-- Logical checksums must depend on the data only: not on dropped columns, not
-- on the search_path, and physical tuple checksums with the header must not
-- depend on hint bits that readers set lazily.
-- Dropped columns do not matter (table, tuple and cell level).
CREATE TABLE port_plain (x int, y text, z int);
INSERT INTO port_plain VALUES (1, 'p', 2), (3, 'q', 4);
CREATE TABLE port_dropped (junk int, x int, y text, z int);
INSERT INTO port_dropped VALUES (0, 1, 'p', 2), (0, 3, 'q', 4);
ALTER TABLE port_dropped DROP COLUMN junk;
SELECT pg_table_logical_checksum('port_plain') =
       pg_table_logical_checksum('port_dropped') AS table_same,
       pg_tuple_logical_checksum('port_plain', '(0,1)') =
       pg_tuple_logical_checksum('port_dropped', '(0,1)') AS tuple_same,
       pg_cell_checksum('port_plain', '(0,1)', 3) =
       pg_cell_checksum('port_dropped', '(0,1)', 4) AS cell_same,
       pg_cell_checksum('port_dropped', '(0,1)', 1) IS NULL AS dropped_is_null;
 table_same | tuple_same | cell_same | dropped_is_null 
------------+------------+-----------+-----------------
 t          | t          | t         | t
(1 row)

-- The search_path does not matter for user-defined types.  The same type name
-- in two schemas gives the same checksum, whichever schema is visible.
CREATE SCHEMA port_s1;
-- Dropped composite attributes do not matter either.
CREATE TYPE public.port_pair AS (a int, junk int, b int);
ALTER TYPE public.port_pair DROP ATTRIBUTE junk;
CREATE TYPE port_s1.port_pair AS (a int, b int);
CREATE TABLE port_comp1 (v public.port_pair);
CREATE TABLE port_comp2 (v port_s1.port_pair);
INSERT INTO port_comp1 VALUES (ROW(1, 2));
INSERT INTO port_comp2 VALUES (ROW(1, 2));
SELECT pg_table_logical_checksum('port_comp1') =
       pg_table_logical_checksum('port_comp2') AS composite_same;
 composite_same 
----------------
 t
(1 row)

CREATE TYPE public.port_mood AS ENUM ('sad', 'ok');
CREATE TYPE port_s1.port_mood AS ENUM ('sad', 'ok');
CREATE TABLE port_m_public (v public.port_mood, w public.port_mood[]);
CREATE TABLE port_m_s1 (v port_s1.port_mood, w port_s1.port_mood[]);
INSERT INTO port_m_public VALUES ('ok', '{ok,sad}');
INSERT INTO port_m_s1 VALUES ('ok', '{ok,sad}');
SET search_path = public, pg_catalog;
SELECT pg_table_logical_checksum('port_m_public') =
       pg_table_logical_checksum('port_m_s1') AS same_default_path;
 same_default_path 
-------------------
 t
(1 row)

SET search_path = port_s1, public, pg_catalog;
SELECT pg_table_logical_checksum('port_m_public') =
       pg_table_logical_checksum('port_m_s1') AS same_s1_path;
 same_s1_path 
--------------
 t
(1 row)

RESET search_path;
-- Physical tuple checksums that include the header must not change when a
-- reader sets hint bits.
CREATE TABLE port_hint (x int);
INSERT INTO port_hint VALUES (1);
CREATE TEMP TABLE port_hint_sums (label text, sum int);
INSERT INTO port_hint_sums
    SELECT 'before', pg_tuple_physical_checksum('port_hint', '(0,1)', true);
SELECT count(*) FROM port_hint;   -- sets the xmin-committed hint bit
 count 
-------
     1
(1 row)

INSERT INTO port_hint_sums
    SELECT 'after', pg_tuple_physical_checksum('port_hint', '(0,1)', true);
SELECT (SELECT sum FROM port_hint_sums WHERE label = 'before') =
       (SELECT sum FROM port_hint_sums WHERE label = 'after')
       AS header_checksum_ignores_hints;
 header_checksum_ignores_hints 
-------------------------------
 t
(1 row)

DROP TABLE port_plain, port_dropped, port_comp1, port_comp2, port_m_public,
           port_m_s1, port_hint;
DROP TYPE public.port_pair;
DROP TYPE public.port_mood;
DROP SCHEMA port_s1 CASCADE;
NOTICE:  drop cascades to 2 other objects
DETAIL:  drop cascades to type port_s1.port_pair
drop cascades to type port_s1.port_mood