Retry.md

Retry

• Motivation
• Solution
  • Concepts
  • Implementation
    • Retry Strategies
    • Retry Policies
    • Advice
• Pros & Cons
  • Pros
  • Cons
• Consideration
• When To Use
• References

Motivation

Solution

Concepts

• Retry an operation for transient faults.

Implementation

Retry Strategies

Strategy Name	Situation	Operation
Cancel	The failure isn't transient or is unlikely to be successful if repeated.	Cancel the operation and report an exception.
Retry	The failure is unlikely to be repeated.	Retry the failing request again immediately.
Retry after delay	The failure is unlikely to be repeated after a short period of time.	Wait for a suitable time before retrying the request.

Retry Policies

• The time between retries should be specified.
  • fixed time
  • increasing time
• The maximum number of retries should be specified.

Advice

• For some noncritical operations, it's better to fail fast rather than retry several times and impact the throughput of the application.
• It's useful for the retry policy to adjust the time between retry attempts based on the type of the exception.

Pros & Cons

Pros

Cons

Consideration

Topic	Consideration	Possible Solution Options
Duplicate execution	Retries could cause the operation to be executed more than once, with unintended side effects.	Consider to make the operation idempotent (If the operation is idempotent, it would be inherently safe to retry).

When To Use

References

• Web Article: Retry pattern | https://docs.microsoft.com/en-us/azure/architecture/patterns/retry