reactions index left out on purpose?

[r10s]

during working on showing reactions in summaries i noticed that there is no sql-index over any reactions column - where we were adding index otherwise on even smaller tables - and reactions table can become quite big, it is only currently small as it is a new feature :)

also, the reaction table is queried often - at least for every message and every chatlist item displayed.

reactions use the following statements that need a full scan currently:

SELECT contact_id, reaction FROM reactions WHERE msg_id=?
SELECT reaction             FROM reactions WHERE msg_id=? AND contact_id=?
SELECT reaction             FROM reactions WHERE msg_id=? AND contact_id=?
DELETE                      FROM reactions WHERE msg_id=? AND contact_id=?

all of them could benefit from an index over msg_id - combined index is probably over the top as the most often called query is the first one.

wondering if the index was left out on purpose? cc @iequidoo @link2xt - otherwise, we should add one with CREATE INDEX reactions_index1 ON reactions(msg_id)

EDIT: or does the FOREIGN KEY(msg_id) imply an index? my source of truth is the sqlite3browser, maybe i've also overseen sth

[iequidoo]

I don't see in the SQLite docs that FOREIGN KEY implies an index. So, an index over msg_id is indeed worth being created