Thanks Kurt, I thought about that but one issue is that we are doing limit/offset not pages. So one customer can choose to page through the list in 10 Item increments, another might want to page through with 100 elements per page. So I can't have a clustering key that represents a page range.
What I was thinking about doing was saving the paginationState in a separate table along with limit/offset info of the last query the paginationState originated from so I can use the last paginationState to continue the iteration from if the customer requests the next page with the same limit but a different offset. This breaks down if the customer does a cold offset=1000 request but that's something I can throw error messages for at, what I do need to support is a customer doing Request 1: offset=0 + limit=100 Request 2: offset=100 + limit=100 Request 3: offset=200 + limit=100 So next question would be: How long is the paginationState from the driver current? I was thinking about inserting the paginationState with a TTL into another Cassandra table - not sure if that's smart though. greetings Daniel On Tue, 3 Oct 2017 at 12:20 kurt greaves <k...@instaclustr.com> wrote: > I get the impression that you are paging through a single partition in > Cassandra? If so you should probably use bounds on clustering keys to get > your "next page". You could use LIMIT as well here but it's mostly > unnecessary. Probably just use the pagesize that you intend for the API. > > Yes you'll need a table for each sort order, which ties into how you would > use clustering keys for LIMIT/OFFSET. Essentially just do range slices on > the clustering keys for each table to get your "pages". > > Also I'm assuming there's a lot of data per partition if in-mem sorting > isn't an option, if this is true you will want to be wary of creating large > partitions and reading them all at once. Although this depends on your data > model and compaction strategy choices. > > On 3 October 2017 at 08:36, Daniel Hölbling-Inzko < > daniel.hoelbling-in...@bitmovin.com> wrote: > >> Hi, >> I am currently working on migrating a service that so far was MySQL based >> to Cassandra. >> Everything seems to work fine so far, but a few things in the old >> services API Spec is posing some interesting data modeling challenges: >> >> The old service was doing Limit/Offset pagination which is obviously >> something Cassandra can't really do. I understand how paginationState works >> - but so far I haven't figured out a good way to make Limit/Offset work on >> top of paginationState (as I need to be 100% backwards compatible). >> The only ways which I could think of to make Limit/Offset work would >> create scalability issues down the road. >> >> The old service allowed sorting by any field. If I understood correctly >> that would require a table for each sort order right? (In-Mem sorting is >> not an option unfortunately) >> In doing so, how can I make the Java Datastax mapper save to another >> table (I really don't want to be writing a Subclass of the Entity for each >> Table to add the @Table annotation. >> >> greetings Daniel >> > >
