The user directory is currently maintained based on the 'visible' users on this particular server - i.e. ones which your account shares a room with, or who are present in a publicly viewable room present on the server.
The directory info is stored in various tables, which can (typically after
DB corruption) get stale or out of sync. If this happens, for now the
solution to fix it is to use the admin API
and execute the job
regenerate_directory. This should then start a background task to
flush the current tables and regenerate the directory.
There are five relevant tables that collectively form the "user directory". Three of them track a master list of all the users we could search for. The last two (collectively called the "search tables") track who can see who.
From all of these tables we exclude three types of local user:
user_directory. This contains the user_id, display name and avatar we'll
return when you search the directory.
user_directory_search. To be joined to
user_directory. It contains an extra
column that enables full text search based on user ids and display names.
Different schemas for SQLite and Postgres with different code paths to match.
user_directory_stream_pos. When the initial background update to populate
the directory is complete, we record a stream position here. This indicates
that synapse should now listen for room changes and incrementally update
the directory where necessary.
users_in_public_rooms. Contains associations between users and the public rooms they're in.
Used to determine which users are in public rooms and should be publicly visible in the directory.
users_who_share_private_rooms. Rows are triples
(L, M, room id) where
is a local user and
M is a local or remote user.
M should be
different, but this isn't enforced by a constraint.