Introduction to Columnstore Indexes

Jason
Strate
e: jstrate@pragmaticworks.com
e: jasonstrate@gmail.com
b: www.jasonstrate.com
t: StrateSQL
Resources jasonstrate.com/go/indexing
Introduction
MAKING BUSINESS INTELLIGENT
www.pragmaticworks.com

• Industry leaders in Microsoft BI and SQL Server
Platform
• SQL Server Professionals - PASS Board of Directors,
Speakers, Authors and MVP’s
• National Sales Team Divided by Microsoft
Territories
• National System Integrator (NSI)
• Gold Certified in Business Intelligence and Data
Platform
• Platform Modernization/Safe Passage
• Premier Partner for PDW SI Partner Program
MS PDW Partner of Year FY13
Frontline Partnership Partner of the Year for Big Data
Executive sponsor - Andy Mouacdie, WW sales director
PDW
• Over 7,200 customers worldwide
• Over 186,000 people in PW database for demand
generation
About Pragmatic Works

Everyone wants
fast queries

Sometimes Normal
Doesn’t Make Sense

To get things
back to normal

Agenda
Introduction Columnstore Basics
SQL Server
Columnstore
Non-Clustered
Columnstore
Clustered
Columnstore
Summary

Session Goals
• Identify differences between rowstore and
columnstore indexes
• Describe implementation of columnstore index
in SQL Server
• Define pros and cons with columnstore indexes
• Demonstrate use of columnstore indexes

Index Problems
• Indexes traditionally are row-based
– All columns for row stored together
• Any column read brings over all columns
– Impacts IO, CPU, and memory
– Typically 15% of DW columns in queries
• Databases growing 10x every 5 years
• Tuning for over indexing, under indexing, and
bookmark lookups

Columnstore Basics
• Change data storage from row to column
based
– Rowstores
– Columnstores
• Data grouped by columns
– One column per grouping (segment)
– Data access at columns level
– Only return columns required for query

Say
What?!

Traditional Index

Columnstore Index

Why Columnstore?
• Improved query performance
– Column centric reads
– Heavy data compression
– Processing by batch versus row
• Improved resource utilization
– Smaller index space
– Less memory required

SQL Server Columnstore
• Introduced to improve data warehouse
performance
• Available since SQL Server 2012
• SQL Server 2012
– Non-clustered columnstore
• SQL Server 2014
– Clustered columnstore

Columnstore Attributes
• Introduced in SQL Server 2012
• Supports batch mode processing
• SQL Server 2012
– Non-clustered columnstore
– No key columns
– Support partitioning
– Read only index
• SQL Server 2014
– Clustered columnstore
– Columnstore archive format
– Readwrite when clustered

Batch-mode Processing
1 record versus 415 records

Columnstore Restrictions
• Cannot be a unique index.
• Cannot be created on a view or
indexed view.
• Cannot include a sparse
column.
• Cannot act as a primary key or
a foreign key.
• Cannot be created with
the INCLUDE keyword
• Cannot include
the ASC or DESC keywords for
sorting the index
• No seek operations
• Cannot contain a column with a
FILESTREAM attribute
• Limited data types
– Except varchar(max),
nvarchar(max), binary,
varbinary, ntext, text, image,
uniqueidentifier, rowversion,
timestamp, sqlvariant, xml, CLR
types
• Feature restrictions
– Replication
– Change tracking
– Change data capture
– Filestream

Non-Clustered Columnstore
• Available in:
– SQL Server 2012
– SQL Server 2012 Parallel Data Warehouse
– SQL Server 2014
• One non-clustered columnstore per table
– Support tables heap or clustered index
• Add in all columns from table
– No key columns
• Best support star-join style queries
• Avoid OUTER JOIN and NOT IN
– Prevent batch processing

Updating Non-Clustered Columnstore
• Drop the columnstore
• Perform DML
• Recreate columnstore
Drop and
Rebuild
• Create new partition with modified data
• Create columnstore
• Switch in partition
Partition
Switch
• Apply changes to separate table
• UNION ALL columnstore or change table
• Manage DML through trigger
Partitioned
View

NON-CLUSTERED COLUMNSTORE
Demo

Clustered Columnstore
• Available in:
– SQL Server 2012 Parallel Data Warehouse
– SQL Server 2014
• One clustered columnstore per table
– Is primary storage for data
– Reduces space requirements
• Can leverage columnstore archive format
• Same design patterns as non-clustered
• Preferred over non-clustered columnstore

CLUSTERED COLUMNSTORE
Demo

Summary
• Columnstore indexes change data can be
accessed
• Provides increased data compression
• Retrieves only the columns that are needed
• Primary benefit in data warehouses
– Slowly or unchanging data

More Information
Expert Performance Indexing
For SQL Server 2012
Jason Strate
Ted Krueger
Overview
Statistics
Maintenance
Tools
Analysis
http://amzn.com/1430237414

Services
Speed development through training, and
rapid development services from
Pragmatic Works.
Products
BI products to covert to a Microsoft BI
platform and simplify development on
the platform.
Foundation
Helping those who do not have the
means to get into information technology
achieve their dreams.
For more information…
Name: Jason Strate
Email: jstrate@pragmaticworks.com
Blog: www.jasonstrate.com
Resource: jasonstrate.com/go/indexing
Need Help? jasonstrate.com/go/vmdba

Introduction to Columnstore Indexes

More Related Content

What's hot

Similar to Introduction to Columnstore Indexes

More from Jason Strate

Recently uploaded

Introduction to Columnstore Indexes