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 >>> >>> >>> >>> >>> >> >> >
