AVEVA's native TimeAverage / Total are answered with Good-status wrong values
while the gateway sends the interval in the wrong unit (historiangw#27): one
whole-span value on the earliest interval, the rest absent. Nothing on the
wire marks the answer as degraded.
Both are now refused BadAggregateNotSupported (unsent, not counted as a
backend failure, not advertised in AggregateFunctions) unless
ServerHistorian:Gateway:EnableNativeTimeWeighted is true. The default
Gateway set is the ten raw-evaluated aggregates
(GatewayHistorianDataSource.RawEvaluatedAggregates); ServedAggregates stays
the 12 the backend can serve with the flag on. The native-path tests opt in.
Also documents the ServerHistorian:Gateway sub-section (EventDrainBudget from
the previous commit) and the events drain in docs/Historian.md.
Rebased from the unpushed remed/lane-H2 branch (originally authored 2026-10-22
in session_01Ub9hGmYLQvn9XETzw7CMsT) onto current master.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty