Important 1: bucket offsets are now 100 ns ticks as bigint
(DATEDIFF_BIG(microsecond)*10 plus the sub-microsecond tick digits), so a
1601→9999 window no longer overflows (SQL 535) and nothing scales the interval
to nanoseconds in C#. Interval wider than the window clamps to one bucket and
the ceiling division cannot overflow. Exactness to the tick is unchanged.
Important 2 (spec §4 ruling d6afb394): a Bad previous neighbour means the time
is inside an outage — null value with that neighbour's Bad code, never
Uncertain. Usable previous + Bad next still holds the previous value Uncertain.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
SqlServerHistorianDataSource implements IHistorianDataSource over the T8 schema:
raw forward/reverse/point with the 0 = unbounded sentinel; AtTime in one statement
(TimeRow TVP + two OUTER APPLYs) with linear/stepped/no-prior rules and no
interpolation across a Bad neighbour or Empty outage marker; events with a
maxEvents+1 truncation probe and a non-null continuation point; processed
aggregates pushed down to T-SQL (SqlAggregateQueries) with nanosecond-exact
bucket edges, Calculated bits on every result, Uncertain on any non-Good input,
BadAggregateInvalidInputs for numeric aggregates over String/DateTime, a
100 000-bucket cap and HistoryAggregateNotSupportedException for the rest.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Joseph Doherty