This document discusses different types of database partitioning including horizontal, vertical, and file group partitioning. It provides examples and definitions of each type. Key benefits highlighted include improved performance through better query plans, reduced backup sizes, and ability to do partial database restores for high availability. The document also discusses considerations for determining good candidates for partitioning and demonstrates partitioning techniques.

1. Partitioning Design
For Performance and Maintainability
Martin Cairns
http://sqlbyparts.com
http://twitter.com/MartinCairnsSQL

2. Who am I?

3. Partitioning Defined
Partitioning (noun)
1. the action or state of dividing or being
divided into parts
2. a structure dividing a space into two parts
Source: http://oxforddictionaries.com/definition/english/partition

4. Types of Partitioning
• Horizontal
• Partition Table by Rows
• Vertical
• Partition Table by Columns
• File Group
• Partition Tables by File Group

5. Horizontal Partitioning
 Divides the rows into small sets by
boundaries
Year PK Order ID Product ID Qty Cost Line XML
2010 1 1 1 5 1.5 <Line…
2010 2 1 1 7 2 <Line…
2011 1000000 20000 345 1000 5 <Line…
2011 1000001 20000 347 3000 12 <Line…
2012 2000000 40000 705 8000 3 <Line…
2012 2000001 40001 706 3000 7 <Line…

6. Vertical Partitioning
 Divides columns from one table into multiple
tables
Year PK Order ID … Year PK Line XML
2010 1 1 … 2010 1 <Line…
2010 2 1 … 2010 2 <Line…
2011 1000000 345 … 2011 1000000 <Line…
2011 1000001 347 … 2011 1000001 <Line…
2012 2000000 705 … 2012 2000000 <Line…
2012 2000001 706 … 2012 2000001 <Line…

7. File Group Partitioning
 File group partitioning is separating the storage of tables
and indexes onto separate database files
 During a Primary File Group restore the whole database
will be offline
 Separate the system & user tables to allow the quickest
restore time
 Since the partitioned database is made up of smaller
parts it is easier to manage the storage location of the
files

8. Using Table Partitioning
 Supports Horizontal Partitioning
 Partition Function defines boundaries based
on a single column
 Partition Scheme defines the File Group
 Inserts automatically supported
 All partitions share the same definition as the
table (indexes, columns, fill factor etc)

9. Table Level Limitations
 Only ~200 steps for each statistics across the
whole table
 Online Index rebuilds are for the whole table
not individual partitions
 Fill Factor
 Lock settings (Row, Page, Escalation, etc)
 Indexes are defined for the whole table rather
than partitions

10. Using View Partitioning
 View Partitioning allows you to overcome
Table Level Constraints
 Check Constraints used to define partitions
 Combine all tables with a UNION ALL View
 Can be used together with Table Partitioning
 Trigger required to allow INSERT with Identity
column
 Allows more complex partitioning schemes

11. Candidates for Partitioning
 Large vs. Small Tables
 Replicated vs. Non-Replicated Tables
 Normal vs. BLOB columns
 Write Heavy Current data vs. Heavily
Read Historic data
 Read Write vs. Read Only Tables

12. Partial Database Availability
 Also referred to as Piecemeal Restore
 Full Recovery Model is Required
 Individual File & File Groups Restore
 Only the Primary File Group is required to
restore a database
 Allows restoring a subset of a correctly
partitioned database for quicker recovery
from a disaster

13. Tipping Point Why is it Table Scanning
 As the number of rows in a table increase the
depth of the B+Tree increases
 The number of Page Reads for a lookup is
equal to the depth of the B+Tree
 The Tipping Point is the point where a Full
Table Scan requires less Page Reads than
the lookups

14. What Does Partition Give Us
 Choices
 Using different Tiers of Storage
 Allows quicker recovery strategies
 Allows partial restores of the database
 Performance
 Allows reduction of overhead of backups
 Allows better query plans due to more
accurate statistics on large tables

15. Demos
 Moving Tables to File Groups
 Partial Restore + Using Partial Restore to
Initialise Replication
 Moving Partition Between Tables For Current
vs. Historic
 Show how View Partitioning can present a
single view of all tables & still support
partition elimination