The patch looks simple and straightforward but I question the wisdom of allowing anything else but "abort" in the case of an SqlException. You can't simply continue and read the next row of the query when this happens. My thinking is "onAbort" is more for handling whole text documents that for some reason don't parse correctly.
I guess if it was a child entity doing n+1 selects it could just go do the next select with the following document. Perhaps if the parent entity sometimes passes it a wrongly-typed join value this would happen and it would be ok to go on, assuming the next doc would have a correct join value? But then again, you could just craft your sql to handle this contingency in these cases.
So if Sascha, Alexander or anyone can explain better why this is a good idea, and possibly contribute a unit test then perhaps we can commit this. Otherwise I think its a "won't fix".