Partition Table

what is Partition Table?

Looking to optimize the performance of your SQL Server database? If your database contains very large tables, you may benefit from partitioning those tables onto separate filegroups. Allows you to spread data onto different physical disks, leveraging the concurrent performance of those disks to optimize query performance.

Partitioning a SQL Server database table is a three-step process:

1. Create the partition function

    CREATE PARTITION FUNCTION customer_partfunc (int)

    AS RANGE RIGHT

    FOR VALUES (250000, 500000, 750000)

2. Create the partition scheme

    CREATE PARTITION SCHEME customer_partscheme

    AS PARTITION customer_partfunc

    TO (fg1, fg2, fg3, fg4)

3. Partition the table

    CREATE TABLE customers (FirstName nvarchar(40), LastName nvarchar(40), CustomerNumber int)

    ON customer_partscheme (CustomerNumber)

Creates a scheme in the current database that maps the partitions of a partitioned table or index to filegroups. The number and domain of the partitions of a partitioned table or index are determined in a partition function. A partition function must first be created in a CREATE PARTITION FUNCTION statement before creating a partition scheme.

CREATE PARTITION SCHEME partition_scheme_name

AS PARTITION partition_function_name

[ ALL ] TO ( { file_group_name | [ PRIMARY ] } [ ,...n ] )

[ ; ]

 

The following example creates a partition function to partition a table or index into four partitions. A partition scheme is then created that specifies the filegroups to hold each one of the four partitions. This example assumes the filegroups already exist in the database.

CREATE PARTITION FUNCTION myRangePF1 (int)

AS RANGE LEFT FOR VALUES (1, 100, 1000);

GO

CREATE PARTITION SCHEME myRangePS1

AS PARTITION myRangePF1

TO (test1fg, test2fg, test3fg, test4fg);

The partitions of a table that uses partition function myRangePF1 on partitioning column col1 would be assigned as shown in the following table.

Filegroup	test1fg	test2fg	test3fg	test4fg
Partition	1	2	3	4
Values	col1 <= 1	col1 > 1 AND col1 <= 100	col1 > 100 AND col1 <= 1000	col1 > 1000

 

 

 

 

来自为知笔记(Wiz)