Specify the frecency threshold for fetching the top frecent sites

[gabrielluong]

In mozilla-mobile/fenix#14302, we are looking at following iOS and Desktop's frecency threshold to determine which visited sites should be displayed as a visited top site (autogenerated). Currently, we don't expose frecency despite fetching it in the query:

application-services/components/places/src/storage/history.rs

Line 1211 in 6627981

"SELECT h.frecency, h.title, h.url

application-services/components/places/src/places_msg_types.proto

Line 200 in 673e700

message TopFrecentSiteInfo {

This issue is to return the frecency value in the TopFrecentSiteInfo so that AC/Fenix can filter the returned top sites by a given frecency threshold.

┆Issue is synchronized with this Jira Task
┆Story Points: 5
┆Epic: a-s consumer issues
┆Sprint: Backlog

[mhammond]

One concern we've historically had with this is that the value for frecency isn't meaningful as an absolute value - it's only meaningful in its relationship to other values. It also means it will be much trickier to adjust the implementation (eg, see #610) How will you determine what frecency threshold to use? What will you do when there are too few or too many sites for a specific value?

IOW, I'm wondering if there is a better way to implement this than exposing an arbitrary value that we'd prefer to keep as an implementation detail?

[gabrielluong]

One concern we've historically had with this is that the value for frecency isn't meaningful as an absolute value - it's only meaningful in its relationship to other values. It also means it will be much trickier to adjust the implementation (eg, see #610) How will you determine what frecency threshold to use? What will you do when there are too few or too many sites for a specific value?

Ed (mardak) pointed me to the desktop threshold https://searchfox.org/mozilla-central/rev/919607a3610222099fbfb0113c98b77888ebcbfb/browser/components/newtab/lib/TopSitesFeed.jsm#79 with an added note: frecency of a typed in url gets a frecency score of… 2000 vs a link visit gets frecency score of 100

I am still investigating what iOS is doing, but right now if Fenix wanted to conform to desktop. We would simply expose the frecency score and use the same threshold.

[gabrielluong]

Right now, our issue in Fenix is that any visited site is automatically considered a visited top site because we don't use any heuristics to determine the cutoff of what should be considered a visited top site.

[gabrielluong]

I would be open to longer term options. I think the short term plan for Fenix that was conveyed to me was to emulate the iOS and desktop behaviour.

[eoger]

We could also keep the threshold/cut mechanism in the Rust layer so we don't leak the frequency values.

[gabrielluong]

We could also keep the threshold/cut mechanism in the Rust layer so we don't leak the frequency values.

I am still digging around to see what everyone (desktop + iOS) does. Right now, it might be easiest to expose it and let individual consumers decide the threshold and tweak it as appropriate since we're also offering this as a AC component feature (although that might be rare).

[mhammond]

Yeah, I actually think checking just the frecency is going to be wrong whoever does it TBH (maybe a threshold of visit counts would be better, with frecency just used for ordering?) but that's a bigger discussion, and it's hard to argue too hard against this given how desktop etc work, so 🤷‍♂️