@cooltey I tried to reproduce but was able to get like-results for both requests around 162ms response times. Could you please provide more information on how you are making requests?

zhwiki

In T271145#6722561, @sdkim wrote:

@cooltey I tried to reproduce but was able to get like-results for both requests around 162ms response times. Could you please provide more information on how you are making requests?

Hi @sdkim,
I have updated the description and looks like it will happen when making the request with Accept-Language, please see the screenshots in the description.

Thanks @cooltey , since the logic behind this is RESTbase I've tagged platform engineering

We don't store language variant transformations in RESTBase - they are done on the fly. Given that /page/related needs to compute summaries for many articles in variants, no wonder it can be slow.

Fixing it in RESTBase would be a VERY significant investment and generally goes against the idea of sunsetting RESTBase. If this is a very big deal we need to invest time into moving this endpoint into Core REST API and adding proper caching there.

RESTBase just seems to proxy to the Action API with no caching. It uses generator=search with a "morelike" operator in the search query.

In T271145#6723895, @tstarling wrote:

RESTBase just seems to proxy to the Action API with no caching. It uses generator=search with a "morelike" operator in the search query.

Yeah. And then after It looks up summaries for the articles stored in cassandra, merges them in and returns the result. When summaries are coming from storage it's all very fast, but in case of language variants stored summaries need to be converted via parsoid, so it becomes very slow.

What is the user impact? Is this endpoint used by something?

In T271145#6723939, @tstarling wrote:

What is the user impact? Is this endpoint used by something?

It is used by the Wikipedia Android and iOS app for two places.
One is the "Because you read" feed card on the Explore feed, and the other one is the footer of the mobile-html which shows related pages in "Read more" section.