Final answer:
Short polling in Amazon SQS is when a service checks for message availability and immediately returns a response, potentially leading to more network traffic and costs with empty responses, but allowing real-time processing.
Step-by-step explanation:
Short polling in Amazon Simple Queue Service (SQS) is a process where a server repeatedly checks if there are any messages available in the queue to process. When the consumer of the messages makes a request to SQS to receive messages, SQS immediately returns a response, even if the queue is empty, meaning it doesn't wait on the server for messages to arrive.
The response might contain anywhere from zero to several messages that you can process. If more messages are available, you need to make additional requests to retrieve them. This differs from long polling, where the server holds the request open for a specified period until a message arrives in the queue or the timeout is reached.
Short polling tends to be less efficient than long polling because it often returns empty responses, leading to unnecessary network traffic and higher costs if the queue is not very active. On the other hand, it offers nearly real-time message processing capabilities, which might be a requirement for certain applications.