J'ai une table SQL Server définie comme suit
CREATE TABLE [dbo].[Production_Detail]
(
[Id] [bigint] NOT NULL DEFAULT (NEXT VALUE FOR [dbo].[Production_Detail_Seq]),
[Meta_Data_ID] INT NOT NULL ,
[Production_Detail_Time] DATETIME NOT NULL,
[Production_Detail_Time_Local] DATETIME NOT NULL,
[Production_Detail_Value] FLOAT NULL,
[IntegratedDM] BIT NOT NULL DEFAULT 0,
[DailyIntegratedDM] BIT NOT NULL DEFAULT 0,
[InsertedDate] DateTime NOT NULL,
[ModifiedDate] DateTime NOT NULL,
CONSTRAINT [PK_Production_Detail] PRIMARY KEY ([Id]),
CONSTRAINT [UK_Production_Detail] UNIQUE ([Meta_Data_Id], [Production_Detail_Time]),
CONSTRAINT [FK_Production_Detail_To_Meta_Data] FOREIGN KEY ([Meta_Data_ID]) REFERENCES [Meta_Data]([Meta_Data_ID])
)
GO
CREATE NONCLUSTERED INDEX [IX_Production_Detail_Production_Detail_Time_Local]
ON [dbo].[Production_Detail] ([Production_Detail_Time_Local])
INCLUDE ([Meta_Data_ID], [Production_Detail_Time], [Production_Detail_Value])
GO
CREATE UNIQUE NONCLUSTERED INDEX [IX_Production_Detail_Meta_Data_ID_Production_Detail_Time]
ON [dbo].[Production_Detail] ([Meta_Data_ID] ASC, [Production_Detail_Time] ASC)
GO
CREATE NONCLUSTERED INDEX [IX_Production_Detail_IntegratedDM_MetaDataId]
ON [dbo].[Production_Detail] ([IntegratedDM], [Meta_Data_ID])
INCLUDE ([Production_Detail_Time])
GO
Ce tableau contient des données en temps réel, de sorte que les enregistrements sont insérés de manière cohérente. J'essaie de supprimer des données datant de plus de 5 jours. Mais lorsque la suppression est en cours d'exécution, j'ai plusieurs instructions d'insertion qui jettent un blocage.
Voici la requête de suppression. Le #ToPurge
tableau contient l'ID qui doit être supprimé. La #ToPurge
table n'a pas d'index. Le nombre de lignes peut varier, mais pour mon cas de test, il y en avait plus de 3 millions:
Declare @RowCount int;
set @RowCount = @@ROWCOUNT;
while @RowCount > 0
begin
delete top(20000) pd
from #ToPurge tp
inner join [DataWarehouse].[dbo].[Production_Detail] pd on (tp.ID = pd.ID)
set @RowCount = @@ROWCOUNT;
end
Voici le plan d'exécution de la requête de suppression
<?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="11.0.3128.0" xmlns="http://schemas.microsoft.com/sqlserver/2004/07/showplan">
<BatchSequence>
<Batch>
<Statements>
<StmtSimple StatementCompId="1" StatementEstRows="20000" StatementId="1" StatementOptmLevel="FULL" StatementSubTreeCost="34.7996" StatementText=" delete top(20000) pd
 from #ToPurge tp
 inner join [DataWarehouse].[dbo].[Production_Detail] pd on (tp.ID = pd.ID)" StatementType="DELETE" QueryHash="0xF7A9CF8E140CDB4E" QueryPlanHash="0x2CC61A780737A398" RetrievedFromCache="false">
<StatementSetOptions ANSI_NULLS="true" ANSI_PADDING="true" ANSI_WARNINGS="true" ARITHABORT="true" CONCAT_NULL_YIELDS_NULL="true" NUMERIC_ROUNDABORT="false" QUOTED_IDENTIFIER="true" />
<QueryPlan CachedPlanSize="88" CompileTime="65" CompileCPU="65" CompileMemory="592">
<ThreadStat Branches="2" />
<MemoryGrantInfo SerialRequiredMemory="1024" SerialDesiredMemory="477448" />
<OptimizerHardwareDependentProperties EstimatedAvailableMemoryGrant="209715" EstimatedPagesCached="419430" EstimatedAvailableDegreeOfParallelism="4" />
<RelOp AvgRowSize="9" EstimateCPU="0.08" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Sequence" NodeId="0" Parallel="false" PhysicalOp="Sequence" EstimatedTotalSubtreeCost="34.7996">
<OutputList />
<Sequence>
<RelOp AvgRowSize="9" EstimateCPU="0.02" EstimateIO="0.458155" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Delete" NodeId="1" Parallel="false" PhysicalOp="Index Delete" EstimatedTotalSubtreeCost="8.56272">
<OutputList />
<Update WithUnorderedPrefetch="true" DMLRequestSort="false">
<Object Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Index="[UK_Production_Detail]" Alias="[pd]" IndexKind="NonClustered" />
<RelOp AvgRowSize="36" EstimateCPU="0.00182568" EstimateIO="0.00328238" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Eager Spool" NodeId="3" Parallel="false" PhysicalOp="Table Spool" EstimatedTotalSubtreeCost="8.08456">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Meta_Data_ID" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time_Local" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="IntegratedDM" />
</OutputList>
<Spool>
<RelOp AvgRowSize="36" EstimateCPU="0.02" EstimateIO="1.31642" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Delete" NodeId="4" Parallel="false" PhysicalOp="Clustered Index Delete" EstimatedTotalSubtreeCost="32.3067">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Meta_Data_ID" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time_Local" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="IntegratedDM" />
</OutputList>
<Update WithUnorderedPrefetch="true" DMLRequestSort="false">
<Object Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Index="[PK_Production_Detail]" Alias="[pd]" IndexKind="Clustered" />
<RelOp AvgRowSize="15" EstimateCPU="0.002" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Top" NodeId="6" Parallel="false" PhysicalOp="Top" EstimatedTotalSubtreeCost="30.9703">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</OutputList>
<Top RowCount="false" IsPercent="false" WithTies="false">
<TopExpression>
<ScalarOperator ScalarString="(20000)">
<Const ConstValue="(20000)" />
</ScalarOperator>
</TopExpression>
<RelOp AvgRowSize="15" EstimateCPU="0.0392491" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Gather Streams" NodeId="7" Parallel="true" PhysicalOp="Parallelism" EstimatedTotalSubtreeCost="30.9683">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</OutputList>
<Parallelism>
<RelOp AvgRowSize="15" EstimateCPU="276.841" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Right Semi Join" NodeId="8" Parallel="true" PhysicalOp="Hash Match" EstimatedTotalSubtreeCost="30.929">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</OutputList>
<MemoryFractions Input="1" Output="1" />
<Hash>
<DefinedValues />
<HashKeysBuild>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</HashKeysBuild>
<HashKeysProbe>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</HashKeysProbe>
<ProbeResidual>
<ScalarOperator ScalarString="[DataWarehouse].[dbo].[Production_Detail].[Id] as [pd].[Id]=[tempdb].[dbo].[#ToPurge].[Id] as [tp].[Id]">
<Compare CompareOp="EQ">
<ScalarOperator>
<Identifier>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</Identifier>
</ScalarOperator>
</Compare>
</ScalarOperator>
</ProbeResidual>
<RelOp AvgRowSize="15" EstimateCPU="2.83429" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="3910180" LogicalOp="Bitmap Create" NodeId="9" Parallel="true" PhysicalOp="Bitmap" EstimatedTotalSubtreeCost="9.99726">
<OutputList>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</OutputList>
<Bitmap>
<DefinedValues>
<DefinedValue>
<ColumnReference Column="Bitmap1007" />
</DefinedValue>
</DefinedValues>
<HashKeys>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</HashKeys>
<RelOp AvgRowSize="15" EstimateCPU="2.83429" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="3910180" LogicalOp="Repartition Streams" NodeId="10" Parallel="true" PhysicalOp="Parallelism" EstimatedTotalSubtreeCost="9.99726">
<OutputList>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</OutputList>
<Parallelism PartitioningType="Hash">
<PartitionColumns>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</PartitionColumns>
<RelOp AvgRowSize="15" EstimateCPU="1.07532" EstimateIO="6.08765" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="3910180" LogicalOp="Table Scan" NodeId="11" Parallel="true" PhysicalOp="Table Scan" EstimatedTotalSubtreeCost="7.16297" TableCardinality="3910180">
<OutputList>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</OutputList>
<TableScan Ordered="false" ForcedIndex="false" ForceScan="false" NoExpandHint="false">
<DefinedValues>
<DefinedValue>
<ColumnReference Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" Column="Id" />
</DefinedValue>
</DefinedValues>
<Object Database="[tempdb]" Schema="[dbo]" Table="[#ToPurge]" Alias="[tp]" IndexKind="Heap" />
</TableScan>
</RelOp>
</Parallelism>
</RelOp>
</Bitmap>
</RelOp>
<RelOp AvgRowSize="15" EstimateCPU="0.675882" EstimateIO="0" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="902193" LogicalOp="Repartition Streams" NodeId="12" Parallel="true" PhysicalOp="Parallelism" EstimatedTotalSubtreeCost="3.17684">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</OutputList>
<Parallelism PartitioningType="Hash">
<PartitionColumns>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</PartitionColumns>
<RelOp AvgRowSize="15" EstimateCPU="43.216" EstimateIO="391.867" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="902193" LogicalOp="Index Scan" NodeId="13" Parallel="true" PhysicalOp="Index Scan" EstimatedTotalSubtreeCost="2.50096" TableCardinality="157149000">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</OutputList>
<IndexScan Ordered="true" ScanDirection="FORWARD" ForcedIndex="false" ForceSeek="false" ForceScan="false" NoExpandHint="false" Storage="RowStore">
<DefinedValues>
<DefinedValue>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</DefinedValue>
</DefinedValues>
<Object Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Index="[UK_Production_Detail]" Alias="[pd]" IndexKind="NonClustered" />
<Predicate>
<ScalarOperator ScalarString="PROBE([Bitmap1007],[DataWarehouse].[dbo].[Production_Detail].[Id] as [pd].[Id],N'[IN ROW]')">
<Intrinsic FunctionName="PROBE">
<ScalarOperator>
<Identifier>
<ColumnReference Column="Bitmap1007" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Identifier>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
</Identifier>
</ScalarOperator>
<ScalarOperator>
<Const ConstValue="N'[IN ROW]'" />
</ScalarOperator>
</Intrinsic>
</ScalarOperator>
</Predicate>
</IndexScan>
</RelOp>
</Parallelism>
</RelOp>
</Hash>
</RelOp>
</Parallelism>
</RelOp>
</Top>
</RelOp>
</Update>
</RelOp>
</Spool>
</RelOp>
</Update>
</RelOp>
<RelOp AvgRowSize="9" EstimateCPU="0.02" EstimateIO="0.906841" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Delete" NodeId="16" Parallel="false" PhysicalOp="Index Delete" EstimatedTotalSubtreeCost="9.0114">
<OutputList />
<Update WithUnorderedPrefetch="true" DMLRequestSort="false">
<Object Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Index="[IX_Production_Detail_Production_Detail_Time_Local]" Alias="[pd]" IndexKind="NonClustered" />
<RelOp AvgRowSize="36" EstimateCPU="0.00182568" EstimateIO="0.00328238" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Eager Spool" NodeId="18" Parallel="false" PhysicalOp="Table Spool" EstimatedTotalSubtreeCost="8.08456">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Meta_Data_ID" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time_Local" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="IntegratedDM" />
</OutputList>
<Spool PrimaryNodeId="3" />
</RelOp>
</Update>
</RelOp>
<RelOp AvgRowSize="9" EstimateCPU="0.02" EstimateIO="0.458164" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Delete" NodeId="19" Parallel="false" PhysicalOp="Index Delete" EstimatedTotalSubtreeCost="8.56272">
<OutputList />
<Update WithUnorderedPrefetch="true" DMLRequestSort="false">
<Object Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Index="[IX_Production_Detail_Meta_Data_ID_Production_Detail_Time]" Alias="[pd]" IndexKind="NonClustered" />
<RelOp AvgRowSize="36" EstimateCPU="0.00182568" EstimateIO="0.00328238" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Eager Spool" NodeId="21" Parallel="false" PhysicalOp="Table Spool" EstimatedTotalSubtreeCost="8.08456">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Meta_Data_ID" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time_Local" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="IntegratedDM" />
</OutputList>
<Spool PrimaryNodeId="3" />
</RelOp>
</Update>
</RelOp>
<RelOp AvgRowSize="9" EstimateCPU="0.02" EstimateIO="0.478182" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Delete" NodeId="22" Parallel="false" PhysicalOp="Index Delete" EstimatedTotalSubtreeCost="8.58274">
<OutputList />
<Update WithUnorderedPrefetch="true" DMLRequestSort="false">
<Object Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Index="[IX_Production_Detail_IntegratedDM_MetaDataId]" Alias="[pd]" IndexKind="NonClustered" />
<RelOp AvgRowSize="36" EstimateCPU="0.00182568" EstimateIO="0.00328238" EstimateRebinds="0" EstimateRewinds="0" EstimatedExecutionMode="Row" EstimateRows="20000" LogicalOp="Eager Spool" NodeId="24" Parallel="false" PhysicalOp="Table Spool" EstimatedTotalSubtreeCost="8.08456">
<OutputList>
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Id" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Meta_Data_ID" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="Production_Detail_Time_Local" />
<ColumnReference Database="[DataWarehouse]" Schema="[dbo]" Table="[Production_Detail]" Alias="[pd]" Column="IntegratedDM" />
</OutputList>
<Spool PrimaryNodeId="3" />
</RelOp>
</Update>
</RelOp>
</Sequence>
</RelOp>
</QueryPlan>
</StmtSimple>
</Statements>
</Batch>
</BatchSequence>
</ShowPlanXML>
Comme vous pouvez le voir dans le plan d'exécution, l'optimiseur n'utilise pas l'index cluster du primaire, mais utilise à la place la clé Unique qui ne contient pas le champ Id. Je pense que c'est la raison pour laquelle j'ai un blocage car il doit verrouiller plus de page que s'il utilisait le bon index.
J'essaie d'ajouter un index non cluster avec l'ID et ensuite l'optimiseur l'utilise.
CREATE UNIQUE NONCLUSTERED INDEX [NonClusteredIndex-20160617-104555]
ON [dbo].[Production_Detail] ([Id] ASC)
GO
Je voudrais savoir pourquoi l'optimiseur n'utilise pas l'index clusterisé, mais utilise celui non clusterisé?