by Niko Neugebauer

• PASS Evangelist
• SQL Server MVP
• SQLPort ( http://www.sqlport.com
) founder & leader
• BITuga ( http://www.bituga.pt
) co-founder
• 15+ years in IT

HEK-A-TON, HEK-A-TON, HEK-A-TON

• ἑκατόν – means 100 in Greek
• Targeted to improve OLTP performance, 100 Times

• Imagine that you have a number of CPU steps to perform a typical OLTP action
• Optimize it 100 times by removing obstacles like latches and parallelize it
• Yes, you will need start from the bottom and from the very beginning?

• Look at the CPU speed increase
• Look at the Memory Prices
• You can’t buy a SQL Server Enterprise License for a price of a TB
• Think, think, think 

Hekaton

Sybase SQL Server 1.0
• 1980 (1989)
• Hardware Expensive
• CPU Bound
• Pages 8K
SQL Server 11.0
• 2012
• Hardware Cheap
• IO & Memory Bound
• Pages 8K

• In-Memory Database
• Multi-Core Awareness and Optimizations
• xVelocity compression algorithm (hint: ColumnStore)
• No Pages (no more splits, allocations, etc)
• No Locks, No Latches + different Concurrency Control
• StreamInsight (no more 8K’s)
• Hash Index (no more b-trees)
• Existing T-SQL can be reused

• Highly scalable concurrency control mechanism
• Lock-free data structures

• ACID compliant
• Optimized for extreme Transaction Processing scenarios like
• Financial Services
• Online Gambling
• There are customers who are using it NOW

Hekaton

• Snapshot_Isolation ONLY
• No support for LOB data types
• No Triggers
• AlwaysOn Support

• Durable Tables
• Non-Durable Tables
• TempDB is used inside of the Hekaton, in-memory
• Shares memory with Buffer Pool, but has its own space

• Different space allocation for memory buffer
• The very same transaction log, but with fewer writes
• Different filegroups
• Different treatment for Indexes
• A lot of new, different stuff 

It actually looks like a …

• Create table dbo.Hekaton(
• Id int primary key hash with (bucketcount = 65535),
• Nome varchar(50)
) WITH (MEMORY_OPTIMIZED = ON, DURABILITY
= SCHEMA_AND_DATA );
GO

Stored Procs:
• Uses C as internal intermediate presentation, and then compiles into native code
• Atomic blocks
• Can’t reference non-hekaton tables

• Create procedure dbo.HekatonNow
• WITH NATIVE_COMPILATION
BEGIN
END
GO select name from dbo.Hekaton;

• Uses StreamInsight
• No actual updates, but deletes & inserts

• Migration from the normal DB tables to Hekaton
• Stored Procedures Migration to Hekaton

Next major version of SQL Server

• Isn’t it too fast ?
• – No, there is no such concept as too fast. (as long as it does not create other problems)