[skybrian]

This seems pretty simple when events are logged as they happen with little or no latency and you can let the stream set the timestamp. I wonder, though, about the case where events may be buffered, perhaps due to an unreliable network? The time that the event occurred might be significantly earlier than the time it's inserted, and furthermore events are arriving out of order. It seems like things get much more complicated?

Let's say tennis games are recorded on a piece of paper and entered into the computer later. What is different?

[antirez]

Two solutions: 1. add a timestamp as a field, and just use the ID, but in that case range queries are going to be a problem. 2. exactly because of what you stated, XADD will soon have a special argument to say: I'm going to insert an element in the middle: this is the time in milliseconds (find for me the counter part if I did not specify one). Could be confusing for streaming, but as a data structure to insert in the middle is spot-on and there is nothing preventing that.