分区现有表

Question

我有一个 800 GB 的表，我需要按年对其进行分区

这是当前的表

CREATE TABLE [dbo].[MessageInbox]
(
    [Id] [INT] IDENTITY(1, 1) NOT FOR REPLICATION NOT NULL,
    [Subject] [VARCHAR](250) NULL,
    [MessageFrom] [VARCHAR](50) NULL,
    [MessageText] [VARCHAR](MAX) NULL,
    [DateReceived] [DATETIME] NOT NULL,
    [DateCreated] [DATETIME] NOT NULL,
    [ProfileId] [INT] NOT NULL,
    [IsRead] [BIT] NULL,
    [InstanceId] [INT] NULL,
    [msgType] [VARCHAR](25) NULL,
    [Tags] [VARCHAR](100) NULL,
    [excerpt] [VARCHAR](500) NULL,
    CONSTRAINT [PK_Inbox]
        PRIMARY KEY CLUSTERED ([Id] ASC)
        WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON,
              ALLOW_PAGE_LOCKS = ON
             ) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY];
GO

这就是我在分区时的方式

CREATE PARTITION FUNCTION [PartitioningByYear] (DATETIME)
AS RANGE RIGHT FOR VALUES
(   '20150101',
    '20160101',
    '20170101',
    '20180101',
    '20190101',
    '20200101',
    '20210101',
    '20220101',
    '20230101',
    '20240101'
);


---DROP PARTITION FUNCTION [PartitioningByYear];
CREATE PARTITION SCHEME PartitionByYear
AS PARTITION PartitioningByYear
TO
(
    Year2014,
    Year2015,
    Year2016,
    Year2017,
    Year2018,
    Year2019,
    Year2020,
    Year2021,
    Year2022,
    Year2023,
    Year2024
);


CREATE TABLE [dbo].[MessageInbox]
(
    [Id] [INT] IDENTITY(1, 1) NOT FOR REPLICATION NOT NULL,
    [Subject] [VARCHAR](250) NULL,
    [MessageFrom] [VARCHAR](50) NULL,
    [MessageText] [VARCHAR](MAX) NULL,
    [DateReceived] [DATETIME] NOT NULL,
    [DateCreated] [DATETIME] NOT NULL,
    [ProfileId] [INT] NOT NULL,
    [IsRead] [BIT] NULL,
    [InstanceId] [INT] NULL,
    [msgType] [VARCHAR](25) NULL,
    [Tags] [VARCHAR](100) NULL,
    [excerpt] [VARCHAR](500) NULL
) ON PartitionByYear (DateCreated);

CREATE CLUSTERED INDEX CI_MessageInbox1
ON dbo.MessageInbox (DateCreated);
GO
CREATE NONCLUSTERED INDEX IX_messageinbox_id ON dbo.MessageInbox (Id);

我的问题是

1- 这是创建分区表的最佳方式吗？

2- 我对没有将 ID 作为主键感到困惑，有没有办法将它添加到主键？

3- 将日期创建为聚集索引中的键。这不是会降低性能并为每个查询添加额外的键查找吗？

我想对表进行分区，因为如果我需要存档/删除旧的年份会更容易。而且我可以在分区上创建索引/维护，而不是在整个表上创建一个索引。

Answer 1

主键不需要与集群键相同。创建主键时的默认设置也是使其成为聚集索引，但这不是必需的。

试试这个CREATE TABLE语句：

CREATE TABLE [dbo].[MessageInbox]
(
    [Id] [INT] NOT NULL
        IDENTITY(1, 1)
        NOT FOR REPLICATION
        PRIMARY KEY NONCLUSTERED,
    [Subject] [VARCHAR](250) NULL,
    [MessageFrom] [VARCHAR](50) NULL,
    [MessageText] [VARCHAR](MAX) NULL,
    [DateReceived] [DATETIME] NOT NULL,
    [DateCreated] [DATETIME] NOT NULL
        INDEX MessageInbox_cx CLUSTERED,
    [ProfileId] [INT] NOT NULL,
    [IsRead] [BIT] NULL,
    [InstanceId] [INT] NULL,
    [msgType] [VARCHAR](25) NULL,
    [Tags] [VARCHAR](100) NULL,
    [excerpt] [VARCHAR](500) NULL
) ON PartitionByYear (DateCreated);

这将使该[id]列成为主键，而该[DateCreated]列将成为聚集索引。

在不太了解您的数据的情况下，我会说将数据压缩添加到您的表和非聚集索引可能会有所帮助。您可以通过在CREATE TABLE语句中添加以下内容来实现：

CREATE TABLE [dbo].[MessageInbox]
(
    [Id] [INT] NOT NULL
        IDENTITY(1, 1)
        NOT FOR REPLICATION
        PRIMARY KEY NONCLUSTERED
        WITH (DATA_COMPRESSION = PAGE),
    [Subject] [VARCHAR](250) NULL,
    [MessageFrom] [VARCHAR](50) NULL,
    [MessageText] [VARCHAR](MAX) NULL,
    [DateReceived] [DATETIME] NOT NULL,
    [DateCreated] [DATETIME] NOT NULL
        INDEX MessageInbox_cx CLUSTERED
        WITH (DATA_COMPRESSION = PAGE),
    [ProfileId] [INT] NOT NULL,
    [IsRead] [BIT] NULL,
    [InstanceId] [INT] NULL,
    [msgType] [VARCHAR](25) NULL,
    [Tags] [VARCHAR](100) NULL,
    [excerpt] [VARCHAR](500) NULL
) ON PartitionByYear (DateCreated);