1. Introduction to Partitioning in SQL Server
Remember Legos? It’s kind of like that...

2. A Little About Me
@SQLServerNerd
Event Chair
Forums Administrator

3. Have you ever wanted to…/secrets of heavy hitter servers
Truncate just part of a table
Migrate data from one table into another in milliseconds
Spread your table over different tiers of storage.
Perform maintenance on just part of a table
Access just part of a table/index for less IO
Have locks escalate to just a segment of a table instead of a table lock

4. What is partitioning?
A way to break tables down into smaller chunks for manageability and performance

5. You mean it will help me to…
Reduce IO impact via partition elimination
Improve join operations for equi-joins when both tables are partitioned on the same column and joined on the partitioned column
Move data in and out of tables really fast

6. Horizontal partitioning VS vertical partitioning
Vertical partitioning is splitting out extra columns into their own table(s)
Horizontal partitioning is when we break up our table based on rows
This is what we traditionally mean when using the word partition
This is what we will talk about today

7. What techniques will we cover.
We’ll start with the much simpler partitioned view
We’ll spend a lot more time on table partitioning.

8. An Oldie but a goodie: The partitioned view
Separate tables with a view that brings them together
Check constraints on the underlying tables allow the optimizer to perform “partition elimination”

9. Demo: Partitioned views

10. Table Partitioning Overview
Introduced in SQL Server 2005
Its and enterprise only feature
Invisible to queries
More complex than partitioned views

11. How is it implemented in SQL Server
Every table has at least one partition
These partitions exist in files
The files are part of a filegroup
Each partition is like a mini table, with its own IAM chain. In other words it’s a separate “object” in the database
It’s the combination of all partitions that form the actual table

12. How is it implemented in SQL Server
Partitions also allow another level of locking called a partition lock. This can be amazingly beneficial

13. Data Files
These are the actual files on disk with an mdf or ndf extension
All objects in a database are stored in one or more files
If multiple files exist within a file group then data is spread across them with a round robin algorithm, with preference given to the smallest file

14. Filegroups Provide a “Container” to group data files into
Objects in the database are created against a filegroup

15. Partition Functions Are used to assign rows to partitions
Can only work on one column known as the partition key
Range left and Range right determine where the boundry value falls

16. Partition Schemes
Are used to place partitions into one or more filegroups
They specify the destination of the data
ALL TO allows you to have all partitions exist in one filegroup
Partitioned tables are built not on a single filegroup but on a partition scheme

17. Aligned Indexes Indexes can be partitioned as well
If an index is created on the same partition scheme as its parent table, it is said to be aligned.
This allows for maintenance on just one part of the index

18. Demo: Example partitioned table/files/filegroups
Creating a partitioned table
Verifying our partitions: sys.dm_db_partition_stats/sys.partitions

19. Partition management Overview
We can move chunks of data in and out of tables really fast using partitions as long as the data is all in the same filegroup
We can switch data in, or out, from another table in milliseconds regardless of size. This is possible because the switch is really only a metadata one.
The tables must have the same design however
We can merge partitions together, or split them apart, during our loads. Again this is a metadata operation

20. Splitting partitions up
We can split partitions up using the split command
The split command is part of the alter partition function statement
We split by defining a new range

21. Merging partitions together.
The merge command allows you to combine partitions into one partition
This is done by merging our ranges
It is part of the alter partition function statement

22. Moving partitions between tables
We can use the switch command to move partitions between tables
Indexes must be identical on both tables
The tables must also share the same constraints
The tables must be part of the same filegroup
Both tables must exist already
Transfer into a partitioned table, requires that the destination partition exist and be empty
Non partitioned tables must be empty

23. DEMO: Switch