On Tue, May 30, 2023 at 10:48 PM Markus Winand <markus.win...@winand.at> wrote:
> I found an error similar to others before ([1]) that is still persists as > of head right now (0bcb3ca3b9). > > CREATE TABLE t ( > n INTEGER > ); > > SELECT * > FROM (VALUES (1)) t(c) > LEFT JOIN t ljl1 ON true > LEFT JOIN LATERAL (WITH cte AS (SELECT * FROM t WHERE t.n = ljl1.n) > SELECT * FROM cte) ljl2 ON ljl1.n = 1; > > ERROR: wrong varnullingrels (b 3) (expected (b)) for Var 2/1 > > Note that the error does **not** occur if the CTE is unwrapped like this: > > SELECT * > FROM (VALUES (1)) t(c) > LEFT JOIN t ljl1 ON true > LEFT JOIN LATERAL (SELECT * FROM t WHERE t.n = ljl1.n) ljl2 ON ljl1.n = > 1; Thanks for the report! Reproduced here. Also it can be reproduced with subquery, as long as the subquery is not pulled up. SELECT * FROM (VALUES (1)) t(c) LEFT JOIN t ljl1 ON true LEFT JOIN LATERAL (SELECT * FROM t WHERE t.n = ljl1.n offset 0) ljl2 ON ljl1.n = 1; ERROR: wrong varnullingrels (b 3) (expected (b)) for Var 2/1 When we transform the first form of identity 3 to the second form, we've converted Pb*c to Pbc in deconstruct_distribute_oj_quals. But we neglect to consider that rel C might be a RTE_SUBQUERY and contains quals that have lateral references to B. So the B vars in such quals have wrong nulling bitmaps and we'd finally notice that when we do fix_upper_expr for the NestLoopParam expressions. Thanks Richard
