> Since the CTE has FOR UPDATE, it blocks and returns the updated-by-S1
> version of the row. But the outer query initially reads the old
> version of the row, so the join condition fails, and we never get
> to the lock-row-and-recheck behavior of UPDATE.
I see, thanks.
> I am not sure what you are hoping to accomplish with that self-join.
> I suppose this is an oversimplified example, but it's too
> oversimplified for anyone to see why you'd want to do it like that.
I was original trying to build a generic way for fetching old rows in
UPDATE RETURNING clause for pre-18 versions but the self join does
not work well with concurrent updates either resulting in lost updates
or not returning the concurrently updated value in RETURNING.
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Thanks,
Tanzeel
