Prefer capacity/openresty rollups only when they cover the 24h window;
otherwise merge per hour so raw fills pre-MV gaps and rollup wins on
overlap. Add a one-time ANTI JOIN backfill migration for the last 30 days.
Materialized capacity/openresty hourly tables only hold data after the MV
exists. Preferring any non-empty rollup hid full raw history and left 24h
charts with only recent hours. Use rollup only when its earliest bucket
covers the query window start.
Node and dashboard 24h capacity, network, and disk IO charts only used the
latest limited raw snapshots (120/500 rows), so historical hour buckets stayed
empty. Prefer ClickHouse hourly aggregates with counter deltas, and fall back
to raw snapshots when aggregation is unavailable.
ryan