Roadmap M1 R1.7. Filters are set on the native EventQuery object via
AddEventFilter(property, HistorianComparisionType, value) — NOT EventQueryArgs
(time/count/order only). Found via a new harness --dump-type-members command.
Captured the native filtered StartEventQuery pRequestBuff (Capture-EventFilter.ps1 +
harness --event-filter knob) and diffed Equal(0) vs Contains(12) to isolate the
operator field. Filter block (decoded byte-for-byte):
ushort 0 + uint filterCount + uint condCount + uint nameLen + name(UTF-16) +
uint 1 + ushort op + uint 1 + value(0x09-LEN-0x00 compact-ASCII) + byte 0
The filter is REAL, not inert (unlike the analog-summary knobs): a non-matching
predicate returns 0 events; Type=Equal=User.Write returns only User.Write events.
Verified live via both the native harness and the SDK.
- HistorianClient.ReadEventsAsync(start, end, HistorianEventFilter, ct) overload
- HistorianEventFilter + HistorianEventComparison (18 ops, ordinals = native)
- Filter encoding in HistorianEventQueryProtocol (empty-filter path unchanged)
- Golden-byte tests (block match, op field, empty-filter regression) + gated live test
Single string-valued predicate only; multi-filter (OR) / multi-condition (AND via
AddEventFilterCondition) framing is partially captured and not shipped. 216 unit
tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Joseph Doherty
6d470eab4a