speed up vm trace pages

README.md

@@ -5,6 +5,15 @@ vCTP is a vSphere Chargeback Tracking Platform, designed for a specific customer
 - Hourly snapshots capture inventory per vCenter (concurrency via `hourly_snapshot_concurrency`).
 - Daily summaries aggregate the hourly snapshots for the day; monthly summaries aggregate daily summaries for the month (or hourly snapshots if configured).
 - Snapshots are registered in `snapshot_registry` so regeneration via `/api/snapshots/aggregate` can locate the correct tables (fallback scanning is also supported).
+- vCenter totals pages now provide two views:
+  - Daily Aggregated (`/vcenters/totals/daily`) for fast long-range trends.
+  - Hourly Detail 45d (`/vcenters/totals/hourly`) for recent granular change tracking.
+- vCenter totals performance is accelerated with compact cache tables:
+  - `vcenter_latest_totals` (one latest row per vCenter)
+  - `vcenter_aggregate_totals` (hourly/daily/monthly per-vCenter totals by snapshot time)
+- VM Trace now supports two modes on `/vm/trace`:
+  - `view=hourly` (default) for full snapshot detail
+  - `view=daily` for daily aggregated trend lines (using `vm_daily_rollup` when available)
 - Reports (XLSX with totals/charts) are generated automatically after hourly, daily, and monthly jobs and written to a reports directory.
 - Hourly totals in reports are interval-based: each row represents `[HH:00, HH+1:00)` and uses the first snapshot at or after the hour end (including cross-day snapshots) to prorate VM presence by creation/deletion overlap.
 - Monthly aggregation reports include a Daily Totals sheet with full-day interval labels (`YYYY-MM-DD to YYYY-MM-DD`) and prorated totals derived from daily summaries.
@@ -87,6 +96,11 @@ If you want a one-time cache backfill for the vCenter totals cache tables
 vctp -settings /path/to/vctp.yml -backfill-vcenter-cache
 ```
 
+The backfill command:
+- Ensures/migrates `snapshot_registry` when needed.
+- Rebuilds hourly/latest vCenter totals caches.
+- Recomputes daily/monthly rows for `vcenter_aggregate_totals` from registered summary snapshots.
+
 ## Database Configuration
 By default the app uses SQLite and creates/opens `db.sqlite3`.