有人可以就如何改进以下查询的性能提出建议。注意，问题似乎是由where子句引起的。
数据（表包含一组巨大的行--500K +，它被调用的参数集，每个查询返回2-5K记录，目前需要8-10分钟）：
USE [SomeDb]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Data](
[x] [money] NOT NULL,
[y] [money] NOT NULL,
CONSTRAINT [PK_Data] PRIMARY KEY CLUSTERED
(
[x] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
查询
select top 10000
s.x as sx,
e.x as ex,
s.y as sy,
e.y as ey,
e.y - s.y as y_delta,
e.x - s.x as x_delta
from Data s
inner join Data e
on e.x > s.x and e.x - s.x between xFrom and xTo
--where e.y - s.y > @yDelta -- when uncommented causes a huge delay
更新1 - 执行计划
<?xml version="1.0" encoding="utf-16"?>
<ShowPlanXML xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" Version="1.2" Build="11.0.2100.60" xmlns="http://schemas.microsoft.com/sqlserver/2004/07/showplan">
<BatchSequence>
<Batch>
<Statements>
<StmtSimple StatementCompId="1" StatementEstRows="100" StatementId="1" StatementOptmLevel="FULL" StatementOptmEarlyAbortReason="GoodEnoughPlanFound" StatementSubTreeCost="0.0263655" StatementText="select top 100
s.x as sx,
e.x as ex,
s.y as sy,
e.y as ey,
e.y - s.y as y_delta,
e.x - s.x as x_delta
from Data s 
 inner join Data e
 on e.x > s.x and e.x - s.x between 100 and 105
where e.y - s.y > 0.01
" StatementType="SELECT" QueryHash="0xAAAC02AC2D78CB56" QueryPlanHash="0x747994153CB2D637" RetrievedFromCache="true">
<StatementSetOptions ANSI_NULLS="true" ANSI_PADDING="true" ANSI_WARNINGS="true" ARITHABORT="true" CONCAT_NULL_YIELDS_NULL="true" NUMERIC_ROUNDABORT="false" QUOTED_IDENTIFIER="true" />
<QueryPlan DegreeOfParallelism="0" NonParallelPlanReason="NoParallelPlansInDesktopOrExpressEdition" CachedPlanSize="24" CompileTime="13" CompileCPU="13" CompileMemory="424">
<MemoryGrantInfo SerialRequiredMemory="0" SerialDesiredMemory="0" />
<OptimizerHardwareDependentProperties EstimatedAvailableMemoryGrant="52199" EstimatedPagesCached="14561" EstimatedAvailableDegreeOfParallelism="4" />
<RelOp AvgRowSize="55" EstimateCPU="1E-05" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="100" LogicalOp="Compute Scalar" NodeId="0" Parallel="false" PhysicalOp="Compute Scalar" EstimatedTotalSubtreeCost="0.0263655">
<OutputList>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="y" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
<ColumnReference Column="Expr1004" />
<ColumnReference Column="Expr1005" />
</OutputList>
<ComputeScalar>
<DefinedValues>
<DefinedValue>
<ColumnReference Column="Expr1004" />
<ScalarOperator ScalarString="[SomeDb].[dbo].[Data].[y] as [e].[y]-[SomeDb].[dbo].[Data].[y] as [s].[y]">
<Arithmetic Operation="SUB">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="y" />
</Identifier>
</ScalarOperator>
</Arithmetic>
</ScalarOperator>
</DefinedValue>
<DefinedValue>
<ColumnReference Column="Expr1005" />
<ScalarOperator ScalarString="[SomeDb].[dbo].[Data].[x] as [e].[x]-[SomeDb].[dbo].[Data].[x] as [s].[x]">
<Arithmetic Operation="SUB">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
</Identifier>
</ScalarOperator>
</Arithmetic>
</ScalarOperator>
</DefinedValue>
</DefinedValues>
<RelOp AvgRowSize="39" EstimateCPU="1E-05" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="100" LogicalOp="Top" NodeId="1" Parallel="false" PhysicalOp="Top" EstimatedTotalSubtreeCost="0.0263555">
<OutputList>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="y" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="100" ActualEndOfScans="1" ActualExecutions="1" />
</RunTimeInformation>
<Top RowCount="false" IsPercent="false" WithTies="false">
<TopExpression>
<ScalarOperator ScalarString="(100)">
<Const ConstValue="(100)" />
</ScalarOperator>
</TopExpression>
<RelOp AvgRowSize="39" EstimateCPU="151828" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="100" LogicalOp="Inner Join" NodeId="2" Parallel="false" PhysicalOp="Nested Loops" EstimatedTotalSubtreeCost="0.0263455">
<OutputList>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="y" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="100" ActualEndOfScans="0" ActualExecutions="1" />
</RunTimeInformation>
<NestedLoops Optimized="false">
<OuterReferences>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
</OuterReferences>
<RelOp AvgRowSize="23" EstimateCPU="1.80448" EstimateIO="3.76461" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="1" LogicalOp="Clustered Index Scan" NodeId="3" Parallel="false" PhysicalOp="Clustered Index Scan" EstimatedTotalSubtreeCost="0.0032831" TableCardinality="1640290">
<OutputList>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="15225" ActualEndOfScans="0" ActualExecutions="1" />
</RunTimeInformation>
<IndexScan Ordered="false" ForcedIndex="false" ForceScan="false" NoExpandHint="false">
<DefinedValues>
<DefinedValue>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
</DefinedValue>
<DefinedValue>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
</DefinedValue>
</DefinedValues>
<Object Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Index="[PK_Data]" Alias="[e]" IndexKind="Clustered" />
</IndexScan>
</RelOp>
<RelOp AvgRowSize="23" EstimateCPU="0.902317" EstimateIO="1.88387" EstimateRebinds="1" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="100" LogicalOp="Clustered Index Seek" NodeId="4" Parallel="false" PhysicalOp="Clustered Index Seek" EstimatedTotalSubtreeCost="0.0263655" TableCardinality="1640290">
<OutputList>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="y" />
</OutputList>
<RunTimeInformation>
<RunTimeCountersPerThread Thread="0" ActualRows="100" ActualEndOfScans="15224" ActualExecutions="15225" />
</RunTimeInformation>
<IndexScan Ordered="true" ScanDirection="FORWARD" ForcedIndex="false" ForceSeek="false" ForceScan="false" NoExpandHint="false" Storage="RowStore">
<DefinedValues>
<DefinedValue>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
</DefinedValue>
<DefinedValue>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="y" />
</DefinedValue>
</DefinedValues>
<Object Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Index="[PK_Data]" Alias="[s]" IndexKind="Clustered" />
<SeekPredicates>
<SeekPredicateNew>
<SeekKeys>
<EndRange ScanType="LT">
<RangeColumns>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
</RangeColumns>
<RangeExpressions>
<ScalarOperator ScalarString="[SomeDb].[dbo].[Data].[x] as [e].[x]">
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
</Identifier>
</ScalarOperator>
</RangeExpressions>
</EndRange>
</SeekKeys>
</SeekPredicateNew>
</SeekPredicates>
<Predicate>
<ScalarOperator ScalarString="([SomeDb].[dbo].[Data].[x] as [e].[x]-[SomeDb].[dbo].[Data].[x] as [s].[x])>=($100.0000) AND ([SomeDb].[dbo].[Data].[x] as [e].[x]-[SomeDb].[dbo].[Data].[x] as [s].[x])<=($105.0000) AND ([SomeDb].[dbo].[Data].[y] as [e].[y]-[SomeDb].[dbo].[Data].[y] as [s].[y])>(0.01)">
<Logical Operation="AND">
<ScalarOperator>
<Compare CompareOp="GE">
<ScalarOperator>
<Arithmetic Operation="SUB">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
</Identifier>
</ScalarOperator>
</Arithmetic>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="($100.0000)" />
</ScalarOperator>
</Compare>
</ScalarOperator>
<ScalarOperator>
<Compare CompareOp="LE">
<ScalarOperator>
<Arithmetic Operation="SUB">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="x" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="x" />
</Identifier>
</ScalarOperator>
</Arithmetic>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="($105.0000)" />
</ScalarOperator>
</Compare>
</ScalarOperator>
<ScalarOperator>
<Compare CompareOp="GT">
<ScalarOperator>
<Arithmetic Operation="SUB">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[e]" Column="y" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[SomeDb]" Schema="[dbo]" Table="[Data]" Alias="[s]" Column="y" />
</Identifier>
</ScalarOperator>
</Arithmetic>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="(0.01)" />
</ScalarOperator>
</Compare>
</ScalarOperator>
</Logical>
</ScalarOperator>
</Predicate>
</IndexScan>
</RelOp>
</NestedLoops>
</RelOp>
</Top>
</RelOp>
</ComputeScalar>
</RelOp>
</QueryPlan>
</StmtSimple>
</Statements>
</Batch>
</BatchSequence>
</ShowPlanXML>
答案 0 :(得分：5)
我经常看到通过将第一个查询的结果（在没有where子句的情况下）插入到TEMP表或表变量中，然后从中选择（这基本上有助于查询优化器选择）来获得巨大的性能提升适当的执行计划）。
还注意到你在Y列上没有INDEX，这可能会加快一点。
修改 另外，尝试以下（给我稍微好一点的性能）：
SELECT * FROM
(SELECT
s.x as sx,
e.x as ex,
s.y as sy,
e.y as ey,
e.y - s.y as y_delta,
e.x - s.x as x_delta
FROM Data s
JOIN Data e
ON e.x > s.x
) data
WHERE data.y_delta > @yDelta AND data.x_delta BETWEEN @xFrom AND @xTo
答案 1 :(得分：1)
主要问题是where子句给出了一个交叉连接（不是我所说的简单连接）（给出很多行是连接比较e中的一行中的很多行）和.y比较必须使用表扫描（至少临时数据，如果不是整个表）。
如果查询很常见，那么可以修复连接一次并将数据复制到预先计算的表中并将差异编入索引。
答案 2 :(得分：1)
我可以想到一个提高性能的奇怪策略。这包括在表中添加一个自动递增的id，然后根据id查找Xfrom和Xto的边界，然后查找范围内的任何内容。
以下查询表明了我的意思：
with e1 as (
select e.*,
(select min(id) from data s where e.x between s.x + @xfrom and s.x + @xto) as idstart,
(select max(id) from data s where e.x between s.x + @xfrom and s.x + @xto) as idend
from data e
)
select <whatever>
from e1 join
e1 s
on e1.idstart = s.id
where e1.idstart <= e1.idend union all
select <whatever>
from e1 join
e1 s
on e1.idstart+1 = s.id
where e1.idstart+1 <= e1.idend
. . .
我对索引字段上的相关子查询返回下一个值有好运。之后，连接是equijoins，应该非常快。最后，您可能希望修改查询，以便它可以使用枚举值表进行比较。