sys.dm_db_index_usage_stats also starts over when a database is taken
offline, closed by AUTO_CLOSE or (2012/2014) an index is rebuilt. The
delta was then clamped to 0, so the usage since the reset was lost from
the daily history and the tracked totals. A lower counter now counts as
new usage. IndexInfo.Key also used the literal text "001f" as its
separator instead of the unit separator character.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
The index collector now sums index reads and writes between collections
across restarts of SQL Server (and of the agent, by seeding from the
stored snapshot) and keeps them per day in insight.IndexUsageDaily
(migration 0015, HourlyDays). SQLI-IDX-002 judges an index once it has
been followed for 7 days instead of needing 7 days of uptime.
GET /api/v1/instances/{name}/index-usage lists usage per index.
SQLI-STAT-001 also reports statistics that were never updated on tables
with rows; statistic rows now come from the table's heap or clustered
index, as a never-updated statistic has no row count of its own.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Collector (every 6 h, metadata and DMVs only, no scans): index inventory
with usage and forwarded fetches, missing-index suggestions, statistics
modifications via sysindexes.rowmodctr (needs only metadata visibility).
Rules:
- SQLI-IDX-001 missing index, evaluated against existing indexes:
extends an index with the same keys instead of adding one; notes on
write-heavy tables, many indexes, wide includes, short uptime
- SQLI-IDX-002 unused index (needs 7 days of uptime; suggests DISABLE)
- SQLI-IDX-003 duplicate or covered index (filters, uniqueness respected)
- SQLI-IDX-004 heap with forwarded records
- SQLI-STAT-001 stale statistics, SQLI-STAT-002 auto statistics off
Column lists use U+E000 as separator: FOR XML cannot serialize NCHAR(1).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E3EExwndy8Z22EK2Qpt6BK
