fix: outbox KPI per-status legs, composite event-log indexes, AuditLog ingest FORCESEEK (#122, #123, #124)

#122: the Notification Outbox KPI snapshots ORed every status in one aggregation, which scanned the clustered index once the table held ~1 M Parked rows (0.7-2.6 s; Health dashboard up to 5 s). Each snapshot now runs three status-equality legs that seek their own index (~0.12 s); a cold Health load on the rig is 0.12-0.52 s. #123: site_events event_type/severity indexes are now composites with timestamp, so a filtered page is read in order and stops at the limit (severity=Error over 1 GB: 2,287 -> 15 ms cold, 115 -> 1.6 ms warm). Costs 454 -> 530 B/row, ~14 % fewer rows under the same cap. The schema apply drops the old indexes in place; the cap size model samples timestamp three times and re-scores inside its band with unchanged constants. #124: the set-based AuditLog insert's NOT EXISTS probe scanned the EventId index and concurrent writers deadlocked on S/IX page locks. WITH (FORCESEEK): 4 writers 775 rows/s + 76 deadlocks in 30 s -> 5,214 rows/s + 0. New concurrent-writer regression test fails 4/4 without the hint.
2026-11-10 16:46:42 -05:00
parent 2b80a6defa
commit 424db1555d
12 changed files with 386 additions and 158 deletions
@@ -171,6 +171,24 @@ stream whose row width changes sharply *in the middle* of the history — neithe
 tail — is mis-sized until the trim reaches it. Self-correcting in practice, since the cap is
 re-evaluated every tick and the head sample advances as the oldest rows go.

+### 3.2 Recalibration for the composite indexes (#123, 2026-11-10)
+
+#123 replaced the single-column `event_type` and `severity` indexes with `(event_type, timestamp)`
+and `(severity, timestamp)`. There are still four secondary indexes, so `IndexedColumnCount = 4`
+stands. The sampler's `indexed_bytes` now counts `timestamp` three times: once for its own index
+and once for each composite. The other constants are unchanged.
+
+The model was re-scored with `EstimateSiteEventsSize_TracksTheRealFootprint`:
+
+| Workload | estimated | actual | error | before #123 |
+| --- | ---: | ---: | ---: | ---: |
+| narrow rows, no details | 3 859 626 | 3 551 232 | **+8.7 %** | +8.4 % |
+| typical rows, 200 B details | 4 520 096 | 4 005 888 | **+12.8 %** | +12.8 % |
+| wide rows, 2 KB details | 13 012 048 | 13 078 528 | **−0.5 %** | −0.8 % |
+
+The band and the high bias are unchanged. `SiteEventsSchemaCalibrationTests` pins the new index
+set and the columns each index covers.
+
 ## 4. The wipe-prevention guard, restated

 The register asked whether the "size did not decrease" guard should survive. It should, and it