For all the synchronous invocations (1 and 3), the number of invocations depends on the client. If the client invokes the function once, the function will run exactly once.
For asynchronous invocations (2 and 4), events are added to an internal queue and the functions will run at least once.
For polling use cases (5 and 6, but also Kinesis Data streams, DynamoDB streams, MSK and MQ), the invocation is actually synchronous, however, SQS may deliver a message more than once, so the function may run more than once. With FIFO, messages are delivered exactly once, but due to function errors, we may invoke the function more than once. Same for the other cases.
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