3
LLBLでいくつかの低速プリフェッチクエリを処理しています。ここで生成されたSQLの簡易版です：サブクエリIN節が低速ですか？
SELECT DISTINCT
Column1
FROM
Table1
WHERE
Table1.Table2ID IN
(
SELECT Table2.Table2ID AS Table2ID
FROM
Table2
INNER JOIN Table1 ON Table2.Table2ID=Table1.Table2ID
INNER JOIN
(
SELECT DISTINCT
Table1.Table2ID AS Table2ID,
MAX(Table1.EffectiveDate) AS EffectiveDate
FROM Table1
WHERE Table1.EffectiveDate <= '2012-01-03 00:00:00:000'
GROUP BY Table1.Table2ID
) MaxEffective
ON
MaxEffective.Table2ID = Table1.Table2ID
AND MaxEffective.EffectiveDate = Table1.EffectiveDate
)
私は何を見つけることだが、サブクエリが速く実行していることであると私は、実際の結果とそのサブクエリを交換する場合は、外側のクエリが高速です。しかし、一緒に、彼らは遅いです。
少し助けてくれたデータベースエンジンチューニングアドバイザーを実行しましたが、まだかなり遅いです。
私は、実行計画を理解する上で非常に熟練していないんだけど、時間の大部分は、インデックス表1に追求に費やされる表示されます。
これは、相関のないサブクエリであるため、これをより高速に実行することが期待されていました。私が見ていないことはありますか？
もしそれがまっすぐなSQLだったら、クエリを書き換えて結合しますが、私はかなりLLBLに固執しています。参加を強制するために使用できる設定はありますか？ SQL Serverが結合の場合と同じ実行計画を生成しない理由はありますか？
実際のクエリの編集...
SELECT DISTINCT
ResidentialComponentValues.ResidentialComponentValueID AS ResidentialComponentValueId,
ResidentialComponentValues.ResidentialComponentTypeID AS ResidentialComponentTypeId,
ResidentialComponentValues.Value,
ResidentialComponentValues.Story,
ResidentialComponentValues.LastUpdated,
ResidentialComponentValues.LastUpdatedBy,
ResidentialComponentValues.ConcurrencyTimestamp,
ResidentialComponentValues.EffectiveDate,
ResidentialComponentValues.DefaultQuantity
FROM
ResidentialComponentValues
WHERE
ResidentialComponentValues.ResidentialComponentTypeID IN
(
SELECT ResidentialComponentTypes.ResidentialComponentTypeID AS ResidentialComponentTypeId
FROM
ResidentialComponentTypes INNER JOIN ResidentialComponentValues
ON ResidentialComponentTypes.ResidentialComponentTypeID=ResidentialComponentValues.ResidentialComponentTypeID
INNER JOIN
(
SELECT DISTINCT
ResidentialComponentValues.ResidentialComponentTypeID AS ResidentialComponentTypeId,
MAX(ResidentialComponentValues.EffectiveDate) AS EffectiveDate
FROM ResidentialComponentValues
WHERE ResidentialComponentValues.EffectiveDate <= '2012-01-03 00:00:00:000'
GROUP BY ResidentialComponentValues.ResidentialComponentTypeID
) LPA_E1
ON
LPA_E1.ResidentialComponentTypeId = ResidentialComponentValues.ResidentialComponentTypeID
AND LPA_E1.EffectiveDate = ResidentialComponentValues.EffectiveDate
)
文を作成するための編集：
/****** Object: Table [dbo].[ResidentialComponentTypes] Script Date: 01/03/2012 13:49:06 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[ResidentialComponentTypes](
[ResidentialComponentTypeID] [int] IDENTITY(1,1) NOT NULL,
[ComponentTypeName] [varchar](255) NOT NULL,
[LastUpdated] [datetime] NOT NULL,
[LastUpdatedBy] [varchar](50) NOT NULL,
[ConcurrencyTimestamp] [timestamp] NOT NULL,
[Active] [bit] NOT NULL,
CONSTRAINT [PK_ResidentialComponentTypes] PRIMARY KEY CLUSTERED
(
[ResidentialComponentTypeID] 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
SET ANSI_PADDING OFF
GO
/****** Object: Table [dbo].[ResidentialComponentValues] Script Date: 01/03/2012 13:49:06 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[ResidentialComponentValues](
[ResidentialComponentValueID] [int] IDENTITY(1,1) NOT NULL,
[ResidentialComponentTypeID] [int] NOT NULL,
[Value] [decimal](18, 3) NOT NULL,
[Story] [varchar](255) NOT NULL,
[LastUpdated] [datetime] NOT NULL,
[LastUpdatedBy] [varchar](50) NOT NULL,
[ConcurrencyTimestamp] [timestamp] NOT NULL,
[EffectiveDate] [datetime] NOT NULL,
[DefaultQuantity] [int] NOT NULL,
CONSTRAINT [PK_ResidentialComponentPrices] PRIMARY KEY CLUSTERED
(
[ResidentialComponentValueID] 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
SET ANSI_PADDING OFF
GO
CREATE NONCLUSTERED INDEX [_dta_index_ResidentialComponentValues_71_56543435__K1] ON [dbo].[ResidentialComponentValues]
(
[ResidentialComponentValueID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
CREATE NONCLUSTERED INDEX [_dta_index_ResidentialComponentValues_71_56543435__K1_2_3_4_5_6_7_8_9] ON [dbo].[ResidentialComponentValues]
(
[ResidentialComponentValueID] ASC
)
INCLUDE ([ResidentialComponentTypeID],
[Value],
[Story],
[LastUpdated],
[LastUpdatedBy],
[ConcurrencyTimestamp],
[EffectiveDate],
[DefaultQuantity]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
CREATE NONCLUSTERED INDEX [_dta_index_ResidentialComponentValues_71_56543435__K2_K1] ON [dbo].[ResidentialComponentValues]
(
[ResidentialComponentTypeID] ASC,
[ResidentialComponentValueID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
CREATE NONCLUSTERED INDEX [_dta_index_ResidentialComponentValues_71_56543435__K2_K8_K1] ON [dbo].[ResidentialComponentValues]
(
[ResidentialComponentTypeID] ASC,
[EffectiveDate] ASC,
[ResidentialComponentValueID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
CREATE NONCLUSTERED INDEX [_dta_index_ResidentialComponentValues_71_56543435__K2_K8_K1_3_4_5_6_7_9] ON [dbo].[ResidentialComponentValues]
(
[ResidentialComponentTypeID] ASC,
[EffectiveDate] ASC,
[ResidentialComponentValueID] ASC
)
INCLUDE ([Value],
[Story],
[LastUpdated],
[LastUpdatedBy],
[ConcurrencyTimestamp],
[DefaultQuantity]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object: ForeignKey [FK_ResidentialComponentValues_ResidentialComponentTypes] Script Date: 01/03/2012 13:49:06 ******/
ALTER TABLE [dbo].[ResidentialComponentValues] WITH CHECK ADD CONSTRAINT [FK_ResidentialComponentValues_ResidentialComponentTypes] FOREIGN KEY([ResidentialComponentTypeID])
REFERENCES [dbo].[ResidentialComponentTypes] ([ResidentialComponentTypeID])
GO
ALTER TABLE [dbo].[ResidentialComponentValues] CHECK CONSTRAINT [FK_ResidentialComponentValues_ResidentialComponentTypes]
GO
を返します。これは単純化されていますが、内部クエリと外部クエリの間に重複エイリアスが存在する可能性があります。そうした場合、エンジンは相関サブクエリとしてこれを実行しようとしている可能性があります。これははるかに遅くなる可能性があります。 – JNK
エイリアスはありませんが、テーブル名を直接参照することでも同じことが行われます。サブクエリ内のTable1にエイリアスを追加してみましょう。 – Dan
@JNK - これは* scope *のすべての規則を破りますが、これは本当に問題だとは思いません。 – MatBailie