05b5220248
CopyToJsonOneRow() stamped the row datum with the query's descriptor
only when the slot's descriptor was of type RECORD. A scan that does
not project returns the table's row type, so the keys came from the
table, not the query, losing column aliases and mislabelling rows
from UNION ALL branches with different column orders.
Fix by always using the query's descriptor. For non-virtual slots,
heap_copy_tuple_as_datum() can just be passed that descriptor, so
there is no extra cost. This is safe because a scan skips projection
only when tlist_matches_tupdesc() holds, so the layouts match.
Bug introduced in 7dadd38cda.
Reported-by: Shihao Zhong <zhong950419@gmail.com>
Reviewed-by: Shihao Zhong <zhong950419@gmail.com>
Reviewed-by: João Marcelo Detomini <joao.detomini@enterprisedb.com>
Discussion: https://postgr.es/m/CAGRkXqQHjxgufHPz86+dxGaQZt37hikduUArYtfbn2_3mryZAw@mail.gmail.com
Backpatch-through: 19
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/19/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/19/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.