Fix attribute mapping for COPY TO on partitioned tables.

Commit 4bea91f21f61 enabled COPY TO on a partitioned table to read
tuples from its partitions and mapped them to the root table's tuple
descriptor before output. However, it incorrectly built the attribute
map from the root table to the partition.

This commit fixes by building the attribute map from the partition to
the root table, ensuring that partition attributes are correctly
mapped to their corresponding root attributes.

Author: Chao Li <lic@highgo.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/85EA70F3-C3DB-477B-B856-EA569FDAAE7C@gmail.com

diff --git a/src/backend/commands/copyto.c b/src/backend/commands/copyto.c
index 1085d0d5b8d28d2d501ff339ced51c68fc6e3c73..ffed63a2986bb814fe26709de7ca21065400d412 100644 (file)
--- a/src/backend/commands/copyto.c
+++ b/src/backend/commands/copyto.c
@@ -1348,8 +1348,8 @@ CopyRelationTo(CopyToState cstate, Relation rel, Relation root_rel, uint64 *proc
        if (root_rel != NULL)
        {
                root_slot = table_slot_create(root_rel, NULL);
-               map = build_attrmap_by_name_if_req(RelationGetDescr(root_rel),
-                                                                                  RelationGetDescr(rel),
+               map = build_attrmap_by_name_if_req(RelationGetDescr(rel),
+                                                                                  RelationGetDescr(root_rel),
                                                                                   false);
        }
 

diff --git a/src/test/regress/expected/copy.out b/src/test/regress/expected/copy.out
index 1714faab39c2fd6a94a0d1e7c4af8247de2ff078..37498cdd6e7aaea7829b09c6e76bec875738a6da 100644 (file)
--- a/src/test/regress/expected/copy.out
+++ b/src/test/regress/expected/copy.out
@@ -594,3 +594,14 @@ id val
 5      15
 6      16
 DROP TABLE PP;
+-- Check if COPY TO handles dropped columns in partitions.
+CREATE TABLE pp_dropcol (id int, val int) PARTITION BY RANGE (id);
+CREATE TABLE pp_dropcol_1 (dropme int, id int, val int);
+ALTER TABLE pp_dropcol_1 DROP COLUMN dropme;
+ALTER TABLE pp_dropcol ATTACH PARTITION pp_dropcol_1 FOR VALUES FROM (1) TO (10);
+INSERT INTO pp_dropcol VALUES (1, 11), (2, 12);
+COPY pp_dropcol TO stdout(header);
+id     val
+1      11
+2      12
+DROP TABLE pp_dropcol;

diff --git a/src/test/regress/sql/copy.sql b/src/test/regress/sql/copy.sql
index eaad290b257bc9a06e202926632e69ac4bdb7030..094fd76c12bfbc61fe0f7a83db91cbed1d32acaf 100644 (file)
--- a/src/test/regress/sql/copy.sql
+++ b/src/test/regress/sql/copy.sql
@@ -535,3 +535,12 @@ CREATE TABLE pp_510 PARTITION OF pp_2 FOR VALUES FROM (5) TO (10);
 INSERT INTO pp SELECT g, 10 + g FROM generate_series(1,6) g;
 COPY pp TO stdout(header);
 DROP TABLE PP;
+
+-- Check if COPY TO handles dropped columns in partitions.
+CREATE TABLE pp_dropcol (id int, val int) PARTITION BY RANGE (id);
+CREATE TABLE pp_dropcol_1 (dropme int, id int, val int);
+ALTER TABLE pp_dropcol_1 DROP COLUMN dropme;
+ALTER TABLE pp_dropcol ATTACH PARTITION pp_dropcol_1 FOR VALUES FROM (1) TO (10);
+INSERT INTO pp_dropcol VALUES (1, 11), (2, 12);
+COPY pp_dropcol TO stdout(header);
+DROP TABLE pp_dropcol;