Introduction to the Federations horizontal scale-out feature of Windows Azure SQL Database.

1. SQL Database Federations
Scaling out relational data in Windows Azure
NEIL MACKENZIE

2. Who Am I?
 Neil Mackenzie
 Azure Architect @ Satory Global
 Windows Azure MVP
 Blog: http://convective.wordpress.com/
 Twitter: @mknz
 Book:
Microsoft Windows Azure Development Cookbook

3. Content
 Windows Azure Platform
 Motivation for SQL Database Federations
 Overview of SQL Database Federations
 Transact-SQL Statements
 DMVs
 Fan-out queries

4. Windows Azure
 Cloud Services:
 Platform-as-a-Service
 Web roles, worker roles
 Infrastructure-as-a-Service
 Virtual Machines, SQL Server 2012
 Connectivity
 Endpoints, Virtual Network, Service Bus
 Storage
 Windows Azure Storage Service
 Windows Azure SQL Database

5. SQL Database
 Database-as-a-Service
 Multi-tenanted
 Priced in GB/month
 Database
 One primary and two secondary databases
 Quorum commit
 Maximum size: 150GB
 Programmability
 TDS protocol
 SQL Server authentication
 Change connection string and go

6. Scalability
 Scale up
 Use more powerful hardware
 Price/performance problem
 Fails at internet scale
 Scale out
 Use commodity hardware
 Cost-effective way to increase performance
 Resilient towards failure

7. Scale-Out Data
 Use multiple databases (shards)
 Sharding provides:
 Larger data sizes
 Higher performance
 Issues:
 Data distribution
 Connection routing

8. SQL Database Federations
 Sharding-as-a-Service
 Federated database comprises:
 Root database
 Federation member databases (shards)
 Federation specified by:
 Federation name
 Distribution key
 Routing
 Connection pooling

9. Federation Members
 Federation member
 Federated data distributed by distribution key range
 Error to insert or update distribution key outside range
 Member databases can have:
 different sizes
 different schemas
 Distribution key in:
 Clustered index
 Each unique index

10. Table Types
 Federated tables
 In federation members
CREATE TABLE ( … )
FEDERATED ON (CustomerId = custId)
 Reference tables
 In federation members
CREATE TABLE ( … )
 Common tables
 In root database

11. Federation Operations
 Transact SQL support for federations:
 CREATE FEDERATION
 USE FEDERATION
 ALTER FEDERATION
 DROP FEDERATION

12. CREATE FEDERATION
 CREATE FEDERATION federation_name
(distribution_name <data_type> RANGE)
 Data types:
 INT
 BIGINT
 UNIQUEIDENTIFIER
 VARBINARY(n) - n<=900
 Root database can support several federations
 e.g. – customer federation, product federation

13. USE FEDERATION
 USE FEDERATION ROOT WITH RESET
 Routes connection to root database
 USE FEDERATION federation_name
(distribution_name = value)
WITH RESET, FILTERING={ON|OFF}
 Routes connection to appropriate federation member
 FILTERING= OFF allows connection to be used for any data in the
federation member
 FILTERING=ON restricts connection to a specified distribution
key

14. ALTER FEDERATION: SPLIT
Range: 100 400 500
ALTER FEDERATION CustomerFederation
SPLIT AT (CustomerId = 200)
Range: 100 200 400 500

15. ALTER FEDERATION: DROP
100 200 400 500
ALTER FEDERATION CustomerFederation
DROP AT (LOW CustomerId = 200)
100 200 400 500
ALTER FEDERATION CustomerFederation
DROP AT (HIGH CustomerId = 200)
100 200 400 500

16. Dynamic Management Views
 Definition
 e.g. sys.federation_member_distributions
 History
 e.g. sys.federation_member_distribution_history
 Operations
 e.g. sys.dm_federation_operations
 Operation errors
 e.g. sys.dm_federation_operation_errors

17. sys.federation_member_distributions
 Columns
 federation_id int
 member_id int (database id)
 Distribution_name sysname
 Range_low sqlvariant
 Range_high sqlvariant
 Range:
 includes Range_low
 excludes Range_high

18. Security Principal
 Root database
 CREATE USER user_name FROM LOGIN login_name
 Federation member
 CREATE USER user_name
 Security is otherwise like SQL Database

19. Fan-Out Queries
 Loop over:
 sys.federation_member_distributions.Range_low
 Perform queries in parallel
 Two-step process
 Member query
 Summary query (if necessary)

20. Summary
 SQL Database Federations
 Sharding-as-a-Service
 Elastic scalability for SQL Database databases
 Management support
 Developer support

21. More Information
 MSDN Wiki
http://bit.ly/A7sUdo
 Cihan Biyikoglu blog:
http://blogs.msdn.com/b/cbiyikoglu/
 Post based on this presentation:
http://bit.ly/wqD4Xo