The spool listing already joins spool -> filament -> vendor, so joined
eager loading of all three `extra` collections multiplied their rows
together. With ~12 spool, ~9 filament and ~9 vendor extra fields, a
single GET /spool?limit=30 made the database materialize ~35k wide rows
(one per field combination) and then spent most of its time in
SQLAlchemy de-duplicating them back into 30 objects.
Switch the three `extra` relationships to lazy="selectin" so each
collection is fetched in its own WHERE id IN (...) query and nothing
multiplies. Measured on a 4911-spool SQLite database, GET /spool?limit=30
drops from 431 ms to 12 ms and limit=100 from 1358 ms to 23 ms, with
byte-identical responses across the spool/filament/vendor/group/search
endpoints and all 371 integration tests green on SQLite, PostgreSQL,
MariaDB and CockroachDB.
Claude-Session: https://claude.ai/code/session_014Cwk5Yyze9yPvkYkUtMAP4
The used filament weight is now kept track of instead of remaining weight. This adds robustness to measurement errors which could accumulate and then the filament usage wouldn't get tracked anymore once the weight hit 0. Now it will just keep going.
Donkie