database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-12-21 05:21:08 +03:00
Code Activity

Don't generate fake "*SELECT*" or "*SELECT* %d" subquery aliases.

Browse Source 
rte->alias should point only to a user-written alias, but in these
cases that principle was violated. Fixing this causes some regression
test output changes: wherever rte->alias previously had a value and
is now NULL, rte->eref is now set to a generated name rather than to
rte->alias; and the scheme used to generate eref names differs from
what we were doing for aliases.

The upshot is that instead of "*SELECT*" or "*SELECT* %d",
EXPLAIN will now emit "unnamed_subquery" or "unnamed_subquery_%d".
But that's a reasonable descriptor, and we were already producing
that in yet other cases, so this seems not too objectionable.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Co-authored-by: Robert Haas <rhaas@postgresql.org>
Discussion: https://postgr.es/m/CA+TgmoYSYmDA2GvanzPMci084n+mVucv0bJ0HPbs6uhmMN6HMg@mail.gmail.com
This commit is contained in:
Robert Haas
2025-09-08 11:50:33 -04:00
parent 3399c26554
commit 585e31fcb6
6 changed files with 20 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/test/regress/expected/partition_prune.out
View File

@@ -4763,7 +4763,7 @@ select min(a) over (partition by a order by a) from part_abc where a >= stable_o
QUERY PLAN
----------------------------------------------------------------------------------------------
Append
-> Subquery Scan on "*SELECT* 1_1"
-> Subquery Scan on unnamed_subquery_2
-> WindowAgg
Window: w1 AS (PARTITION BY part_abc.a ORDER BY part_abc.a)
-> Append
@@ -4780,7 +4780,7 @@ select min(a) over (partition by a order by a) from part_abc where a >= stable_o
-> Index Scan using part_abc_3_2_a_idx on part_abc_3_2 part_abc_4
Index Cond: (a >= (stable_one() + 1))
Filter: (d <= stable_one())
-> Subquery Scan on "*SELECT* 2"
-> Subquery Scan on unnamed_subquery_1
-> WindowAgg
Window: w1 AS (PARTITION BY part_abc_5.a ORDER BY part_abc_5.a)
-> Append

8
src/test/regress/expected/rangefuncs.out
View File

@@ -2130,10 +2130,10 @@ select testrngfunc();
explain (verbose, costs off)
select * from testrngfunc();
QUERY PLAN
----------------------------------------------------------
Subquery Scan on "*SELECT*"
Output: "*SELECT*"."?column?", "*SELECT*"."?column?_1"
QUERY PLAN
----------------------------------------------------------------------
Subquery Scan on unnamed_subquery
Output: unnamed_subquery."?column?", unnamed_subquery."?column?_1"
-> Unique
Output: (1), (2)
-> Sort

14
src/test/regress/expected/union.out
View File

@@ -942,7 +942,7 @@ SELECT q1 FROM int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1;
ERROR: column "q2" does not exist
LINE 1: ... int8_tbl EXCEPT SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1...
^
DETAIL: There is a column named "q2" in table "*SELECT* 2", but it cannot be referenced from this part of the query.
DETAIL: There is a column named "q2" in table "unnamed_subquery", but it cannot be referenced from this part of the query.
-- But this should work:
SELECT q1 FROM int8_tbl EXCEPT (((SELECT q2 FROM int8_tbl ORDER BY q2 LIMIT 1))) ORDER BY 1;
q1
@@ -1338,14 +1338,14 @@ where q2 = q2;
----------------------------------------------------------
Unique
-> Merge Append
Sort Key: "*SELECT* 1".q1
-> Subquery Scan on "*SELECT* 1"
Sort Key: unnamed_subquery.q1
-> Subquery Scan on unnamed_subquery
-> Unique
-> Sort
Sort Key: i81.q1, i81.q2
-> Seq Scan on int8_tbl i81
Filter: (q2 IS NOT NULL)
-> Subquery Scan on "*SELECT* 2"
-> Subquery Scan on unnamed_subquery_1
-> Unique
-> Sort
Sort Key: i82.q1, i82.q2
@@ -1374,14 +1374,14 @@ where -q1 = q2;
--------------------------------------------------------
Unique
-> Merge Append
Sort Key: "*SELECT* 1".q1
-> Subquery Scan on "*SELECT* 1"
Sort Key: unnamed_subquery.q1
-> Subquery Scan on unnamed_subquery
-> Unique
-> Sort
Sort Key: i81.q1, i81.q2
-> Seq Scan on int8_tbl i81
Filter: ((- q1) = q2)
-> Subquery Scan on "*SELECT* 2"
-> Subquery Scan on unnamed_subquery_1
-> Unique
-> Sort
Sort Key: i82.q1, i82.q2