestamp propagation serves as a lower-bound for the assigned > timestamp at the server side, not as an exact setting of the server side > timestamp. Thus, if you perform two inserts, and the second insert has a > lower propagated timestamp, it does _not_ ensure that the first one takes > precedence. Since the Propagated Timestamp is a lower-bound, the second > insert will still be assigned a higher timestamp than the first. > > The purpose of this advanced API is to allow causal ordering to be maintained > between two writes. For example, imagine that client A writes data from > machine A, and then communicates with client B on machine B. Then, client B > performs a write. If we want to ensure that B's write is assigned a higher > timestamp than A, the setPropagatedTimestamp() API can ensure that (by > setting A's write's timestamp as the lower bound for B's write). But, it > can't be used to back-date a write as the article seems to be implying. > > Otherwise, the post is great! Thanks again for sharing your experience and > application. > > -Todd > >> On Tue, May 30, 2017 at 11:33 AM, Ananth G <[email protected]> wrote: >> Hello All, >> >> Apache apex now enables low latency high throughput writes to Kudu as a >> sink. More details on this on the atrato blog here: >> http://www.atrato.io/blog/2017/05/28/apex-kudu-output/ . Please use the >> comments section to provide any feedback. >> >> Regards, >> Ananth > > > > -- > Todd Lipcon > Software Engineer, Cloudera
