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Rename EXISTS-to-ANY converted subplan to exists_to_any

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Simple EXISTS subplans can be converted to hashed ANY subplans as
an alternative implementation. Previously, both the original EXISTS
subplan and the converted ANY subplan used names with the
exists_ prefix, making EXPLAIN output harder to read and
pg_plan_advice targets less clear.

Use the exists_to_any_ prefix for converted ANY subplans so that
their names distinguish them from the original EXISTS alternative.
This only changes the names shown by EXPLAIN and used by plan advice;
it does not affect planner behavior.

Author: Yugo Nagata <nagata@sraoss.co.jp>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: solai v <solai.cdac@gmail.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/20260605165641.3950f99ace0aad8f807abe96@sraoss.co.jp
Backpatch-through: 19
This commit is contained in:
Fujii Masao
2026-08-15 18:12:14 +09:00
parent 7e6e294e4e
commit 7b7c4a8dcc
5 changed files with 35 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
contrib/pg_plan_advice/expected/alternatives.out
View File

@@ -12,15 +12,15 @@ VACUUM ANALYZE alt_t2;
EXPLAIN (COSTS OFF, PLAN_ADVICE)
SELECT * FROM alt_t1
WHERE EXISTS (SELECT 1 FROM alt_t2 WHERE alt_t2.a = alt_t1.a) OR alt_t1.a < 0;
QUERY PLAN
-------------------------------------------------------------------
QUERY PLAN
--------------------------------------------------------------------------
Seq Scan on alt_t1
Filter: ((ANY (a = (hashed SubPlan exists_2).col1)) OR (a < 0))
SubPlan exists_2
Filter: ((ANY (a = (hashed SubPlan exists_to_any_1).col1)) OR (a < 0))
SubPlan exists_to_any_1
-> Seq Scan on alt_t2
Generated Plan Advice:
SEQ_SCAN(alt_t1 alt_t2@exists_2)
NO_GATHER(alt_t1 alt_t2@exists_2)
SEQ_SCAN(alt_t1 alt_t2@exists_to_any_1)
NO_GATHER(alt_t1 alt_t2@exists_to_any_1)
DO_NOT_SCAN(alt_t2@exists_1)
(8 rows)
@@ -31,21 +31,21 @@ SET LOCAL pg_plan_advice.advice = 'DO_NOT_SCAN(alt_t2@exists_1)';
EXPLAIN (COSTS OFF, PLAN_ADVICE)
SELECT * FROM alt_t1
WHERE EXISTS (SELECT 1 FROM alt_t2 WHERE alt_t2.a = alt_t1.a) OR alt_t1.a < 0;
QUERY PLAN
-------------------------------------------------------------------
QUERY PLAN
--------------------------------------------------------------------------
Seq Scan on alt_t1
Filter: ((ANY (a = (hashed SubPlan exists_2).col1)) OR (a < 0))
SubPlan exists_2
Filter: ((ANY (a = (hashed SubPlan exists_to_any_1).col1)) OR (a < 0))
SubPlan exists_to_any_1
-> Seq Scan on alt_t2
Supplied Plan Advice:
DO_NOT_SCAN(alt_t2@exists_1) /* matched */
Generated Plan Advice:
SEQ_SCAN(alt_t1 alt_t2@exists_2)
NO_GATHER(alt_t1 alt_t2@exists_2)
SEQ_SCAN(alt_t1 alt_t2@exists_to_any_1)
NO_GATHER(alt_t1 alt_t2@exists_to_any_1)
DO_NOT_SCAN(alt_t2@exists_1)
(10 rows)
SET LOCAL pg_plan_advice.advice = 'DO_NOT_SCAN(alt_t2@exists_2)';
SET LOCAL pg_plan_advice.advice = 'DO_NOT_SCAN(alt_t2@exists_to_any_1)';
EXPLAIN (COSTS OFF, PLAN_ADVICE)
SELECT * FROM alt_t1
WHERE EXISTS (SELECT 1 FROM alt_t2 WHERE alt_t2.a = alt_t1.a) OR alt_t1.a < 0;
@@ -57,12 +57,12 @@ WHERE EXISTS (SELECT 1 FROM alt_t2 WHERE alt_t2.a = alt_t1.a) OR alt_t1.a < 0;
-> Index Only Scan using alt_t2_a_idx on alt_t2
Index Cond: (a = alt_t1.a)
Supplied Plan Advice:
DO_NOT_SCAN(alt_t2@exists_2) /* matched */
DO_NOT_SCAN(alt_t2@exists_to_any_1) /* matched */
Generated Plan Advice:
SEQ_SCAN(alt_t1)
INDEX_ONLY_SCAN(alt_t2@exists_1 public.alt_t2_a_idx)
NO_GATHER(alt_t1 alt_t2@exists_1)
DO_NOT_SCAN(alt_t2@exists_2)
DO_NOT_SCAN(alt_t2@exists_to_any_1)
(12 rows)
COMMIT;

2
contrib/pg_plan_advice/sql/alternatives.sql
View File

@@ -22,7 +22,7 @@ SET LOCAL pg_plan_advice.advice = 'DO_NOT_SCAN(alt_t2@exists_1)';
EXPLAIN (COSTS OFF, PLAN_ADVICE)
SELECT * FROM alt_t1
WHERE EXISTS (SELECT 1 FROM alt_t2 WHERE alt_t2.a = alt_t1.a) OR alt_t1.a < 0;
SET LOCAL pg_plan_advice.advice = 'DO_NOT_SCAN(alt_t2@exists_2)';
SET LOCAL pg_plan_advice.advice = 'DO_NOT_SCAN(alt_t2@exists_to_any_1)';
EXPLAIN (COSTS OFF, PLAN_ADVICE)
SELECT * FROM alt_t1
WHERE EXISTS (SELECT 1 FROM alt_t2 WHERE alt_t2.a = alt_t1.a) OR alt_t1.a < 0;

8
src/backend/optimizer/plan/subselect.c
View File

@@ -271,8 +271,12 @@ make_subplan(PlannerInfo *root, Query *orig_subquery,
{
char *plan_name;
/* Generate Paths for the ANY subquery; we'll need all rows */
plan_name = choose_plan_name(root->glob, sublinkstr, true);
/*
* Generate Paths for the ANY subquery; we'll need all rows.
* Use a distinct prefix for this user-visible name, since this is
* an ANY implementation of the original EXISTS subplan.
*/
plan_name = choose_plan_name(root->glob, "exists_to_any", true);
subroot = subquery_planner(root->glob, subquery, plan_name,
root, subroot, false, 0.0, NULL);

10
src/test/regress/expected/partition_prune.out
View File

@@ -1967,15 +1967,15 @@ where asptab.id > ss.b::int;
-> Seq Scan on int4_tbl touter
-> Append
-> Index Only Scan using asptab0_pkey on asptab0 asptab_1
Index Cond: (id > (EXISTS(SubPlan exists_3))::integer)
SubPlan exists_4
Index Cond: (id > (EXISTS(SubPlan exists_2))::integer)
SubPlan exists_to_any_2
-> Seq Scan on int4_tbl tinner_2
-> Index Only Scan using asptab1_pkey on asptab1 asptab_2
Index Cond: (id > (EXISTS(SubPlan exists_3))::integer)
SubPlan exists_3
Index Cond: (id > (EXISTS(SubPlan exists_2))::integer)
SubPlan exists_2
-> Seq Scan on int4_tbl tinner_1
Filter: (f1 = touter.f1)
SubPlan exists_2
SubPlan exists_to_any_1
-> Seq Scan on int4_tbl tinner
(14 rows)

16
src/test/regress/expected/subselect.out
View File

@@ -1253,12 +1253,12 @@ rollback; -- to get rid of the bogus operator
explain (costs off)
select count(*) from tenk1 t
where (exists(select 1 from tenk1 k where k.unique1 = t.unique2) or ten < 0);
QUERY PLAN
---------------------------------------------------------------------------------
QUERY PLAN
----------------------------------------------------------------------------------------
Aggregate
-> Seq Scan on tenk1 t
Filter: ((ANY (unique2 = (hashed SubPlan exists_2).col1)) OR (ten < 0))
SubPlan exists_2
Filter: ((ANY (unique2 = (hashed SubPlan exists_to_any_1).col1)) OR (ten < 0))
SubPlan exists_to_any_1
-> Index Only Scan using tenk1_unique1 on tenk1 k
(5 rows)
@@ -1303,8 +1303,8 @@ analyze exists_tbl;
explain (costs off)
select * from exists_tbl t1
where (exists(select 1 from exists_tbl t2 where t1.c1 = t2.c2) or c3 < 0);
QUERY PLAN
---------------------------------------------------------------------------
QUERY PLAN
----------------------------------------------------------------------------------
Append
-> Seq Scan on exists_tbl_null t1_1
Filter: (EXISTS(SubPlan exists_1) OR (c3 < 0))
@@ -1315,8 +1315,8 @@ select * from exists_tbl t1
-> Seq Scan on exists_tbl_def t2_2
Filter: (t1_1.c1 = c2)
-> Seq Scan on exists_tbl_def t1_2
Filter: ((ANY (c1 = (hashed SubPlan exists_2).col1)) OR (c3 < 0))
SubPlan exists_2
Filter: ((ANY (c1 = (hashed SubPlan exists_to_any_1).col1)) OR (c3 < 0))
SubPlan exists_to_any_1
-> Append
-> Seq Scan on exists_tbl_null t2_4
-> Seq Scan on exists_tbl_def t2_5