Yürütme planı için showplan.xsd'ye göre, bu GroupBy
olmadan görünür minOccurs
veya maxOccurs
bu nedenle [1..1] öğesinin zorunlu olması, içeriği zorunlu olarak zorunlu kılma özniteliklerine sahip değildir. ColumnReference
( ColumnReferenceType
) Türünün alt öğesinin minOccurs
0 değeri vardır ve maxOccurs
sınırsız [0 .. *] vardır, bu da onu isteğe bağlı yapar , bu nedenle izin verilen boş öğedir. GroupBy
Planı el ile kaldırmaya ve zorlamaya çalışırsanız beklenen hatayı alırsınız:
Msg 6965, Level 16, State 1, Line 29
XML Validation: Invalid content. Expected element(s): '{http://schemas.microsoft.com/sqlserver/2004/07/showplan}GroupBy','{http://schemas.microsoft.com/sqlserver/2004/07/showplan}DefinedValues','{http://schemas.microsoft.com/sqlserver/2004/07/showplan}InternalInfo'. Found: element '{http://schemas.microsoft.com/sqlserver/2004/07/showplan}SegmentColumn' instead. Location: /*:ShowPlanXML[1]/*:BatchSequence[1]/*:Batch[1]/*:Statements[1]/*:StmtSimple[1]/*:QueryPlan[1]/*:RelOp[1]/*:SequenceProject[1]/*:RelOp[1]/*:Segment[1]/*:SegmentColumn[1].
İlginç bir şekilde, Segment operatörünü, şunun gibi görünen geçerli bir plan almak için manuel olarak kaldırabileceğinizi buldum:
Ancak bu planla (kullanarak OPTION ( USE PLAN ... )
) çalıştırdığınızda , Segment Operatörü sihirli bir şekilde yeniden görünür. Sadece optimize edicinin sadece kaba bir kılavuz olarak XML planlarını aldığını göstermeye gider.
Test donanımım:
USE tempdb
GO
SET NOCOUNT ON
GO
IF OBJECT_ID('dbo.someTable') IS NOT NULL DROP TABLE dbo.someTable
GO
CREATE TABLE dbo.someTable (
someGroup int NOT NULL,
someOrder int NOT NULL,
someValue numeric(8, 2) NOT NULL,
PRIMARY KEY CLUSTERED (someGroup, someOrder)
);
GO
-- Generate some dummy data
;WITH cte AS (
SELECT TOP 1000 ROW_NUMBER() OVER ( ORDER BY ( SELECT 1 ) ) rn
FROM master.sys.columns c1
CROSS JOIN master.sys.columns c2
CROSS JOIN master.sys.columns c3
)
INSERT INTO dbo.someTable ( someGroup, someOrder, someValue )
SELECT rn % 333, rn % 444, rn % 55
FROM cte
GO
-- Try and force the plan
SELECT ROW_NUMBER() OVER (ORDER BY someGroup, someOrder)
FROM dbo.someTable
OPTION ( USE PLAN N'<?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="12.0.2000.8" xmlns="http://schemas.microsoft.com/sqlserver/2004/07/showplan">
<BatchSequence>
<Batch>
<Statements>
<StmtSimple StatementCompId="1" StatementEstRows="1000" StatementId="1" StatementOptmLevel="TRIVIAL" CardinalityEstimationModelVersion="120" StatementSubTreeCost="0.00596348" StatementText="SELECT ROW_NUMBER() OVER (ORDER BY someGroup, someOrder)
FROM dbo.someTable" StatementType="SELECT" QueryHash="0x193176312402B8E7" QueryPlanHash="0x77F1D72C455025A4" 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="1" CachedPlanSize="16" CompileTime="0" CompileCPU="0" CompileMemory="88">
<OptimizerHardwareDependentProperties EstimatedAvailableMemoryGrant="131072" EstimatedPagesCached="65536" EstimatedAvailableDegreeOfParallelism="4" />
<RelOp AvgRowSize="15" EstimateCPU="8E-05" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="1000" LogicalOp="Compute Scalar" NodeId="0" Parallel="false" PhysicalOp="Sequence Project" EstimatedTotalSubtreeCost="0.00596348">
<OutputList>
<ColumnReference Column="Expr1002" />
</OutputList>
<SequenceProject>
<DefinedValues>
<DefinedValue>
<ColumnReference Column="Expr1002" />
<ScalarOperator ScalarString="row_number">
<Sequence FunctionName="row_number" />
</ScalarOperator>
</DefinedValue>
</DefinedValues>
<!-- Segment operator completely removed from plan -->
<!--<RelOp AvgRowSize="15" EstimateCPU="2E-05" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="1000" LogicalOp="Segment" NodeId="1" Parallel="false" PhysicalOp="Segment" EstimatedTotalSubtreeCost="0.00588348">
<OutputList>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[someTable]" Column="someGroup" />
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[someTable]" Column="someOrder" />
<ColumnReference Column="Segment1003" />
</OutputList>
<Segment>
<GroupBy />
<SegmentColumn>
<ColumnReference Column="Segment1003" />
</SegmentColumn>-->
<RelOp AvgRowSize="15" EstimateCPU="0.001257" EstimateIO="0.00460648" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="1000" LogicalOp="Clustered Index Scan" NodeId="0" Parallel="false" PhysicalOp="Clustered Index Scan" EstimatedTotalSubtreeCost="0.00586348" TableCardinality="1000">
<OutputList>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[someTable]" Column="someGroup" />
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[someTable]" Column="someOrder" />
</OutputList>
<IndexScan Ordered="true" ScanDirection="FORWARD" ForcedIndex="false" ForceSeek="false" ForceScan="false" NoExpandHint="false" Storage="RowStore">
<DefinedValues>
<DefinedValue>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[someTable]" Column="someGroup" />
</DefinedValue>
<DefinedValue>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[someTable]" Column="someOrder" />
</DefinedValue>
</DefinedValues>
<Object Database="[tempdb]" Schema="[dbo]" Table="[someTable]" Index="[PK__someTabl__7CD03C8950FF62C1]" IndexKind="Clustered" Storage="RowStore" />
</IndexScan>
</RelOp>
<!--</Segment>
</RelOp>-->
</SequenceProject>
</RelOp>
</QueryPlan>
</StmtSimple>
</Statements>
</Batch>
</BatchSequence>
</ShowPlanXML>' )
Test planından XML planını kesin ve planı eksi Segmenti görüntülemek için .sqlplan olarak kaydedin.
PS Ben SQL planları etrafında doğrama gibi çok fazla zaman harcamak olmaz gibi beni bilir gibi zaman yeme meşgul çalışma ve asla yapmak bir şey olarak kabul biliyorum. Bekle !? :)