This question was posted here "It's a long time that" – correct or not? a few months back and an answer was selected. The answer given is hardly satisfying, and I feel that the question is worth exploring in more detail.
The OP states that a native speaker corrected him and said he should write "It's been a long time since."
In looking at some of the hits that the OP posted it is apparent that the phrase "It's a long time that" can be used in several ways. This was from a native English source:
When you sprain both your ankles, you have to do what you think is right. As I said, if he's healthy, he should play. If he's injured, he should sit. It's a long time that he's been off. He's got to go.
To me, this is ok. He's talking about the amount of time-off the player has taken. He's not talking about the last time he took some time-off…a present perfect idea.
The answer that was selected uses this as a reference Try as I might, I can't understand what the good doctor is saying.
Also, in looking at the OP's question it occurs to me that they might be using the phrase in the sense of the NBA example I provided above, in other words, he is talking about the amount of time spent. To me, a better way to express this would be "I've been doing this for a long time," or "I spent a long time on that," or maybe "I did that for a long time." but maybe I'm changing the meaning.
My question is: Is the example from google books an archaic way of using the present perfect? There's no present perfect in the example. Also, is the sentence "It's a long time that I did that." grammatically correct, and if not, why not?
Best Answer
[I'm reposting the earlier comment by Janus Bahs Jacquet as an answer, as this seems a better option than having this question linger unanswered yet undeleted (and it doesn't deserve to be closed)...]
The example you quote here works fine for me too, but it’s fundamentally different from the one in Emanuel’s question. It’s basically a cleft version of “He’s been off (for) a long time”. If that is indeed the meaning that Emanuel was trying to get through, then he shouldn’t have been using the present tense of the cleaving verb with the simple past of the underlying matrix verb: “It was a long time that I did this” could work for “I did this (for) a long time”, but not “It’s a long time that I did this”. At least not to me.