用于分区 Memory-Optimized 表的应用程序模式

2017-06-13

In-Memory OLTP 支持一种模式，即在内存优化表中保留有限的活动数据，而在磁盘上处理频率较低的数据。通常，这是一种基于 datetime 密钥存储数据的场景。

可以通过维护一个具有通用架构的已分区表和一个内存优化表来模拟已分区表。在内存优化表中插入和更新当前数据，而不太频繁访问的数据将保留在传统的分区表中。

知道活动数据位于内存优化表中的应用程序可以使用本机编译的存储过程来访问数据。需要访问整个数据范围的操作，或者可能不知道哪个表包含相关数据，请使用解释的 Transact-SQL 来将内存优化表与分区表联接。

此分区开关如下所述：

将数据从 In-Memory OLTP 表插入到一个暂存表中，可能需要使用截止日期。
从内存优化表中删除相同的数据。
在暂存表中交换。
添加活动分区。

分区开关。
主动数据维护

从删除 ActiveOrders 开始的操作需要在维护时段内进行，以避免在删除数据和在暂存表中切换期间查询缺失数据。

有关相关示例，请参阅 Application-Level 分区。

代码示例

以下示例演示如何将内存优化表与基于磁盘的分区表配合使用。常用数据存储在内存中。若要将数据保存到磁盘，请创建新分区并将数据复制到分区表。

此示例的第一部分创建数据库和必要的对象。示例的第二部分演示如何将数据从内存优化表移到分区表中。

CREATE DATABASE partitionsample;  
GO  
  
-- enable for In-Memory OLTP - change file path as needed  
ALTER DATABASE partitionsample ADD FILEGROUP partitionsample_mod CONTAINS MEMORY_OPTIMIZED_DATA  
ALTER DATABASE partitionsample ADD FILE( NAME = 'partitionsample_mod' , FILENAME = 'c:\data\partitionsample_mod') TO FILEGROUP partitionsample_mod;  
GO  
  
USE partitionsample;  
GO  
  
-- frequently used portion of the SalesOrders - memory-optimized  
  
CREATE TABLE dbo.SalesOrders_hot (  
   so_id INT IDENTITY PRIMARY KEY NONCLUSTERED,  
   cust_id INT NOT NULL,  
   so_date DATETIME2 NOT NULL INDEX ix_date NONCLUSTERED,  
   so_total MONEY NOT NULL,  
   INDEX ix_date_total NONCLUSTERED (so_date desc, so_total desc)  
) WITH (MEMORY_OPTIMIZED=ON)  
GO  
  
-- cold portion of the SalesOrders - partitioned disk-based table  
CREATE PARTITION FUNCTION [ByDatePF](datetime2) AS RANGE RIGHT   
   FOR VALUES();  
GO  
  
CREATE PARTITION SCHEME [ByDateRange]   
   AS PARTITION [ByDatePF]   
   ALL TO ([PRIMARY]);  
GO  
  
CREATE TABLE dbo.SalesOrders_cold (  
   so_id INT NOT NULL,  
   cust_id INT NOT NULL,  
   so_date DATETIME2 NOT NULL,  
   so_total MONEY NOT NULL,  
   CONSTRAINT PK_SalesOrders_cold PRIMARY KEY (so_id, so_date),  
   INDEX ix_date_total NONCLUSTERED (so_date desc, so_total desc)  
) ON [ByDateRange](so_date)  
GO  
  
-- table for temporary partitions  
CREATE TABLE dbo.SalesOrders_cold_staging (  
   so_id INT NOT NULL,  
   cust_id INT NOT NULL,  
   so_date datetime2 NOT NULL,  
   so_total MONEY NOT NULL,  
   CONSTRAINT PK_SalesOrders_cold_staging PRIMARY KEY (so_id, so_date),  
   INDEX ix_date_total NONCLUSTERED (so_date desc, so_total desc),  
   CONSTRAINT CHK_SalesOrders_cold_staging CHECK (so_date >= '1900-01-01')  
)  
GO  
  
-- aggregate view of the hot and cold data  
CREATE VIEW dbo.SalesOrders  
AS SELECT so_id,  
   cust_id,  
   so_date,  
   so_total,  
   1 AS 'is_hot'  
   FROM dbo.SalesOrders_hot  
   UNION ALL  
   SELECT so_id,  
          cust_id,  
          so_date,  
          so_total,  
          0 AS 'is_hot'  
          FROM dbo.SalesOrders_cold;  
GO  
  
-- move all sales orders up to the split date to cold storage  
CREATE PROCEDURE dbo.usp_SalesOrdersOffloadToCold @splitdate datetime2  
   AS  
   BEGIN  
      BEGIN TRANSACTION;  
      -- create new heap based on the hot data to be moved to cold storage  
      INSERT INTO dbo.SalesOrders_cold_staging WITH( TABLOCKX)  
      SELECT so_id , cust_id , so_date , so_total  
         FROM dbo.SalesOrders_hot WITH ( serializable)  
         WHERE so_date <= @splitdate;  
  
      -- remove moved data  
      DELETE FROM dbo.SalesOrders_hot WITH( SERIALIZABLE)  
         WHERE so_date <= @splitdate;  
  
      -- update partition function, and switch in new partition  
      ALTER PARTITION SCHEME [ByDateRange] NEXT USED [PRIMARY];  
  
      DECLARE @p INT = ( SELECT MAX( partition_number) FROM sys.partitions WHERE object_id = OBJECT_ID( 'dbo.SalesOrders_cold'));  
      EXEC sp_executesql N'alter table dbo.SalesOrders_cold_staging  
         SWITCH TO dbo.SalesOrders_cold partition @i' , N'@i int' , @i = @p;  
  
      ALTER PARTITION FUNCTION [ByDatePF]()  
      SPLIT RANGE( @splitdate);  
  
      -- modify constraint on staging table to align with new partition  
      ALTER TABLE dbo.SalesOrders_cold_staging DROP CONSTRAINT CHK_SalesOrders_cold_staging;  
  
      DECLARE @s nvarchar( 100) = CONVERT( nvarchar( 100) , @splitdate , 121);  
      DECLARE @sql nvarchar( 1000) = N'alter table dbo.SalesOrders_cold_staging   
         add constraint CHK_SalesOrders_cold_staging check (so_date > ''' + @s + ''')';  
      PRINT @sql;  
      EXEC sp_executesql @sql;  
  
      COMMIT;  
END;  
GO  
  
-- insert sample values in the hot table  
INSERT INTO dbo.SalesOrders_hot VALUES(1,SYSDATETIME(), 1);   
GO  
  
INSERT INTO dbo.SalesOrders_hot VALUES(1, SYSDATETIME(), 1);  
GO  
  
INSERT INTO dbo.SalesOrders_hot VALUES(1, SYSDATETIME(), 1);  
GO  
  
-- verify contents of the table  
SELECT *  FROM dbo.SalesOrders;  
GO  
  
-- offload all sales orders to date to cold storage  
DECLARE  @t datetime2 = SYSDATETIME();  
EXEC dbo.usp_SalesOrdersOffloadToCold @t;  
  
-- verify contents of the tables  
SELECT * FROM dbo.SalesOrders;  
GO  
  
-- verify partitions  
SELECT OBJECT_NAME( object_id) , * FROM sys.dm_db_partition_stats ps  
   WHERE object_id = OBJECT_ID( 'dbo.SalesOrders_cold');  
  
-- insert more rows in the hot table  
INSERT INTO dbo.SalesOrders_hot VALUES(2, SYSDATETIME(), 1);  
GO  
  
INSERT INTO dbo.SalesOrders_hot VALUES(2, SYSDATETIME(), 1);  
GO  
  
INSERT INTO dbo.SalesOrders_hot VALUES(2, SYSDATETIME(), 1);  
GO  
  
-- verify contents of the tables  
SELECT * FROM dbo.SalesOrders;  
GO  
  
-- offload all sales orders to date to cold storage  
DECLARE @t datetime2 = SYSDATETIME();  
EXEC dbo.usp_SalesOrdersOffloadToCold @t;  
  
-- verify contents of the tables  
SELECT * FROM dbo.SalesOrders;  
GO  
  
-- verify partitions  
SELECT OBJECT_NAME( object_id) , partition_number , row_count  FROM sys.dm_db_partition_stats ps  
  WHERE object_id = OBJECT_ID( 'dbo.SalesOrders_cold') AND index_id = 1;

另请参阅

Memory-Optimized 表

通过

用于分区 Memory-Optimized 表的应用程序模式

代码示例

另请参阅

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