From ab5fcf2b04f9cc4ecccb1832faabadb047087d23 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 22 Feb 2019 12:23:00 -0500 Subject: [PATCH] Fix plan created for inherited UPDATE/DELETE with all tables excluded. In the case where inheritance_planner() finds that every table has been excluded by constraints, it thought it could get away with making a plan consisting of just a dummy Result node. While certainly there's no updating or deleting to be done, this had two user-visible problems: the plan did not report the correct set of output columns when a RETURNING clause was present, and if there were any statement-level triggers that should be fired, it didn't fire them. Hence, rather than only generating the dummy Result, we need to stick a valid ModifyTable node on top, which requires a tad more effort here. It's been broken this way for as long as inheritance_planner() has known about deleting excluded subplans at all (cf commit 635d42e9c), so back-patch to all supported branches. Amit Langote and Tom Lane, per a report from Petr Fedorov. Discussion: https://postgr.es/m/5da6f0f0-1364-1876-6978-907678f89a3e@phystech.edu --- src/backend/optimizer/plan/planner.c | 68 +++++++++++++++++--------- src/test/regress/expected/inherit.out | 41 ++++++++++++++++ src/test/regress/expected/triggers.out | 34 +++++++++++++ src/test/regress/sql/inherit.sql | 15 ++++++ src/test/regress/sql/triggers.sql | 27 ++++++++++ 5 files changed, 163 insertions(+), 22 deletions(-) diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 5579dfa65e..bc81535905 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -1583,34 +1583,58 @@ inheritance_planner(PlannerInfo *root) * to get control here. */ - /* - * If we managed to exclude every child rel, return a dummy plan; it - * doesn't even need a ModifyTable node. - */ if (subpaths == NIL) { - set_dummy_rel_pathlist(final_rel); - return; - } + /* + * We managed to exclude every child rel, so generate a dummy path + * representing the empty set. Although it's clear that no data will + * be updated or deleted, we will still need to have a ModifyTable + * node so that any statement triggers are executed. (This could be + * cleaner if we fixed nodeModifyTable.c to support zero child nodes, + * but that probably wouldn't be a net win.) + */ + List *tlist; + Path *dummy_path; - /* - * Put back the final adjusted rtable into the master copy of the Query. - * (We mustn't do this if we found no non-excluded children.) - */ - parse->rtable = final_rtable; - root->simple_rel_array_size = save_rel_array_size; - root->simple_rel_array = save_rel_array; - root->append_rel_array = save_append_rel_array; + /* tlist processing never got done, either */ + tlist = root->processed_tlist = preprocess_targetlist(root); + final_rel->reltarget = create_pathtarget(root, tlist); - /* Must reconstruct master's simple_rte_array, too */ - root->simple_rte_array = (RangeTblEntry **) - palloc0((list_length(final_rtable) + 1) * sizeof(RangeTblEntry *)); - rti = 1; - foreach(lc, final_rtable) + /* Make a dummy path, cf set_dummy_rel_pathlist() */ + dummy_path = (Path *) create_append_path(NULL, final_rel, NIL, NIL, + NULL, 0, false, NIL, -1); + + /* These lists must be nonempty to make a valid ModifyTable node */ + subpaths = list_make1(dummy_path); + subroots = list_make1(root); + resultRelations = list_make1_int(parse->resultRelation); + if (parse->withCheckOptions) + withCheckOptionLists = list_make1(parse->withCheckOptions); + if (parse->returningList) + returningLists = list_make1(parse->returningList); + } + else { - RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc); + /* + * Put back the final adjusted rtable into the master copy of the + * Query. (We mustn't do this if we found no non-excluded children, + * since we never saved an adjusted rtable at all.) + */ + parse->rtable = final_rtable; + root->simple_rel_array_size = save_rel_array_size; + root->simple_rel_array = save_rel_array; + root->append_rel_array = save_append_rel_array; + + /* Must reconstruct master's simple_rte_array, too */ + root->simple_rte_array = (RangeTblEntry **) + palloc0((list_length(final_rtable) + 1) * sizeof(RangeTblEntry *)); + rti = 1; + foreach(lc, final_rtable) + { + RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc); - root->simple_rte_array[rti++] = rte; + root->simple_rte_array[rti++] = rte; + } } /* diff --git a/src/test/regress/expected/inherit.out b/src/test/regress/expected/inherit.out index f259d07535..565d947b6d 100644 --- a/src/test/regress/expected/inherit.out +++ b/src/test/regress/expected/inherit.out @@ -539,6 +539,47 @@ CREATE TEMP TABLE z (b TEXT, PRIMARY KEY(aa, b)) inherits (a); INSERT INTO z VALUES (NULL, 'text'); -- should fail ERROR: null value in column "aa" violates not-null constraint DETAIL: Failing row contains (null, text). +-- Check inherited UPDATE with all children excluded +create table some_tab (a int, b int); +create table some_tab_child () inherits (some_tab); +insert into some_tab_child values(1,2); +explain (verbose, costs off) +update some_tab set a = a + 1 where false; + QUERY PLAN +---------------------------------- + Update on public.some_tab + Update on public.some_tab + -> Result + Output: (a + 1), b, ctid + One-Time Filter: false +(5 rows) + +update some_tab set a = a + 1 where false; +explain (verbose, costs off) +update some_tab set a = a + 1 where false returning b, a; + QUERY PLAN +---------------------------------- + Update on public.some_tab + Output: b, a + Update on public.some_tab + -> Result + Output: (a + 1), b, ctid + One-Time Filter: false +(6 rows) + +update some_tab set a = a + 1 where false returning b, a; + b | a +---+--- +(0 rows) + +table some_tab; + a | b +---+--- + 1 | 2 +(1 row) + +drop table some_tab cascade; +NOTICE: drop cascades to table some_tab_child -- Check UPDATE with inherited target and an inherited source table create temp table foo(f1 int, f2 int); create temp table foo2(f3 int) inherits (foo); diff --git a/src/test/regress/expected/triggers.out b/src/test/regress/expected/triggers.out index 2b908ceec4..d153225b0d 100644 --- a/src/test/regress/expected/triggers.out +++ b/src/test/regress/expected/triggers.out @@ -1716,6 +1716,40 @@ drop table self_ref_trigger; drop function self_ref_trigger_ins_func(); drop function self_ref_trigger_del_func(); -- +-- Check that statement triggers work correctly even with all children excluded +-- +create table stmt_trig_on_empty_upd (a int); +create table stmt_trig_on_empty_upd1 () inherits (stmt_trig_on_empty_upd); +create function update_stmt_notice() returns trigger as $$ +begin + raise notice 'updating %', TG_TABLE_NAME; + return null; +end; +$$ language plpgsql; +create trigger before_stmt_trigger + before update on stmt_trig_on_empty_upd + execute procedure update_stmt_notice(); +create trigger before_stmt_trigger + before update on stmt_trig_on_empty_upd1 + execute procedure update_stmt_notice(); +-- inherited no-op update +update stmt_trig_on_empty_upd set a = a where false returning a+1 as aa; +NOTICE: updating stmt_trig_on_empty_upd + aa +---- +(0 rows) + +-- simple no-op update +update stmt_trig_on_empty_upd1 set a = a where false returning a+1 as aa; +NOTICE: updating stmt_trig_on_empty_upd1 + aa +---- +(0 rows) + +drop table stmt_trig_on_empty_upd cascade; +NOTICE: drop cascades to table stmt_trig_on_empty_upd1 +drop function update_stmt_notice(); +-- -- Check that index creation (or DDL in general) is prohibited in a trigger -- create table trigger_ddl_table ( diff --git a/src/test/regress/sql/inherit.sql b/src/test/regress/sql/inherit.sql index 425052c1f4..5480fe7db4 100644 --- a/src/test/regress/sql/inherit.sql +++ b/src/test/regress/sql/inherit.sql @@ -97,6 +97,21 @@ SELECT relname, d.* FROM ONLY d, pg_class where d.tableoid = pg_class.oid; CREATE TEMP TABLE z (b TEXT, PRIMARY KEY(aa, b)) inherits (a); INSERT INTO z VALUES (NULL, 'text'); -- should fail +-- Check inherited UPDATE with all children excluded +create table some_tab (a int, b int); +create table some_tab_child () inherits (some_tab); +insert into some_tab_child values(1,2); + +explain (verbose, costs off) +update some_tab set a = a + 1 where false; +update some_tab set a = a + 1 where false; +explain (verbose, costs off) +update some_tab set a = a + 1 where false returning b, a; +update some_tab set a = a + 1 where false returning b, a; +table some_tab; + +drop table some_tab cascade; + -- Check UPDATE with inherited target and an inherited source table create temp table foo(f1 int, f2 int); create temp table foo2(f3 int) inherits (foo); diff --git a/src/test/regress/sql/triggers.sql b/src/test/regress/sql/triggers.sql index 60d1dc6f46..8f833b7d10 100644 --- a/src/test/regress/sql/triggers.sql +++ b/src/test/regress/sql/triggers.sql @@ -1177,6 +1177,33 @@ drop table self_ref_trigger; drop function self_ref_trigger_ins_func(); drop function self_ref_trigger_del_func(); +-- +-- Check that statement triggers work correctly even with all children excluded +-- + +create table stmt_trig_on_empty_upd (a int); +create table stmt_trig_on_empty_upd1 () inherits (stmt_trig_on_empty_upd); +create function update_stmt_notice() returns trigger as $$ +begin + raise notice 'updating %', TG_TABLE_NAME; + return null; +end; +$$ language plpgsql; +create trigger before_stmt_trigger + before update on stmt_trig_on_empty_upd + execute procedure update_stmt_notice(); +create trigger before_stmt_trigger + before update on stmt_trig_on_empty_upd1 + execute procedure update_stmt_notice(); + +-- inherited no-op update +update stmt_trig_on_empty_upd set a = a where false returning a+1 as aa; +-- simple no-op update +update stmt_trig_on_empty_upd1 set a = a where false returning a+1 as aa; + +drop table stmt_trig_on_empty_upd cascade; +drop function update_stmt_notice(); + -- -- Check that index creation (or DDL in general) is prohibited in a trigger -- -- 2.40.0