Exponential backoff is a standard error handling
strategy for network applications in which a client periodically retries a
failed request with increasing delays between requests. Clients should use
exponential backoff for all requests to Memorystore for Valkey that return
HTTP 5xx
and 429
response code errors.
Understanding how exponential backoff works is important if you are building client applications that use the Memorystore for Valkey REST API directly.
If you are using the Google Cloud console, the console sends requests to Memorystore for Valkey on your behalf and handles any necessary backoff.
Example algorithm
An exponential backoff algorithm retries requests by exponentially increasing the wait time between retries up to a maximum backoff time. An example is:
Make a request to Memorystore for Valkey.
If the request fails, wait 1 +
random_number_milliseconds
seconds and retry the request.If the request fails, wait 2 +
random_number_milliseconds
seconds and retry the request.If the request fails, wait 4 +
random_number_milliseconds
seconds and retry the request.And so on, up to a
maximum_backoff
time.Continue waiting and retrying up to some maximum number of retries, but do not increase the wait period between retries.
where:
The wait time is min(((2^
n
)+random_number_milliseconds
),maximum_backoff
), withn
incremented by 1 for each iteration (request).random_number_milliseconds
is a random number of milliseconds less than or equal to 1000. This helps to avoid cases where many clients get synchronized by some situation and all retry at once, sending requests in synchronized waves. The value ofrandom_number_milliseconds
should be recalculated after each retry request.maximum_backoff
is typically 32 or 64 seconds. The appropriate value depends on the use case.
It's okay to continue retrying once you reach the maximum_backoff
time.
Retries after this point do not need to continue increasing backoff time. For
example, if a client uses an maximum_backoff
time of 64 seconds, then after
reaching this value, the client can retry every 64 seconds. At some point,
clients should be prevented from retrying infinitely.
The maximum backoff and maximum number of retries that a client uses depends on the use case and network conditions. For example, mobile clients of an application may need to retry more times and for longer intervals when compared to desktop clients of the same application.
If the retry requests fail after exceeding the maximum number of retries, report or log an error using one of the methods listed under Getting support.