Re: ERROR: wrong varnullingrels (b 3) (expected (b)) for Var 2/1
| От | Richard Guo |
|---|---|
| Тема | Re: ERROR: wrong varnullingrels (b 3) (expected (b)) for Var 2/1 |
| Дата | |
| Msg-id | CAMbWs49ANAiHiApMNamW7e6saiha3GVj81RdDEpEZaFO9Gzxqw@mail.gmail.com обсуждение исходный текст |
| Ответ на | ERROR: wrong varnullingrels (b 3) (expected (b)) for Var 2/1 (Markus Winand <markus.winand@winand.at>) |
| Ответы |
Re: ERROR: wrong varnullingrels (b 3) (expected (b)) for Var 2/1
|
| Список | pgsql-hackers |
On Tue, May 30, 2023 at 10:48 PM Markus Winand <markus.winand@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
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
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