I am querying a DynamoDB table from Lambda using java SDK and after a certain amount of time (5-10 minutes) the next query is VERY slow - in the order of 5s. Dong the same query again shortly after that, is super fast (milliseconds), but after a lengthy delay there seems to be some kind of coldstart.
Below is the Logs from cloudwatch: The Dynamodb query occured between these 2 log statements
Then if I run again shortly afterwards:
Can anyone tell me what I am missing here please?
There are a few things at play here:
Lambda cold start refers to the delay when an AWS Lambda function is invoked after idleness. It involves resource allocation, runtime initialization, and code loading. Factors affecting duration include function complexity and dependencies. To address this, you can optimize code, use provisioned concurrency, or implement warming techniques for more responsive applications.
With every newly loaded Lambda container, the initiation of a TLS connection becomes necessary. This process can lead to notable latency, especially in scenarios where responses are typically expected in milliseconds.
Moreover, similar to Lambda, DynamoDB experiences a phenomenon akin to a cold start. DynamoDB leverages cached metadata, including partition details for efficient data retrieval, authentication, authorization information, and other internal metadata. This caching mechanism is crucial for ensuring the efficient operation of the system.
When Lambda requests are infrequent, options for mitigating DynamoDB cold start and TLS connection challenges are limited. However, as discussed in the Lambda section, efforts to minimize Lambda cold starts can have a positive ripple effect, potentially contributing to a reduction in DynamoDB latency as well.