Introducing Hekaton The next step in SQL Server OLTP performance Mladen Prajdić

About me

First, a little history  SQL Server 7.0  Sybase origins  Completely rewritten storage engine  New locking mechanism  Data page from 2k to 8k  Dynamic memory and file management

First, a little history  SQL Server 2000  First 64bit version  Multiple instances on single machine  Materialized views and computed columns  Proper clustering  UDFs  performance problems -> awesome for consultants  XML  Instead Of triggers -> updateable views

First, a little history  SQL Server 2005  5 years  DMV’s and DMF’s  New snapshot transaction isolation levels  Service Broker  The basis for DB mirroring and Always ON  DDL triggers  CLR and XML integration  T-SQL improvements

First, a little history  SQL Server 2008 & 2008R2  New data types  Spatial, Hierarchy, Date, Time, DateTime2, …  Table Valued Parameters  Filestream  Resource governor  CDC & CT  Merge statement  Compression

First, a little history  SQL Server 2012  Always ON  Contained Databases  T-SQL enhancements  Full Text Semantic Search  Changed licensing   In memory technologies (xVelocity)  ColumnStore, Vertipaq, StreamInsight

SQL Server vNext HEKATON

HEKATON  Hekaton = Greek for 100x  In-Memory OLTP  Built directly into DB engine  High performance  Fully ACID  RDBMS are optimized for disk IO, SSDs help  CPU clock frequency flattened -> multicore  But… Memory started becoming cheap

HEKATON Computing power holds Moore Law due to parallelism CPU clock frequency stalled Memory has gotten a LOT cheaper

HEKATON - IO  No locks, latches, spinlocks or lock manager  No data pages or B-trees, row based  Stream based, no random IO  WAL guarantees ACID  T-Log records are much, much smaller

HEKATON - CPU & Memory  Separate from the SQL Server buffer pool  User settable, part of MAX server memory  No more memory it fails the operation  Scales linearly with the number of CPUs  Everything is done to minimize CPU cycles

HEKATON – T-SQL  Stored procedures compile to C, then to machine code  Bypasses the whole execution part in the engine  Not everything is supported  Calling a stored procedure is just a DLL entry point  Nothing radically new to learn

HEKATON – Data Structures  Lock free algorithms  Type of MVCC  Not in tempdb  Fully supported for HA, Backups, Log Shipping, etc  Durable and non durable tables  Data lost on restarts, schema fixed  Special filegroup, it’s filestream based  Tables must be migrated to the Hekaton filegroup

HEKATON – Data Structures  Bw-Tree index  Lock free b-tree index  Not a skip list  Demonstrated by MS research two years ago  Works on delta tables  For more details there’s a research paper on it

HEKATON – Coding scenarios: Transaction/Sec Normal stored procedure and table Normal stored procedure and Hekaton table Hekaton stored procedure and table

HEKATON – Coding scenarios: CPU Normal stored procedure and table Normal stored procedure and Hekaton table Hekaton stored procedure and table

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