SQL Server 2014 In-Memory Technologies.

Transcription

1 SQL Server 2014 In-Memory Technologies

2 Agenda Columnstore technology Clustered columntore index Nonclusterd columnstore index Memory-optimized tables Summary

3 Columnstore technology Highlights Storage

4 Columnstore Index - Highlights Nonclustered index introduced in SQL Server 2012 Clustered index introduced in SQL Server 2012 Technology for storing, retrieving and managing data in-memory Data stored in column-based format instead of traditional row-based 10x query performance gains Data is compressed up to 7x over the uncompressed data size Use Case: Large data warehousing fact tables and dimensions.

5 Columnstore Index - Storage

6 Clustered columnstore index Highlights How to use it? Demo

7 Clustered columnstore index Highlights Only one index for the entire table Index is updateable - insert, update, and delete Table cannot not contain columns of certain data types (i.e. binary, varchar(max), xml) Table cannot be configured with any unique, primary key or foreign key constraints

8 Clustered columnstore index How to use it? CREATE CLUSTERED COLUMNSTORE INDEX index_name ON [database_name. [schema_name ]. schema_name. ] table_name [ WITH ( MAXDOP = max_degree_of_parallelism ) ] [ ON <on_option> ] [ ; ] WITH DROP_EXISTING = [OFF] ON specifies to drop the existing clustered columnstore index, and create a new columnstore index. MAXDOP = Use MAXDOP to limit the number of processors used in a parallel plan execution. The maximum is 64 processors. ON = Specify the filegroups or partition sheme on which the index will be created CREATE CLUSTERED COLUMNSTORE INDEX my_cci ON MyFactTable

9 Clustered columnstore index Demo Query table with traditional indexes Analyse the performance Create columnstore clustered index Query table Analyse performance difference

10 Nonclustered columnstore index Highlights How to use it? Demo

11 Nonclustered columnstore index Highlights Can index a subset of columns in a table. Index is read-only Can be combined with other indexes Is available in all editions of SQL Server 2014 Cannot be created on a view or indexed view. Cannot include a sparse column. Some data types are not supported (i.e. binary, varchar(max), xml)

12 Nonclustered columnstore index How to use it? CREATE NONCLUSTERED COLUMNSTORE INDEX index_name ON [database_name. [schema_name ]. schema_name. ] table_name( column [,...n ] ) [ WITH ( < with_option> [,...n ] ) ] [ ON <on_option> ] [ ; ] CREATE NONCLUSTERED COLUMNSTORE INDEX cidx_factsalesorder ON FactSalesOrder (CustomerKey, SalesPersonKey, SalesAmount, Quantity)

13 Nonclustered columnstore index Demo Create noclustered index Attempt to update the data Disable the index Update the data Rebuild the index

14 Memory-Optimized tables Highlights How to use it? Demo

15 Memory-Optimized tables - Highlights Memory-optimized tables reside in memory. A second copy of the table data is maintained on disk, but only for durability purposes. A database can contain in-memory as well as disk-based objects Rows in memory-optimized tables are versioned to allow concurrent reads and writes on the same row Option of Non-durable memory-optimized tables, but the data will not be recovered if there is a server crash or failover. Table Partitioning is supported. Limited amount of active data is kept inmemory, while older data is kept on disk With memory-optimized table variables there is no tempdb utilization.

16 Memory-Optimized tables How to use it? CREATE TYPE [dbo].[usersession] AS TABLE( [SessionId] [int] NOT NULL, [UserId] [int] NOT NULL, [ShoppingCartId] [int] NOT NULL, [CreatedDate] [DateTime] NOT NULL, INDEX [IX_SessionID] HASH ([SaleID]) WITH ( BUCKET_COUNT = 8)*, INDEX [IX_UserID] NONCLUSTERED ) WITH ( MEMORY_OPTIMIZED = ON ) * bucket count should be between 1 and 2 times the number of distinct values in the index key

17 Memory-Optimized tables Demo? Create memory-optimized table Insert data Select data