I guess it's technically possible but then we'll need to update the binary
protocol. Just create a JIRA and ask for this feature

On Tue, May 10, 2016 at 5:00 AM, Lu, Boying <boying...@emc.com> wrote:

> Thanks very much.
>
>
>
> I understand that the data needs to be read from the DB to get the next
> ‘PagingState’.
>
>
>
> But is it possible not to return those data to the client side, just
> returning the ‘PagingState’?
>
> I.e. the data is read on the server side, but not return to client side,
> this can save some bandwidth
>
> between client and server.
>
>
>
>
>
> *From:* DuyHai Doan [mailto:doanduy...@gmail.com]
> *Sent:* 2016年5月9日 21:06
> *To:* user@cassandra.apache.org
> *Subject:* Re: A question to 'paging' support in DataStax java driver
>
>
>
> In a truly consistent world (should I say "snapshot isolation" world
> instead), re-reading the same page should yield the same results no matter
> how many new inserts have occurred since the last page read.
>
>
>
> Caching previous page at app level can be a solution but not viable if the
> amount of data is huge, also you'll need a cache layer and deal with cache
> invalidation etc ...
>
>
>
> The point is, providing snapshot isolation in a distributed system is hard
> without some sort of synchronous coordination e.g. global lock (read
> http://www.bailis.org/papers/hat-vldb2014.pdf)
>
>
>
>
>
> On Mon, May 9, 2016 at 2:17 PM, Bhuvan Rawal <bhu1ra...@gmail.com> wrote:
>
> Hi Doan,
>
>
>
> What does it have to do being eventual consistency? Lets assume a scenario
> with complete consistency and we are at page X, and at the same time some
> inserts/updates happened at page X-2 and we jumped to that.
>
> User will see inconsistent page in that case as well, right? Also in such
> cases how would you design a user facing application (Cache previous pages
> at app level?)
>
>
>
> Regards,
>
> Bhuvan
>
>
>
> On Mon, May 9, 2016 at 4:18 PM, DuyHai Doan <doanduy...@gmail.com> wrote:
>
> "Is it possible to just return PagingState object without returning
> data?" --> No
>
>
>
> Simply because before reading the actual data for each page of N rows, you
> cannot know at which token value a page of data starts...
>
>
>
> And it is worst than that, with paging you don't have any isolation. Let's
> suppose you keep in your application/web front-end the paging states for
> page 1, 2 and 3. Since there are concurrent inserts on the cluster at the
> same time, when you re-use the paging state 2 for example, you may not get
> the same results as the previous read.
>
>
>
> And it is inevitable in an eventual consistent distributed DB world
>
>
>
> On Mon, May 9, 2016 at 12:25 PM, Lu, Boying <boying...@emc.com> wrote:
>
> dHi, All,
>
>
>
> We are considering to use DataStax java driver in our codes. One important
> feature provided by the driver we want to use is ‘paging’.
>
> But according to the
> https://datastax.github.io/java-driver/3.0.0/manual/paging/, it seems
> that we can’t jump between pages.
>
>
>
> Is it possible to just return PagingState object without returning data?
> e.g.  If I want to jump to the page 5 from the page 1,
>
> I need to go through each page from page 1 to page 5,  Is it possible to
> just return the PagingState object of page 1, 2, 3 and 4 without
>
> actual data of each page? This can save some bandwidth at least.
>
>
>
> Thanks in advance.
>
>
>
> Boying
>
>
>
>
>
>
>
>
>
>
>

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