SQL Server 2014 In-Memory OLTP (Hekaton) Detaylı Bilgi İçin : http://www.btakademi.com/

1. İsmail Adar

2. About.Me()
• Veritabanı Yöneticisi / Doğan Online
• Eğitimen/Danışman / Btakademi
• Kitap Yazarı
• Microsoft Certified Trainer
ismailadar@hotmail.com
http://www.ismailadar.com
İsmail
Adar
@ismailadars

3. Content.GetAgenda()
• SQL Server 2014 In-Memory OLTP Basics
• Create Database For In-Memory OLTP
• Creating Memory Optimized Tables and Indexes
• Accessing Memory Optimized Tables
• Memory Optimized Tables Limitations
• Memory management on memory-optimized tables
• Tools for analysis and migration

4. SQL Server 2014 In-Memory OLTP Basics

6. Create Database For In-Memory OLTP
code page 1252
associated collation
CREATE DATABASE [InMemoryDemo] COLLATE Latin1_General_CI_AI
GO
ALTER DATABASE [InMemoryDemo]
ADD FILEGROUP [InMemory_FStream_FGroup]
CONTAINS MEMORY_OPTIMIZED_DATA
Filegroup for memory optimized
table storage
GO
ALTER DATABASE [InMemoryDemo] ADD FILE ( NAME = N'InMemoryDemo_FS',
FILENAME = N'C:Program FilesMicrosoft SQL
ServerMSSQL12.MSSQLSERVERMSSQLDATAInMemoryDemo_FS' )
TO FILEGROUP [InMemory_FStream_FGroup]
GO
Add file to FS filegroup

7. DEMO
Creating Database For In Memory OLTP

9. Create Table DDL
Hash Index
CREATE TABLE [Customer](
BUCKET_COUNT 1-2X nr of
unique index key values
[CustomerID] INT NOT NULL
PRIMARY KEY NONCLUSTERED HASH WITH (BUCKET_COUNT = 1000000),
[Name] NVARCHAR(250) NOT NULL,
[CreatedDate] DATETIME NULL
INDEX [IX_CreatedDate] NONCLUSTERED
)
Indexes are specified inline
NONCLUSTERED indexes are
supported
WITH (MEMORY_OPTIMIZED = ON, DURABILITY = SCHEMA_AND_DATA);
This table is memory
optimized
This table is durable

10. Memory Optimized Table Creation
CREATE TABLE DDL
Code generation and compilation
Table DLL produced
Table DLL loaded

11. DEMO
Creating Memory Optimized Tables

12. Memory-Optimized Indexes
•
Exist only in memory
– Rebuilt on database startup
•
Do not contain data rows
– Indexes contain memory pointers to the data rows
– No duplication of data
– All indexes are covering

13. Memory-optimized Table: Row
Format
Row header
Payload (table columns)
8 bytes * (IdxLinkCount)
Begin Ts
End Ts
StmtId
IdxLinkCount
8 bytes
8 bytes
4 bytes
2 bytes

14. Memory Optimized Tables and Hash Indexes
Timestamps
Hash index on
Name
50, ∞
Chain ptrs
Name
City
Hash index on
City
Jane
Prague
100, ∞
John
Prague
90, ∞
90, 150
Susan
Bogota

15. Nonclustered (range) index
•
No latch for page updates
•
No in-place updates on index pages

•
1
PAGE
Physical
Page size- up to 8K. Sized to the row
•
Page Mapping Table
0
Handled thru delta pages or building new pages
Sibling pages linked one direction

Root
PAGE
2
1
0
3
2
0
•
2
8
Require two indexes for ASC/DSC
No covering columns (only the key is stored)
Page-pid-0
PageID-3
4
8
1
0
1
1
1
5
1
8
2
1
2
4
2
7
Non-leaf pages
Logical
1
14
15
2
200,
4
∞
5
1
Key
6
2
5
7
50, 300
2
Key
2
6
2
7
Data rows
leaf pages

16. DEMO
Creating Indexes On Memory Optimized Tables

18. Create Procedure DDL
CREATE PROCEDURE [dbo].[InsertOrder] @id INT, @date DATETIME
WITH
This proc is natively
compiled
NATIVE_COMPILATION,
SCHEMABINDING,
Native procs must be
schema-bound
EXECUTE AS OWNER
Execution context is
required
AS
BEGIN ATOMIC
WITH
Atomic blocks
• Create a transaction if
there is none
• Otherwise, create a
savepoint
(TRANSACTION
ISOLATION LEVEL = SNAPSHOT,
LANGUAGE = N'us_english')
-- insert T-SQL here
END
Session settings are fixed at
create time

19. Procedure Creation
CREATE PROC DDL
Query optimization
Code generation and compilation
Procedure DLL produced
Procedure DLL loaded

20. Accessing Memory Optimized Tables
Interpreted T-SQL Access
• Access both memory- and disk-based
tables
• Less performance
Natively Compiled Stored
Procs
• Access only memory optimized tables
• Maximum performance
• Limited T-SQL surface area
• Virtually full T-SQL surface
• When to use
– Ad hoc queries
– Reporting-style queries
– Speeding up app migration
• When to use
– OLTP-style operations
– Optimize performance critical business logic

21. Sample AdventureWorks conversion
ostress.exe -S. –E
-dAdventureWorks2012
-Q"EXEC Sales.usp_InsertOrders
@use_inmem = <0,1>,
@order_count=100000"
–n<varies>

22. DEMO
Accessing Memory Optimized Tables

24. Limitations on In-Memory OLTP in SQL 2014
• Tables
–
–
–
–
–
–
Triggers: no DDL/DML triggers
No Identity columns
Data types: no LOBs, no XML and no CLR data types
Constraints: no FOREIGN KEY and no CHECK constraints
No schema changes (ALTER TABLE) – need to drop/recreate table
No add/remove index – need to drop/recreate table
• Natively Compiled Stored Procedures
– No outer join, no OR, no subqueries, no CASE
– Limited built-in functions [core math, date/time, and string functions are
available]

26. Memory Management For In-Memory OLTP
Data resides in memory at all times
• Must configure SQL server with sufficient memory to store memoryoptimized tables
• Failure to allocate memory will fail transactional workload at run-time
• Integrated with SQL Server memory manager and reacts to memory
pressure for GC (Garbage Collection)

27. Memory Management For In-Memory
OLTP
Integrated with Resource Governor
• To ensure performance stability for disk-based table workloads
• “Bind” a database to a resource pool
• Mem-opt tables in a database cannot exceed the limit of the resource
pool
• Hard top limit (80% of phys. memory) to ensure system remains stable
under memory pressure

28. Memory Management For In-Memory OLTP
Memory optimized max
memory limit
CREATE RESOURCE POOL InMemResourcePool
WITH (MAX_MEMORY_PERCENT=40);
ALTER RESOURCE GOVERNOR RECONFIGURE;
GO
EXEC sp_xtp_bind_db_resource_pool 'InMemoryDemoDB','InMemResourcePool';
GO
ALTER DATABASE InMemoryDemoDB SET OFFLINE;
ALTER DATABASE InMemoryDemoDB SET ONLINE;
Filegroup for memory optimized
table storage

29. DEMO
Memory Management For In-Memory OLTP

31. DEMO
Analysis and Migration Tools

32. Resources
•
Overview of all In-Memory OLTP posts on the SQL Server blog
–
http://blogs.technet.com/b/dataplatforminsider/archive/2013/10/15/the-411-on-the-microsoft-sql-server-2014-in-memory-oltp-blog-series.aspx
•
SQL 2014 CTP2
–
http://technet.microsoft.com/en-US/evalcenter/dn205290?WT.mc_id=Blog_SQL_InMem_CTP2
•
Getting started with In-Memory OLTP
–
http://blogs.technet.com/b/dataplatforminsider/archive/2013/06/26/getting-started-with-sql-server-2014-in-memory-oltp.aspx
•
In-Memory OLTP Sample, based on AdventureWorks
–
https://msftdbprodsamples.codeplex.com/releases/view/114491?WT.mc_id=Blog_SQL_InMem_CTP2
•
Analysis and Migration tools
–
–
http://technet.microsoft.com/en-us/library/dn284308(v=sql.120).aspx
–
•
http://technet.microsoft.com/en-us/library/dn205133(v=sql.120).aspx
http://technet.microsoft.com/en-us/library/dn358355(v=sql.120).aspx
Transaction isolation with In-Memory OLTP
–
Choosing isolation level: http://msdn.microsoft.com/en-us/library/dn133187(v=sql.120).aspx
–
Implement retry logic: http://msdn.microsoft.com/en-us/library/dn169141(v=sql.120).aspx
•
Books Online documentation for In-Memory OLTP
–
http://technet.microsoft.com/en-us/library/dn133186(v=sql.120).aspx
•
Limitations and workarounds
–
http://msdn.microsoft.com/en-us/library/dn247639(v=sql.120).aspx

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