history - Understanding of Ps. 137 before the exile

Psalm 137 starts (in my own translation)

On Babylon's rivers, there, we sat, also cried, in our remembering Zion.

and continues to describe the scene. Ibn Ezra cites some who hold that David authored the psalm with divine inspiration and was referring to the Babylonian exile, which was more than 400 years after his passing; the (later) M'tzudas David also holds of this view. (An alternative view is cited by ibn Ezra there, but for the purposes of this question assume David wrote it referring to later events.)

My question is how people (average Joes, not, say, David) of David's time and the 400-odd years thereafter understood the psalm. Did they know it referred to an impending Babylonian exile, just not know when it would be? Did they think it was metaphoric, referring to other things entirely? Did they think it was referring to a Babylonian exile, but one which (they thought) had been averted? Did they look at it and not have any idea what it meant? Or what?

A sourced answer would be ideal.

Answer

I heard that Malbim discusses this issue. While he holds you can say that it was written at the time of the Churban, he also discusses how it could have been written by David. He raises two issues:

1. What would people have thought about such a mizmor before the churban?



2. What would happen to the mizmor if they did teshuvah and there was no churban?

He answers that David could have written it as a secret scroll that was passed down without being publicized. After the churban, the scroll was publicized and became part of tehillim. This avoids the "strangeness" of people reading such a mizmor during the time of e.g. Solomon.