1. Big Data Working with Terabytes in SQL Server
Andrew Novick

2. Agenda What’s Big? Concerns Architecture Solutions
ETL/Load Performance
Query Performance
Backup/Restore Performance
Architecture
Solutions 2

3. Introduction Andrew Novick – Novick Software, Inc.
Business Application Consulting
SQL Server
.Net
Books:
Transact-SQL UDFs
SQL 2000 XML Distilled

4. SQL Pass 2008
November – Seattle

5. What’s big?

7. What’s Big? 100’s of gigabytes and up to 10’s of terabytes
100,000,000 rows an up to 100’s of Billions of rows

8. Big Scenarios Data Warehouse
Very Large OLTP databases (usually with reporting functions)

9. Big Hardware Multi-core 8-64 RAM 16 GB to 256 GB
SAN’s or direct attach RAID
64 Bit SQL Server

10. Concerns

11. What me worry?

12. Concerns Load Speed (ETL) Query Speed Data Management Backup / Restore
DBCC CHECKDB, remove Fragmentation 12

13. What do we have to work with?
Architecture
What do we have to work with?

14. SQL Server Storage Architecture
Table1
Table2
FileGroupA
FileGroupB
FileA1
FileB1
FileB2
Logical Disk System – Windows Drives
Drive C:
Drive D:
Drive E:
Physical IO - subsystem
Disk

15. Solutions

16. Solution to what? Load Speed (ETL) Query Speed Data Management
Backup / Restore
DBCC CHECKDB, remove Fragmentation 16

17. Solutions Use Multiple FileGroups/Files
Spread Data to maximize resource use
Sliding Window if there is a time dimension
Partitioned Tables and/or Views
ETL – Insert into empty unindexed tables
Use READ_ONLY FileGroups to minimize maintenance needs.

18. I/O Performance Little has changed in 50 years
Watch out for bottlenecks in the I/O Path
Memory reduces the need for I/O
Disks can only do so many I/O operations per second
The more disk heads you have the higher the I/O throughput.

19. At 3 PM on the 1st of the month: Where do you want your data to be?19

20. Spread to as many disk resources as possible.20

21. Sliding Window Always There Data Temporal Data 2008-01 Temporal Data
Temporal
Data
Temporal
Data
Temporal
Data

22. Read_Only FileGroups Require only one Backup
ALTER DATABASE <database> MODIFY FILEGROUP <filegroup> SET READ_ONLY
Require only one Backup
Don’t require page or row locks
Don’t require maintenance
The ALTER requires exclusive access to the database before SQL 2008

23. Concern - Load Performance (ETL)
4 Hour maximum window for any load
Load into large indexed tables is unacceptably long.
Example: 2 million row insert into 400 million row table with 10 indexes took 12 hours. 23

24. Concern – Query Performance
Users have little patience
Data warehouse Queries
Frequent small to medium to support UI
Less frequent large queries on fact tables may access 10’s of GB

25. Fact Table Queries Concentrated time period
Most recent
Year ago
May go against full table to get year-against-year 25

26. Dimension Table Queries
Smaller than fact table queries
Sometimes involve millions of rows
Frequent – support the UI

27. Partitioning 27

28. Partitioned Views Available in SQL Server Standard
Created like any view
Check constraints tell SQL Server which data is in which table
CREATE VIEW Fact AS
SELECT * FROM Fact_
UNION ALL SELECT * FROM Fact_
ALTER TABLE Fact_ ADD CONSTRAINT CK_FACT_ _Date CHECK (FactDate >= ‘ ’ and FactDate < ‘ ’ 28

29. Partitioned View - 2 Looks to a query like any table or view
Can take advantage of parallel execution.
Limited to 256 tables
Can cross servers (Performance Warning)
SELECT FactDate, … FROM Fact WHERE CustID= AND FactDate = ‘ ’

30. Partitioned View SQL Server Storage View Fact Table1 Table2
FileGroupA
FileGroupB
FGF1
FGF1
FGF2
FGF2
FGF3
FGF3
FGF4
FGF4
FileA1
FileB1
FileB2 F1 F1 F2 F2 F3 F3 F4 F4
Logical Disk System – Windows Drives
Drive C:
Drive D:
Drive E:
Physical IO - subsystem
Disk

31. Partition Elimination
The query compiler can eliminate partitions from consideration in the plan
Partition elimination happens at query compile time.
Values matching the partitioning column must be constants to allow partition elimination.

32. Demo 1 – Partitioned Views

33. Partitioned Tables SQL Server Enterprise SQL Server 2005 and Above
Require a non-null partitioning column
Check constraints tell SQL Server what data is in each parturition
All tables are partitioned! 33

34. Partitioned Tables 2 Partition Function Partition Scheme
Defines how to split data
Partition Scheme
Defines where to store each range of data
CREATE Partitioned View Fact_PF(smalldatetime) RANGE RIGHT FOR VALUES (‘ ’, ‘ ’)
CREATE PARTITION SCHEME Fact_PF AS PARTITION Fact_pf TO (PRIMARY, FG_ , FG_ )

35. Partitioned Table SQL Server Storage Table Fact Table1 Table2
Fact.$Partition=1
Fact.$Partitoin=3
Fact.$Partition=4
Fact.$Partition=2
FileGroupA
FileGroupB
FGF1
FGF2
FGF3
FGF4
FileA1
FileB1
FileB2 F1 F2 F3 F4
Logical Disk System – Windows Drives
Drive C:
Drive D:
Drive E:
Physical IO - subsystem
Disk

36. Demo 2 – Partitioned Tables

37. Partitioning Goals Adequate Import Speed Maximize Query Performance
Make use of all available resources
Data Management
Migrate data to cheaper resources
Delete old data easily 37

38. Achieving Load Speed Insert into empty tables
Index and add foreign keys after the insert
Add the Slices to
Partitioned Views
Partitioned Tables 38

39. Achieving Query Speed
Eliminate access to partitions during query compile
All disk resources should be used
Parallel access
All available memory should be used
All available CPUs should be used
Parallel query 39

40. Solution Partition at a sufficiently high grain
Spread dimension data to all useable disks
Separate Data and Index FileGroups
Multiple files per FileGroup
Spread Fact data by partition key to all useable disks
Rotate file locations to maximize dispersion 40

41. Concern – Data Management (Backup)
Let’s say you have a 10 TB database.
Now back that up.

42. Backup Calculation 10 TB = 10000 GB Typical Backup speed
Low end 1 GB per minute
High end 10 GB per minute
At 10 GB/Minute
Who’s got minutes?

43. Achieving Backup Performance
Backup less!
Maintain data in a READ_ONLY state
Compress Backups

44. Partial Backup Partial Base Partial Differential
Backs up read_write filegroups
Partial Differential
Differential backup of read_write filegroups
BACKUP DATABASE <db name>
READ_WRITE_FILEGROUPS …..
BACKUP DATABASE <db name>
READ_WRITE_FILEGROUPS
WITH DIFFERENTIAL ….

45. Maintenance Operations
Maintain only READ_WRITE data
DBCC CHECKFILEGROUP
ALTER INDEX
REBUILD PARTITION =
REORGANIZE PARTITION =
Avoid SHRINK

46. SQL Server 2008 – What’s New Row, page, and backup compression
Filtered Indexes
Optimization for star joins
MERGE T-SQL DML
Resource Governor
Fewer operations require exclusive access to the database

47. New England Visual Basic Pro
Focused on VB.Net development
MS Waltham – MPR C
1st Thursday - 6:15 to 8:30 PM
Sept 4 – Jim O’Neil – ASP.Net Dynamic Data
Sept 25 – Chris Hammond – DotNetNuke
Oct 2 – Kathleen Dollard – XML Litterals in VB 9
Nov 6 – Joe Stagner – Stupid Hacker Tricks and How 2 Defend
Feb 5 ’09 – Joe Hill – Novell – Mono/VB/etc….

48. Thanks for Coming Andrew Novick anovick@NovickSoftware.com