ash
ash copied to clipboard
ash-project
Support a "fetch" style of keyset pagination that allows complex sorts in conjunction
Due to the filter-based implementation of keyset pagination, it cannot be used with sorts on calculations.
We could solve this problem by making the keyset only be the primary key of the record, and then fetching that value loading the calculations/aggregates that we need. If we do this we should either: 1.) make it a new pagination mode or 2.) add an option like mode: :strict | :fetch (name TBD)to pagination options.
Let me know if you're reading this and want to help implement it.
More on ash pagination: https://hexdocs.pm/ash/pagination.html#keyset-pagination
Keyset pagination currently works by taking all of the fields being sorted on and their values and building it into a binary. There are a couple potential problems with this approach, for example if someone sorted on a massive text field we may have a problem. So we want to add this alternative message for a few different reasons. By limiting the keyset to only the primary key, we have to refetch the record, including loading any calculations/aggregates that are being used in the query. Then we can build the query to fetch everything after that record.
So I've switched the underlying code to use this new fetch style. We will solve separately for the more_previous? concept in #334
CI is failing because of this line: https://github.com/ash-project/ash/commit/64b3312cb94869d3ef9b25a11658e056c7191380#diff-dfa6f4ed74c90e5d4fda283d547d366586e690387289bcfd473e3fa5f9ace308R223
