Re: Use LIMIT instead of Unique for DISTINCT when all distinct pathkeys are redundant

 

I find the duplicate "Limit" node is not that concerning after I realize
it may appear in other queries, such as

explain (analyze, timing off, costs off)
select * from (select * from (select * from generate_series(1,100)i limit 10) limit 5) limit 1;
                                  QUERY PLAN
------------------------------------------------------------------------------
 Limit (actual rows=1 loops=1)
   ->  Limit (actual rows=1 loops=1)
         ->  Limit (actual rows=1 loops=1)
               ->  Function Scan on generate_series i (actual rows=1 loops=1)

Although the situation is different in that the Limit node is actually
atop SubqueryScan which is removed afterwards, but the final plan
appears as a Limit node atop another Limit node.

So I wonder maybe we can just live with it, or resolve it in a separate
patch.

Thanks
Richard