-- ===================================================================================================================
-- SQLI-QS-002: Forceret plan kan ikke bruges
-- ===================================================================================================================
-- Regel-id:    SQLI-QS-002
-- Titel:       Forceret plan kan ikke bruges
-- Alvor:       High
-- Versioner:   SQL Server 2016 og nyere (Query Store).
--
-- Hvad tjekkes, og hvorfor:
--   Om en plan, der er forceret i Query Store, ikke længere kan bruges (fx fordi et index er fjernet).
--
-- Vurdering (sker i C# ud fra de indsamlede data, ikke i SQL'en, medmindre andet er nævnt):
--   Ét fund pr. plan med is_forced_plan = 1 og force_failure_count > 0 (højst 10).
--
-- Grænseværdier (konfigurationsnøgle i agentens appsettings.json og standardværdi):
--   Ingen.
--
-- Rettigheder til agentens login (se db/permissions/grant-least-privilege.sql; [agent] = agentens login):
--   GRANT VIEW SERVER STATE TO [agent];                -- SQL Server 2005-2019
--   GRANT VIEW SERVER PERFORMANCE STATE TO [agent];    -- SQL Server 2022+ (erstatter VIEW SERVER STATE)
--   GRANT VIEW SERVER SECURITY STATE TO [agent];       -- SQL Server 2022+
--   GRANT VIEW ANY DEFINITION TO [agent];              -- metadata; giver IKKE adgang til data
--   GRANT CONNECT ANY DATABASE TO [agent];             -- SQL Server 2014+; giver IKKE adgang til data
--   Før 2014 i stedet, i hver brugerdatabase: CREATE USER [agent] FOR LOGIN [agent];
--
-- Data kommer fra (collector, fil : medlemmer, interval):
--   QueryStoreCollector
--     Fil: src/SQLInsight.Collectors/Performance/QueryStoreCollector.cs
--     Medlemmer: QueryStoreCollector.DatabasesSql, QueryStoreCollector.BuildStatsSql(database),
--     QueryStoreCollector.BuildFailedForcedSql(database)
--     Interval: 30 min som standard (SQLInsight:CollectorIntervals:query-store)
--     Delt script: SQL Scripts/_collectors/QueryStoreCollector.sql
-- Regelkode:   src/SQLInsight.Rules/Performance/QueryStoreRules.cs : FailedForcedPlanRule.Evaluate
--
-- Read-only:   Ja: kun SELECT samt lokale variabler, SET-sessionsindstillinger. Intet ændrer data, indstillinger
--              eller objekter.
-- Kørsel:      Kør i SSMS som agentens login (eller et login med samme rettigheder). Hver variant er sin egen batch
--              (GO); en variant for en anden SQL Server-version end din kan fejle - det er forventet.
--              Per-database-forespørgsler er vist for databasen msdb, som findes overalt: ret navnet til den
--              database, du vil se.
-- ===================================================================================================================

-- -------------------------------------------------------------------------------------------------------------------
-- Forbindelsen: Sessionsindstillinger, agenten sætter på hver forbindelse
-- -------------------------------------------------------------------------------------------------------------------

-- Variant: Alle versioner: sættes på hver forbindelse, agenten åbner
-- Kilde: SqlConnectionFactory.SessionSettings
-- Kode:  src/SQLInsight.Connectivity/SqlConnectionFactory.cs : SqlConnectionFactory.SessionSettings
SET LOCK_TIMEOUT 5000; SET DEADLOCK_PRIORITY LOW; SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
GO

-- -------------------------------------------------------------------------------------------------------------------
-- QueryStoreCollector: Query Store i hver brugerdatabase, hvor det er slået til: de 100 tungeste queries over 8 dage
-- og forcerede planer, der fejler.
-- -------------------------------------------------------------------------------------------------------------------

-- Variant: SQL Server 2016 og nyere
-- Kilde: QueryStoreCollector.DatabasesSql
-- Kode:  src/SQLInsight.Collectors/Performance/QueryStoreCollector.cs : QueryStoreCollector.DatabasesSql
SELECT name FROM sys.databases
WHERE is_query_store_on = 1 AND state = 0 AND database_id > 4
GO

-- Variant: SQL Server 2016 og nyere: én gang pr. database med Query Store (vist for msdb)
-- Kilde: QueryStoreCollector.BuildStatsSql
-- Kode:  src/SQLInsight.Collectors/Performance/QueryStoreCollector.cs : QueryStoreCollector.BuildStatsSql(database)
DECLARE @now datetimeoffset = SYSDATETIMEOFFSET();
DECLARE @recent datetimeoffset = DATEADD(hour, -24, @now);
DECLARE @history datetimeoffset = DATEADD(day, -8, @now);

WITH stats AS (
    SELECT p.query_id, p.plan_id,
           CASE WHEN i.start_time >= @recent THEN 1 ELSE 0 END AS is_recent,
           SUM(rs.count_executions) AS execs,
           SUM(rs.avg_duration * rs.count_executions) AS total_duration,
           SUM(rs.avg_cpu_time * rs.count_executions) AS total_cpu,
           SUM(rs.avg_logical_io_reads * rs.count_executions) AS total_reads,
           MAX(rs.stdev_duration) AS max_stdev_duration,
           MAX(rs.max_duration) AS max_duration,
           MIN(rs.min_duration) AS min_duration,
           MAX(rs.last_execution_time) AS last_execution
    FROM [msdb].sys.query_store_runtime_stats rs
    JOIN [msdb].sys.query_store_runtime_stats_interval i ON i.runtime_stats_interval_id = rs.runtime_stats_interval_id
    JOIN [msdb].sys.query_store_plan p ON p.plan_id = rs.plan_id
    WHERE i.start_time >= @history
    GROUP BY p.query_id, p.plan_id, CASE WHEN i.start_time >= @recent THEN 1 ELSE 0 END
), top_queries AS (
    SELECT TOP (100) query_id FROM stats GROUP BY query_id ORDER BY SUM(total_duration) DESC
)
SELECT s.query_id, s.plan_id, s.is_recent, s.execs, s.total_duration, s.total_cpu, s.total_reads,
       s.max_stdev_duration, s.max_duration, s.min_duration,
       CAST(SWITCHOFFSET(s.last_execution, '+00:00') AS datetime2(0)),
       p.is_forced_plan, LEFT(qt.query_sql_text, 2000),
       OBJECT_SCHEMA_NAME(q.object_id, DB_ID(N'msdb')) + N'.' + OBJECT_NAME(q.object_id, DB_ID(N'msdb'))
FROM stats s
JOIN top_queries t ON t.query_id = s.query_id
JOIN [msdb].sys.query_store_plan p ON p.plan_id = s.plan_id
JOIN [msdb].sys.query_store_query q ON q.query_id = s.query_id
JOIN [msdb].sys.query_store_query_text qt ON qt.query_text_id = q.query_text_id;
GO

-- Variant: SQL Server 2016 og nyere: én gang pr. database med Query Store (vist for msdb)
-- Kilde: QueryStoreCollector.BuildFailedForcedSql
-- Kode:  src/SQLInsight.Collectors/Performance/QueryStoreCollector.cs : QueryStoreCollector.BuildFailedForcedSql(database)
SELECT p.query_id, p.plan_id, p.force_failure_count, p.last_force_failure_reason_desc, LEFT(qt.query_sql_text, 2000)
FROM [msdb].sys.query_store_plan p
JOIN [msdb].sys.query_store_query q ON q.query_id = p.query_id
JOIN [msdb].sys.query_store_query_text qt ON qt.query_text_id = q.query_text_id
WHERE p.is_forced_plan = 1 AND p.force_failure_count > 0;
GO