Plan değişimi P440

(@condition nvarchar(4000),@incTest bit,@types1 nvarchar(4000),@sid int,@dbName nvarchar(4000),@tag nvarchar(4000),@top int)SELECT TOP (@top) c.ChunkId, c.DocId, d.SourceType, d.SourceRef, d.Title, c.Heading, c.Text, CAST(ft.[RANK] AS float) AS Score
FROM CONTAINSTABLE(rag.Chunk, Text, @condition) AS ft
JOIN rag.Chunk AS c ON c.ChunkId = ft.[KEY]
JOIN rag.Document AS d ON d.DocId = c.DocId
WHERE (d.IsActive = 1 OR (@incTest = 1 AND d.ExclusionReason = 'TestDb')) AND d.SourceType IN (@types1)
AND (@sid IS NULL OR d.ServerID = @sid) AND (@dbName IS NULL OR d.DatabaseName = @dbName)
AND (@tag IS NULL OR EXISTS (SELECT 1 FROM STRING_SPLIT(d.Tags, ',') AS t WHERE LTRIM(RTRIM(t.value)) = @tag))
ORDER BY ft.[RANK] DESC, c.ChunkId

Plan change case #P440 | DB: DB-11 | Improvement | Confidence: Medium (review pending)
Query: (@condition nvarchar(?),@incTest bit,@types1 nvarchar(?),@sid int,@dbName nvarchar(?),@tag nvarchar(?),@top int)SELECT TOP (@top) c.ChunkId, c.DocId, d.SourceType, d.SourceRef, d.Title, c.Heading, c.Text, CAST(ft.[RANK] AS float) AS Score FROM CONTAINSTABLE(rag.Chunk, Text, @condition) AS ft JOIN rag.Chunk AS c ON c.ChunkId = ft.[KEY] JOIN rag.Document AS d ON d.DocId = c.DocId WHERE (d.IsActive = ? OR (@incTest = ? AND d.ExclusionReason = ?)) AND d.SourceType IN (@types1) AND (@sid IS NULL OR d.ServerID = @sid) AND (@dbName IS NULL OR d.DatabaseName = @dbName) AND (@tag IS NULL OR EXISTS (SELECT ? FROM STRING_SPLIT(d.Tags, ?) AS t WHERE LTRIM(RTRIM(t.value)) = @tag)) ORDER BY ft.[RANK] DESC, c.ChunkId
Change: 2026-10-06 16:00 UTC, plan 64743 → 64746, pattern: Transition
Impact (Query Store, per execution): duration 44.5 → 29.1 ms (-35%); CPU 44.3 → 29 ms (-35%); reads 24,504 → 17,850 (-27%); rows 16.04 → 16.55 (+3%)
Plan difference: no operator-level difference
Candidate cause: STATS — Statistic rag.Chunk.PK_Chunk was updated 2026-10-05 22:47 (sampled 47.4%); 3 updates in the window; the plans use this statistic.
Candidate cause: STATS — Statistic rag.Chunk.UQ_Chunk_DocSeq was updated 2026-10-05 22:47 (sampled 50.7%); 3 updates in the window; the plans use this statistic.
Candidate cause: STATS — Statistic rag.Chunk._WA_Sys_00000003_49309088 was updated 2026-10-05 22:47 (sampled 47.4%); 3 updates in the window; the plans use this statistic.
Candidate cause: STATS — Statistic rag.Document.PK_Document was updated 2026-10-06 01:16 (sampled 100%); 2 updates in the window; the plans use this statistic.
Candidate cause: STATS — Statistic rag.Document.UQ_Document_Source was updated 2026-10-06 04:00 (sampled 100%); 3 updates in the window; the plans use this statistic.
Candidate cause: STATS — Statistic rag.Document._WA_Sys_0000000A_428392F9 was updated 2026-10-05 22:57 (sampled 100%); 2 updates in the window; the plans use this statistic.
Candidate cause: STATS — Statistic rag.Document._WA_Sys_00000005_428392F9 was updated 2026-10-05 22:46 (sampled 100%); 2 updates in the window; the plans use this statistic.
Candidate cause: STATS — Statistic rag.Document._WA_Sys_0000000E_428392F9 was updated 2026-10-06 05:48 (sampled 100%); 3 updates in the window; the plans use this statistic.
Counter-evidence: none
Confidence rationale: Medium: a single candidate (STATS), not mechanical (no direct link to the plan is proven).
Note: this is a candidate cause, not proof of the root cause.