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by dinkledunk 1393 days ago
how to jump to an arbitrary page?
5 comments

You can do that with postgres histograms https://www.citusdata.com/blog/2016/03/30/five-ways-to-pagin... - go to the section "Keyset with Estimated Bookmarks"

> As we saw, plain keyset pagination offers no facility to jump a certain percentage into the results except through client guesswork. However the PostgreSQL statistics collector maintains per-column histograms of value distribution. We can use these estimates in conjunction with limits and small offsets to get fast random-access pagination through a hybrid approach.

Jumping to a specific page is a bit of an ambiguous / undefined term in this case. Like asking for a specific page in a book that's still being written. Maybe today the plot twist occurred on page 100, but then the author decides chapter 1 needs more backstory, and now the plot twist happens on page 115.

Unless you can guarantee your data is static, or that the sorting order cannot be mutated and only append later values, the concept of what data belongs in which page could be changing every millisecond.

Do you really need to jump to an arbitrary page and land on the exact item? For many applications an approximate jump is fine. If your column is fairly uniformly distributed you can guess the index for any arbitrary page.
Yes, my business users will feel like they don't have sufficient access to their data if they can't.

> If your column is fairly uniformly distributed you can guess the index for any arbitrary page.

I don't think that'll work in a multi-tenancy situation with complex filters.

I bet your users does not always know what is best for them.
Some people thoroughly enjoy a linear saccade search! See for example any social media app.

It definitely isn’t in the users’ best interest to have any method of scrolling through a lot of records.

You don't, but instead you can jump to an arbitrary place in the results. For example, you could show results starting from the letter P, or show results starting from 2022-04-02.
Spoiler: you can’t.
But the entire concept is that this is an adaptation to the fact that data may be added to or removed from the database. If that's true, there would be no benefit in jumping to a specific page - there's no guarantee that that page will display any particular data.