Re: BUG #18170: Unexpected error: no relation entry for relid 3
| От | Richard Guo |
|---|---|
| Тема | Re: BUG #18170: Unexpected error: no relation entry for relid 3 |
| Дата | |
| Msg-id | CAMbWs494m3AjhHry_HFCFi_SJ+6-PaeMRbx7jK39ZHmK0MVOUA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: BUG #18170: Unexpected error: no relation entry for relid 3 (Andrei Lepikhov <a.lepikhov@postgrespro.ru>) |
| Ответы |
Re: BUG #18170: Unexpected error: no relation entry for relid 3
Re: BUG #18170: Unexpected error: no relation entry for relid 3 |
| Список | pgsql-bugs |
On Fri, Oct 27, 2023 at 7:00 PM Andrei Lepikhov <a.lepikhov@postgrespro.ru> wrote:
So, I can propose two options. First - don't clean only the current root
structure, but also make cleanup of the parent. Although it looks safe,
I am not happy with this approach - it seems too simple: we should have
a genuine reason for such a cleaning because it potentially adds overhead.
The second option is to add a flag for not altering queries in
remove_nulling_relids() - it looks like a mistake when we have two
different query trees in the root and its parent. Also, it reduces
memory usage a bit.
So, if my analysis is correct, it is better to use the second way (see
attachment).
Alternatively, can we look at subroot->parse->targetList instead of
subquery->targetList where we call estimate_num_groups on the output of
the subquery?
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/src/backend/optimizer/prep/prepunion.c
@@ -341,7 +341,7 @@ recurse_set_operations(Node *setOp, PlannerInfo *root,
*pNumGroups = subpath->rows;
else
*pNumGroups = estimate_num_groups(subroot,
- get_tlist_exprs(subquery->targetList, false),
+ get_tlist_exprs(subroot->parse->targetList, false),
subpath->rows,
NULL,
NULL);
BTW, I'm a little surprised that QTW_DONT_COPY_QUERY doesn't seem to be
used anywhere currently.
Thanks
Richard
subquery->targetList where we call estimate_num_groups on the output of
the subquery?
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/src/backend/optimizer/prep/prepunion.c
@@ -341,7 +341,7 @@ recurse_set_operations(Node *setOp, PlannerInfo *root,
*pNumGroups = subpath->rows;
else
*pNumGroups = estimate_num_groups(subroot,
- get_tlist_exprs(subquery->targetList, false),
+ get_tlist_exprs(subroot->parse->targetList, false),
subpath->rows,
NULL,
NULL);
BTW, I'm a little surprised that QTW_DONT_COPY_QUERY doesn't seem to be
used anywhere currently.
Thanks
Richard
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