git.postgresql.org Git - postgresql.git/commitdiff

git projects / postgresql.git / commitdiff

Sat, 4 Feb 2023 22:40:35 +0000 (17:40 -0500)

deconstruct_distribute tweaks the outer join scope (ojscope)
it passes to distribute_qual_to_rels when considering an outer
join qual that's above potentially-commutable outer joins.
However, if the current join is *not* potentially commutable,
we shouldn't do that. The argument that distribute_qual_to_rels
will not do something wrong with the bogus ojscope falls flat
if we don't pass it non-null postponed_oj_qual_list. Moreover,
there's no need to play games in this case since we aren't going
to commute anything.

Per SQLSmith testing by Robins Tharakan.

Discussion: https://postgr.es/m/CAEP4nAw74k4b-=93gmfCNX3MOY3y4uPxqbk_MnCVEpdsqHJVsg@mail.gmail.com

src/backend/optimizer/plan/initsplan.c patch | blob | blame | history

src/test/regress/expected/join.out patch | blob | blame | history

src/test/regress/sql/join.sql patch | blob | blame | history

diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c

index a19260f9bc4b009b174783b366ab28d6c4b39407..c301e6dffc41f60c9d7e77ef853c7ed0aa155fa4 100644 (file)

--- a/src/backend/optimizer/plan/initsplan.c

+++ b/src/backend/optimizer/plan/initsplan.c

@@ -1189,23 +1189,8 @@ deconstruct_distribute(PlannerInfo *root, JoinTreeItem *jtitem)

if (j->jointype == JOIN_SEMI)

ojscope = NULL;

else

- {

ojscope = bms_union(sjinfo->min_lefthand,

sjinfo->min_righthand);

- /*

- * Add back any commutable lower OJ relids that were removed

- * from min_lefthand or min_righthand, else the ojscope

- * cross-check in distribute_qual_to_rels will complain. If

- * any such OJs were removed, we will postpone processing of

- * non-degenerate clauses, so this addition doesn't affect

- * anything except that cross-check and some Asserts. Real

- * clause positioning decisions will be made later, when we

- * revisit the postponed clauses.

- */

- if (sjinfo->commute_below)

- ojscope = bms_add_members(ojscope, sjinfo->commute_below);

- }

}

else

{

@@ -1221,7 +1206,21 @@ deconstruct_distribute(PlannerInfo *root, JoinTreeItem *jtitem)

* they will drop down below this join anyway.)

if (j->jointype == JOIN_LEFT && sjinfo->lhs_strict)

+ {

postponed_oj_qual_list = &jtitem->oj_joinclauses;

+ /*

+ * Add back any commutable lower OJ relids that were removed from

+ * min_lefthand or min_righthand, else the ojscope cross-check in

+ * distribute_qual_to_rels will complain. Since we are postponing

+ * processing of non-degenerate clauses, this addition doesn't

+ * affect anything except that cross-check. Real clause

+ * positioning decisions will be made later, when we revisit the

+ * postponed clauses.

+ */

+ if (sjinfo->commute_below)

+ ojscope = bms_add_members(ojscope, sjinfo->commute_below);

+ }

else

postponed_oj_qual_list = NULL;

diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out

index c520839bf7d7b961caa60709ac68fa23faaec0a1..9762952efd21dc76c8ae7700300d74a0a3eb8fd2 100644 (file)

--- a/src/test/regress/expected/join.out

+++ b/src/test/regress/expected/join.out

@@ -4451,6 +4451,24 @@ select * from

doh! | 123 | 456 | hi de ho neighbor |

(2 rows)

+-- check handling of a variable-free qual for a non-commutable outer join

+explain (costs off)

+select nspname

+from (select 1 as x) ss1

+left join

+( select n.nspname, c.relname

+ from pg_class c left join pg_namespace n on n.oid = c.relnamespace

+ where c.relkind = 'r'

+) ss2 on false;

+ QUERY PLAN

+--------------------------------

+ Nested Loop Left Join

+ Join Filter: false

+ -> Result

+ One-Time Filter: false

+(5 rows)

-- test for appropriate join order in the presence of lateral references

diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql

index b0e8d559cdb7c895da5fabff87910bd25c231901..3ef29960409541405e7c353ab0d3fe86590ce6b2 100644 (file)

--- a/src/test/regress/sql/join.sql

+++ b/src/test/regress/sql/join.sql

@@ -1535,6 +1535,16 @@ select * from

left join int4_tbl i4

on i8.q1 = i4.f1;

+-- check handling of a variable-free qual for a non-commutable outer join

+explain (costs off)

+select nspname

+from (select 1 as x) ss1

+left join

+( select n.nspname, c.relname

+ from pg_class c left join pg_namespace n on n.oid = c.relnamespace

+ where c.relkind = 'r'

+) ss2 on false;

-- test for appropriate join order in the presence of lateral references

This is the main PostgreSQL git repository.

RSS Atom