The `inboxes#index` API endpoint was firing 3 queries per inbox while
rendering the response — one each for the polymorphic channel, avatar
attachment, and working hours. For accounts with many inboxes this
turned a routine list call into a multi-second request — measured at 35
seconds on an account with 5,000 inboxes.
Two root causes:
1. `policy_scope` was silently discarding the controller's
`.includes(...)` chain because `InboxPolicy::Scope#resolve` returns a
fresh `user.assigned_inboxes` relation, ignoring whatever scope is
passed in. So the eager loading never actually applied.
2. `Inbox#weekly_schedule` called `working_hours.order(...).select(...)`
which fires a new query per inbox even when the association is
preloaded.
The fix chains the eager loads and ordering after `policy_scope` so they
apply to the relation the policy actually returns, adds `:portal` and
`:working_hours` to the preload list, and refactors `weekly_schedule` to
sort the preloaded collection in Ruby and build the hash directly.
Result: queries drop from O(n) to a constant ~15 regardless of inbox
count, and total request time drops 5–6× across every account size
tested. Response payload is byte-identical.
## How to test
1. Open the agent dashboard for an account with a large number of
inboxes (1000+). On a stock dev DB you can seed quickly with
`Seeders::AccountSeeder` or by creating a few hundred `Channel::Api`
inboxes via the rails console.
2. Hit any UI surface that lists inboxes (settings → inboxes, sidebar
inbox list, agent assignment dropdowns). Should feel near-instant where
it previously hung.
3. Confirm every inbox shows the same data as before — channel type,
working hours, avatar, portal/help-center link. No fields should be
missing or different.
## Benchmarks
Real HTTP requests via curl against a dev Rails server (median of 5
timed trials after warmup; "Server total" is the time reported in Rails'
`Completed 200 OK in <X>ms` log line).
| Account | Channel mix | OLD | NEW | Speedup |
|---|---|---|---|---|
| 1000 inboxes | 3 types, no portals/avatars | 5.87 s | 0.96 s |
**6.1×** |
| 5000 inboxes | 3 types, no portals/avatars | 33.07 s | 6.93 s |
**4.8×** |
| 5000 inboxes | 10 types, 25% portals, 10% avatars | 35.04 s | 6.55 s |
**5.4×** |
Detailed breakdown for the realistic 5000-inbox case:
| | OLD | NEW | Δ |
|-----------------|-----------|----------|----------|
| Server total | 35,042 ms | 6,550 ms | −81% |
| Views | 32,034 ms | 6,452 ms | −80% |
| ActiveRecord | 2,948 ms | 92 ms | −97% |
| Allocations | 42.3 M | 11.3 M | −73% |
| Queries | ~15,000 | 15 | −99.9% |
## What changed
- `app/controllers/api/v1/accounts/inboxes_controller.rb` — chain
`.includes(:channel, :portal, :working_hours, avatar_attachment:
:blob).order_by_name` *after* `policy_scope(...)`. The previous code
passed them into `policy_scope` but the policy resolver dropped the
chain.
- `app/models/concerns/out_of_offisable.rb` — `weekly_schedule` now
sorts the preloaded `working_hours` collection in Ruby and constructs
the result hashes inline, avoiding both the per-inbox query from
`.order(...).select(...)` and the `as_json` reflection overhead.
Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>
