Returns a policy that retries a specified number of times with a randomized exponential backoff scheme, using default values for the minimum and maximum backoff. Namespace: Microsoft.WindowsAzure.StorageClient
Assembly: Microsoft.WindowsAzure.StorageClient (in Microsoft.WindowsAzure.StorageClient.dll)
Usage
| Visual Basic |
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Dim retryCount As Integer Dim deltaBackoff As TimeSpan Dim returnValue As RetryPolicy returnValue = RetryPolicies.RetryExponential(retryCount, deltaBackoff) |
Syntax
| Visual Basic |
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Public Shared Function RetryExponential ( _ retryCount As Integer, _ deltaBackoff As TimeSpan _ ) As RetryPolicy |
| C# |
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public static RetryPolicy RetryExponential ( int retryCount, TimeSpan deltaBackoff ) |
| C++ |
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public: static RetryPolicy^ RetryExponential ( int retryCount, TimeSpan deltaBackoff ) |
| J# |
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| JScript |
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Parameters
- retryCount
Type: System.Int32
A non-negative number indicating the number of times to retry.
- deltaBackoff
Type: System.TimeSpan
The delta backoff value used by the exponential backoff retry policy.
Return Value
Type: Microsoft.WindowsAzure.StorageClient.RetryPolicyThe retry policy.Remarks
The retry policy returned by RetryExponential performs an exponential backoff using default values for the minimum backoff and the maximum backoff. The default values are defined by the DefaultMinBackoff and DefaultMaxBackoff constants.
This method provides the default retry policy for the CloudBlobClient, CloudQueueClient, and CloudTableClient objects. The default retry policy for the service client objects is set by calling RetryExponential to return a retry policy delegate that passes the DefaultClientRetryCount to specify the number of times to retry, and the DefaultClientBackoff constant to calculate the increment for the backoff interval.
The RetryExponential method returns a RetryPolicy delegate that returns a ShouldRetry delegate. The ShouldRetry delegate uses the algorithm shown here:
| Copy Code | |
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public static RetryPolicy RetryExponential(int retryCount, TimeSpan deltaBackoff)
{
//Returns a RetryPolicy delegate.
return () =>
{
//Returns a ShouldRetry delegate.
return (int currentRetryCount, Exception lastException, out TimeSpan retryInterval) =>
{
if (currentRetryCount < retryCount)
{
Random rand = new Random();
int increment = (int)((Math.Pow(2, currentRetryCount) - 1) * rand.Next((int)(deltaBackoff.TotalMilliseconds * 0.8), (int)(deltaBackoff.TotalMilliseconds * 1.2)));
int timeToSleepMsec = (int)Math.Min(RetryPolicies.DefaultMinBackoff.TotalMilliseconds + increment, RetryPolicies.DefaultMaxBackoff.TotalMilliseconds);
retryInterval = TimeSpan.FromMilliseconds(timeToSleepMsec);
return true;
}
retryInterval = TimeSpan.Zero;
return false;
};
};
}
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