The document discusses Azure throttling, explaining its definitions and implications for SQL databases in a multi-tenant environment, including soft and hard throttling mechanisms. It outlines resource governance factors such as limits on worker threads, sessions, and database size, along with various error codes related to throttling. Additionally, it suggests solutions for managing throttling issues, such as using retry policies with Entity Framework and considering premium database offerings.

1. Windows Azure Throttling

2. Windows Azure Throttling
TalentSoft
Julien PLEE
Responsable R&D
TalentSoft
jplee@talentsoft.com, @julplee

3. AZURE THROTTLING
What is throttling?
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4. Windows Azure Sql Database Case
• Multi-Tenant
• Resource Management
– Resource Governance
– Resource Limits
– Engine Throttling
• Affects multiples services
• Sql Database Network
Topology
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5. Windows Azure Sql Database
Une seule base
de données
logique
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Plusieurs réplicas
physiques
Primaire
unique
Plusieurs cibles
secondaires
Réplica 3 Réplica 2 Réplica 1

6. Soft Throttling
• Throttles the activities of a
subset of Sql Databases that
consume most resources
Hard Throttling
• Final Stage.
• No more connections are
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allowed until resources are
freed up
Engine Throttling
40501: The service is currently busy. Retry the request after 10 seconds.
Incident ID: <ID>. Code: <code>.

7. Resource Governance
• Worker Threads and Sessions limits
• Depends on Web/Business/Premium mode
• Error code differs from Engine Throttling
(10928)
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8. Resource Limits
• Database Size
• Transaction Duration
• Transaction Lock Count
• tempdb
• Transaction Log Length
• Memory Usage
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9. AZURE THROTTLING
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10. AZURE THROTTLING
How to solve problems?
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11. Azure Throttling & Transient Fault Handling
Solutions
• Entity Framework 6
• Enterprise Library 5.0 Integration Pack for
Windows Azure
• More money: Sql Database Premium
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12. Sql Database Premium
Reservation
Size
CPU Cores
Worker
Threads
Active
Sessions
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Disk IO
(IOPS)
Memory
(GB)
P1 1 200 2000 150 8
P2 2 400 4000 300 16

13. AZURE THROTTLING
Manage throttling
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14. Hello Talent Case: TransactionInterceptor.cs
public void Intercept(IInvocation invocation)
{
...
if (Transaction.Current == null)
{
RetryPolicy policy = new RetryPolicy<SqlDatabaseTransientErrorDetectionStrategy>(...);
var transactionOptions = ...
policy.ExecuteAction(
() =>
{
using (var transactionScope = new TransactionScope(...))
{
invocation.Proceed();
transactionScope.Complete();
}
});
}
}
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