[sigmaml]

You appear to be referring to a database cursor.

It is quite simple to implement pagination in the application layer using a unique record identifier (primary key or ULID or ...) as an anchor for the navigation. From that unique ID, we can then fetch the previous `n` or the next `n` records, depending on the direction of the navigation.

This way, the server remains stateless, since the anchor (possibly sent as an encoded / obfuscated token, which can include some other parameters such as page size) is supplied by the client with each pagination request.

Unless I am missing something in your argument.

[borrow]

What if that particular unique ID is deleted right before the client requests the next page?

[JimDabell]

Pagination only makes sense in the context of an ordered collection; if there is no stable sort order then you can’t paginate. So you identify the last record seen with whatever fields you are ordering by, and if the last record has been deleted, then it doesn’t matter because you are only fetching the items greater than those values according to the sort order.

Anyway, there is plenty of documentation out there for cursor-based pagination; Hacker News comments isn’t the right place to explain the implementation details.

[sigmaml]

1. This kind of pagination can be done for any key as long as its data type admits total ordering.

2. The WHERE condition typically uses `>` or `<`, so it doesn't fail even when that record is deleted before the next client request referring to it.

[pronik]

If the IDs are monotonous, it doesn't matter.

[rattray]

(for posterity, this appears to have been a typo for monotonic)