Results pagination in Cassandra (CQL)

Question

I am wondering how can I achieve pagination using Cassandra.

Let us say that I have a blog. The blog lists max 10 posts per page. To access next posts a user must cl

Answer 1

Although the count is available in CQL, so far I have not seen a good solution for the offset part...

So... one solution I have been contemplating was to create sets of pages using a background process.

In some table, I would create the blog page A as a set of references to page 1, 2, ... 10. Then another entry for blog page B pointing to pages 11 to 20, etc.

In other words, I would build my own index with a row key set to the page number. You may still make it somewhat flexible since you can offer the user to choose to see 10, 20 or 30 references per page. For example, when set to 30, you display sets 1, 2, and 3 as page A, sets 4, 5, 6 as page B, etc.)

And if you have a backend process to handle all of that, you can update your lists as new pages are added and old pages are deleted from the blog. The process should be really fast (like 1 min. for 1,000,000 rows if even that slow...) and then you can find the pages to display in your list pretty much instantaneously. (Obviously, if you are to have thousands of users each posting hundreds of pages... that number can grow quickly.)

Where it becomes more complicated is if you wanted to offer a complex WHERE clause. By default a blog shows you a list of all the posts from the newest to the oldest. You could also offer lists of posts with tag Cassandra. Maybe you want to inverse the order, etc. That makes it difficult unless you have some form of advanced way to create your index(es). On my end I have a C-like language which goes and peek and poke to the values in a row to (a) select them and if selected (b) to sort them. In other words, on my end I can already have WHERE clauses as complex as what you'd have in SQL. However, I do not yet break up my lists in pages. Next step I suppose...