在执行计划之前(因为我正在调试一个运行不佳的计划),我有这个变量赋值块:
DECLARE @Days INT = 180
DECLARE @DateRangeFrom DateTime = DATEADD(d, -@Days, getDate())
DECLARE @DateRangeTo DateTime = getDate()
DECLARE @FacilityID INT = 1010
DECLARE @Answer0 INT = 1879
DECLARE @Answer1 INT = 1949
DECLARE @Answer1SetID INT = 1607
DECLARE @Answer2 INT = 1907
DECLARE @Answer2SetID INT = 1593
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我的第一个问题是在 IRItemAnswer_Info 表(节点 ID 19)上执行的查找。它溢出到 Tempdb,它已经以错误的方式开始查询。它引用IRItemAnswerInfo_DGItemID_AnswerSourceID索引,这是正确的索引,因为我正在匹配DGItemID和AnswerSourceID,然后返回IncidentID。索引创建为
CREATE NONCLUSTERED INDEX IRItemAnswerInfo_DGItemID_AnswerSourceID
ON dbo.IRItemAnswer_Info (DGItemID, AnswerSourceID)
INCLUDE([IncidentID], [AnswerBoolean])
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但是,查询的估计行数为 53,459,实际行数为 969,812。
我刚刚完成强制通过新的统计数据UPDATE STATISTICS IRItemAnswer_Info …
sql-server execution-plan cardinality-estimates sql-server-2019 query-performance
sql-server ×1