Fix a bug in how we generate partition constraints.

Move the code for doing parent attnos to child attnos mapping for Vars
in partition constraint expressions to a separate function
map_partition_varattnos() and call it from the appropriate places.
Doing it in get_qual_from_partbound(), as is now, would produce wrong
result in certain multi-level partitioning cases, because it only
considers the current pair of parent-child relations.  In certain
multi-level partitioning cases, attnums for the same key attribute(s)
might differ between various levels causing the same attribute to be
numbered differently in different instances of the Var corresponding
to a given attribute.

With this commit, in generate_partition_qual(), we first generate the
the whole partition constraint (considering all levels of partitioning)
and then do the mapping, so that Vars in the final expression are
numbered according the leaf relation (to which it is supposed to apply).

Amit Langote, reviewed by me.

2 files changed, 55 insertions, 0 deletions

diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index d8028c67470..b290bc810eb 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -3339,3 +3339,33 @@ drop cascades to table part_2
 drop cascades to table part_5
 drop cascades to table part_5_a
 drop cascades to table part_1
+-- more tests for certain multi-level partitioning scenarios
+create table p (a int, b int) partition by range (a, b);
+create table p1 (b int, a int not null) partition by range (b);
+create table p11 (like p1);
+alter table p11 drop a;
+alter table p11 add a int;
+alter table p11 drop a;
+alter table p11 add a int not null;
+-- attnum for key attribute 'a' is different in p, p1, and p11
+select attrelid::regclass, attname, attnum
+from pg_attribute
+where attname = 'a'
+ and (attrelid = 'p'::regclass
+   or attrelid = 'p1'::regclass
+   or attrelid = 'p11'::regclass);
+ attrelid | attname | attnum 
+----------+---------+--------
+ p        | a       |      1
+ p1       | a       |      2
+ p11      | a       |      4
+(3 rows)
+
+alter table p1 attach partition p11 for values from (2) to (5);
+insert into p1 (a, b) values (2, 3);
+-- check that partition validation scan correctly detects violating rows
+alter table p attach partition p1 for values from (1, 2) to (1, 10);
+ERROR:  partition constraint is violated by some row
+-- cleanup
+drop table p, p1 cascade;
+NOTICE:  drop cascades to table p11
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 22652665172..5d07e2ede44 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -2191,3 +2191,28 @@ ALTER TABLE list_parted2 ALTER COLUMN b TYPE text;
 
 -- cleanup
 DROP TABLE list_parted, list_parted2, range_parted CASCADE;
+
+-- more tests for certain multi-level partitioning scenarios
+create table p (a int, b int) partition by range (a, b);
+create table p1 (b int, a int not null) partition by range (b);
+create table p11 (like p1);
+alter table p11 drop a;
+alter table p11 add a int;
+alter table p11 drop a;
+alter table p11 add a int not null;
+-- attnum for key attribute 'a' is different in p, p1, and p11
+select attrelid::regclass, attname, attnum
+from pg_attribute
+where attname = 'a'
+ and (attrelid = 'p'::regclass
+   or attrelid = 'p1'::regclass
+   or attrelid = 'p11'::regclass);
+
+alter table p1 attach partition p11 for values from (2) to (5);
+
+insert into p1 (a, b) values (2, 3);
+-- check that partition validation scan correctly detects violating rows
+alter table p attach partition p1 for values from (1, 2) to (1, 10);
+
+-- cleanup
+drop table p, p1 cascade;