snort/dev-docs/query.md

Reactions

Problem

When presented with a feed of notes, either a timeline (social) or a live chat log (live stream chat) how do you fetch the reactions to such notes and maintain realtime updates.

Current solution

When a list of reactions is requested we use the expensive buildDiff operation to compute a list of new (added) filters and send them to relays.

Usually if leaveOpen is specified (as it should be for realtime updates) this new trace will be sent as a separate subscription causing exhasution.

Another side effect of this this approach is that over time (especially in live chat) the number of filters that get passed to buildDiff increases and so the computation time takes longer and causes jank (Kieran/zap.stream#126).

There is also the question of updating the "root" query, since this is not updated, each independant query trace receives its own set of updates which is a problem of its own.

Proposed solution (Live chat)

The ideal solution is to update only the "root" query as new filters are detected along with appending the current timestamp as the since value.

In this way only 1 subscription is maintained, the "root" query trace.

Each time a new set of filters is created from buildDiff we push the same REQ again with the new filters which should result in no new results from the relays as we expect there to be none since the current time is the time of the latest message.

Proposed solution (Timeline)

TBD