-- We create two sets of source and target tables, one set in Postgres and
-- the other in Citus distributed. We run the _exact_ MERGE SQL on both sets
-- and compare the final results of the target tables in Postgres and Citus.
-- The results should match. This process is repeated for various combinations
-- of MERGE SQL.
DROP SCHEMA IF EXISTS merge_repartition2_schema CASCADE;
NOTICE:  schema "merge_repartition2_schema" does not exist, skipping
CREATE SCHEMA merge_repartition2_schema;
SET search_path TO merge_repartition2_schema;
SET citus.shard_count TO 4;
SET citus.next_shard_id TO 6000000;
SET citus.explain_all_tasks TO true;
SET citus.shard_replication_factor TO 1;
SET citus.max_adaptive_executor_pool_size TO 1;
SET client_min_messages = warning;
SELECT 1 FROM master_add_node('localhost', :master_port, groupid => 0);
 ?column?
---------------------------------------------------------------------
        1
(1 row)

RESET client_min_messages;
CREATE TABLE pg_target(id int, val int);
CREATE TABLE pg_source(id int, val int, const int);
CREATE TABLE citus_target(id int, val int);
CREATE TABLE citus_source(id int, val int, const int);
SELECT citus_add_local_table_to_metadata('citus_target');
 citus_add_local_table_to_metadata
---------------------------------------------------------------------

(1 row)

SELECT citus_add_local_table_to_metadata('citus_source');
 citus_add_local_table_to_metadata
---------------------------------------------------------------------

(1 row)

CREATE OR REPLACE FUNCTION cleanup_data() RETURNS VOID SET search_path TO merge_repartition2_schema AS $$
    TRUNCATE pg_target;
    TRUNCATE pg_source;
    TRUNCATE citus_target;
    TRUNCATE citus_source;
    SELECT undistribute_table('citus_target');
    SELECT undistribute_table('citus_source');
$$
LANGUAGE SQL;
--
-- Load same set of data to both Postgres and Citus tables
--
CREATE OR REPLACE FUNCTION setup_data() RETURNS VOID SET search_path TO merge_repartition2_schema AS $$
    INSERT INTO pg_source SELECT i, i+1, 1 FROM generate_series(1, 100000) i;
    INSERT INTO pg_target SELECT i, 1 FROM generate_series(50001, 100000) i;
    INSERT INTO citus_source SELECT i, i+1, 1 FROM generate_series(1, 100000) i;
    INSERT INTO citus_target SELECT i, 1 FROM generate_series(50001, 100000) i;
$$
LANGUAGE SQL;
--
-- Compares the final target tables, merge-modified data, of both Postgres and Citus tables
--
CREATE OR REPLACE FUNCTION check_data(table1_name text, column1_name text, table2_name text, column2_name text)
RETURNS VOID SET search_path TO merge_repartition2_schema AS $$
DECLARE
    table1_avg numeric;
    table2_avg numeric;
BEGIN
    EXECUTE format('SELECT COALESCE(AVG(%I), 0) FROM %I', column1_name, table1_name) INTO table1_avg;
    EXECUTE format('SELECT COALESCE(AVG(%I), 0) FROM %I', column2_name, table2_name) INTO table2_avg;

    IF table1_avg > table2_avg THEN
        RAISE EXCEPTION 'The average of %.% is greater than %.%', table1_name, column1_name, table2_name, column2_name;
    ELSIF table1_avg < table2_avg THEN
        RAISE EXCEPTION 'The average of %.% is less than %.%', table1_name, column1_name, table2_name, column2_name;
    ELSE
        RAISE NOTICE 'The average of %.% is equal to %.%', table1_name, column1_name, table2_name, column2_name;
    END IF;
END;
$$ LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION compare_data() RETURNS VOID SET search_path TO merge_repartition2_schema AS $$
    SELECT check_data('pg_target', 'id', 'citus_target', 'id');
    SELECT check_data('pg_target', 'val', 'citus_target', 'val');
$$
LANGUAGE SQL;
-- Test nested cte
SELECT cleanup_data();
NOTICE:  creating a new table for merge_repartition2_schema.citus_target
CONTEXT:  SQL function "cleanup_data" statement 5
NOTICE:  moving the data of merge_repartition2_schema.citus_target
CONTEXT:  SQL function "cleanup_data" statement 5
NOTICE:  dropping the old merge_repartition2_schema.citus_target
CONTEXT:  SQL function "cleanup_data" statement 5
NOTICE:  renaming the new table to merge_repartition2_schema.citus_target
CONTEXT:  SQL function "cleanup_data" statement 5
NOTICE:  creating a new table for merge_repartition2_schema.citus_source
CONTEXT:  SQL function "cleanup_data" statement 6
NOTICE:  moving the data of merge_repartition2_schema.citus_source
CONTEXT:  SQL function "cleanup_data" statement 6
NOTICE:  dropping the old merge_repartition2_schema.citus_source
CONTEXT:  SQL function "cleanup_data" statement 6
NOTICE:  renaming the new table to merge_repartition2_schema.citus_source
CONTEXT:  SQL function "cleanup_data" statement 6
 cleanup_data
---------------------------------------------------------------------

(1 row)

SELECT setup_data();
 setup_data
---------------------------------------------------------------------

(1 row)

SELECT create_distributed_table('citus_target', 'id');
NOTICE:  Copying data from local table...
NOTICE:  copying the data has completed
DETAIL:  The local data in the table is no longer visible, but is still on disk.
HINT:  To remove the local data, run: SELECT truncate_local_data_after_distributing_table($$merge_repartition2_schema.citus_target$$)
 create_distributed_table
---------------------------------------------------------------------

(1 row)

SELECT create_distributed_table('citus_source', 'id', colocate_with=>'none');
NOTICE:  Copying data from local table...
NOTICE:  copying the data has completed
DETAIL:  The local data in the table is no longer visible, but is still on disk.
HINT:  To remove the local data, run: SELECT truncate_local_data_after_distributing_table($$merge_repartition2_schema.citus_source$$)
 create_distributed_table
---------------------------------------------------------------------

(1 row)

WITH cte_top AS(WITH cte_1 AS (WITH cte_2 AS (SELECT id, val FROM pg_source) SELECT * FROM cte_2) SELECT * FROM cte_1)
MERGE INTO pg_target t
USING (SELECT const, val, id FROM pg_source WHERE id IN (SELECT id FROM cte_top)) as s
ON (s.id = t.id)
WHEN MATCHED AND t.id <= 75000 THEN
	UPDATE SET val = (s.val::int8+1)
WHEN MATCHED THEN
	DELETE
WHEN NOT MATCHED THEN
	INSERT VALUES (s.id, s.val);
WITH cte_top AS(WITH cte_1 AS (WITH cte_2 AS (SELECT id, val FROM citus_source) SELECT * FROM cte_2) SELECT * FROM cte_1)
MERGE INTO citus_target t
USING (SELECT const, val, id FROM citus_source WHERE id IN (SELECT id FROM cte_top)) as s
ON (s.id = t.id)
WHEN MATCHED AND t.id <= 75000 THEN
	UPDATE SET val = (s.val::int8+1)
WHEN MATCHED THEN
	DELETE
WHEN NOT MATCHED THEN
	INSERT VALUES (s.id, s.val);
SELECT compare_data();
NOTICE:  The average of pg_target.id is equal to citus_target.id
CONTEXT:  PL/pgSQL function check_data(text,text,text,text) line XX at RAISE
SQL function "compare_data" statement 1
NOTICE:  The average of pg_target.val is equal to citus_target.val
CONTEXT:  PL/pgSQL function check_data(text,text,text,text) line XX at RAISE
SQL function "compare_data" statement 2
 compare_data
---------------------------------------------------------------------

(1 row)

-- Test aggregate function in source query
MERGE INTO pg_target t
USING (SELECT count(id+1)::text as value, val as key FROM pg_source group by key) s
ON t.id = s.key
WHEN MATCHED AND t.id <= 75000 THEN
        UPDATE SET val = (s.value::int8+1)
WHEN MATCHED THEN
        DELETE
WHEN NOT MATCHED THEN
        INSERT VALUES(s.key, value::int4+10);
MERGE INTO citus_target t
USING (SELECT count(id+1)::text as value, val as key FROM citus_source group by key) s
ON t.id = s.key
WHEN MATCHED AND t.id <= 75000 THEN
        UPDATE SET val = (s.value::int8+1)
WHEN MATCHED THEN
        DELETE
WHEN NOT MATCHED THEN
        INSERT VALUES(s.key, value::int4+10);
SELECT compare_data();
NOTICE:  The average of pg_target.id is equal to citus_target.id
CONTEXT:  PL/pgSQL function check_data(text,text,text,text) line XX at RAISE
SQL function "compare_data" statement 1
NOTICE:  The average of pg_target.val is equal to citus_target.val
CONTEXT:  PL/pgSQL function check_data(text,text,text,text) line XX at RAISE
SQL function "compare_data" statement 2
 compare_data
---------------------------------------------------------------------

(1 row)

---- https://github.com/citusdata/citus/issues/8180 ----
CREATE TABLE dist_1 (a int, b int, c int);
CREATE TABLE dist_2 (a int, b int, c int);
CREATE TABLE dist_different_order_1 (b int, a int, c int);
SELECT create_distributed_table('dist_1', 'a');
 create_distributed_table
---------------------------------------------------------------------

(1 row)

SELECT create_distributed_table('dist_2', 'a');
 create_distributed_table
---------------------------------------------------------------------

(1 row)

SELECT create_distributed_table('dist_different_order_1', 'a');
 create_distributed_table
---------------------------------------------------------------------

(1 row)

MERGE INTO dist_1
USING dist_2
ON (dist_1.a = dist_2.b)
WHEN MATCHED THEN UPDATE SET b = dist_2.b;
MERGE INTO dist_1
USING dist_1 src
ON (dist_1.a = src.b)
WHEN MATCHED THEN UPDATE SET b = src.b;
MERGE INTO dist_different_order_1
USING dist_1
ON (dist_different_order_1.a = dist_1.b)
WHEN MATCHED THEN UPDATE SET b = dist_1.b;
CREATE TABLE dist_1_cast (a int, b int);
CREATE TABLE dist_2_cast (a int, b numeric);
SELECT create_distributed_table('dist_1_cast', 'a');
 create_distributed_table
---------------------------------------------------------------------

(1 row)

SELECT create_distributed_table('dist_2_cast', 'a');
 create_distributed_table
---------------------------------------------------------------------

(1 row)

MERGE INTO dist_1_cast
USING dist_2_cast
ON (dist_1_cast.a = dist_2_cast.b)
WHEN MATCHED THEN UPDATE SET b = dist_2_cast.b;
ERROR:  In the MERGE ON clause, there is a datatype mismatch between target's distribution column and the expression originating from the source.
DETAIL:  If the types are different, Citus uses different hash functions for the two column types, which might lead to incorrect repartitioning of the result data
MERGE INTO dist_1_cast
USING (SELECT a, b::int as b FROM dist_2_cast) dist_2_cast
ON (dist_1_cast.a = dist_2_cast.b)
WHEN MATCHED THEN UPDATE SET b = dist_2_cast.b;
-- a more sophisticated example
CREATE TABLE dist_source (tstamp_col timestamp, int_col int, text_arr_col text[], text_col text, json_col jsonb);
CREATE TABLE dist_target (text_col text, tstamp_col timestamp, json_col jsonb, text_arr_col text[], int_col int);
CREATE TABLE local_source (tstamp_col timestamp, int_col int, text_arr_col text[], text_col text, json_col jsonb);
CREATE TABLE local_target (text_col text, tstamp_col timestamp, json_col jsonb, text_arr_col text[], int_col int);
SELECT create_distributed_table('dist_source', 'tstamp_col');
 create_distributed_table
---------------------------------------------------------------------

(1 row)

SELECT create_distributed_table('dist_target', 'int_col');
 create_distributed_table
---------------------------------------------------------------------

(1 row)

INSERT INTO dist_source (tstamp_col, int_col, text_arr_col, text_col, json_col)
SELECT TIMESTAMP '2025-01-01 00:00:00' + (i || ' days')::interval,
       i,
       ARRAY[i::text, (i+1)::text, (i+2)::text],
       'source_' || i,
       ('{"a": ' || i || ', "b": ' || i+1 || '}')::jsonb
FROM generate_series(1001, 2000) i;
INSERT INTO dist_source (tstamp_col, int_col, text_arr_col, text_col, json_col)
SELECT TIMESTAMP '2025-01-01 00:00:00' + (i || ' days')::interval,
       i,
       ARRAY[i::text, (i+1)::text, (i+2)::text],
       'source_' || i,
       ('{"a": ' || i || ', "b": ' || i+1 || '}')::jsonb
FROM generate_series(901, 1000) i;
INSERT INTO dist_target (tstamp_col, int_col, text_arr_col, text_col, json_col)
SELECT TIMESTAMP '2025-01-01 00:00:00' + (i || ' days')::interval,
       i,
       ARRAY[(i-1)::text, (i)::text, (i+1)::text],
       'source_' || i,
       ('{"a": ' || i*5 || ', "b": ' || i+20 || '}')::jsonb
FROM generate_series(1501, 2000) i;
INSERT INTO dist_target (tstamp_col, int_col, text_arr_col, text_col, json_col)
SELECT TIMESTAMP '2025-01-01 00:00:00' + (i || ' days')::interval,
       i,
       ARRAY[(i-1)::text, (i)::text, (i+1)::text],
       'source_' || i-1,
       ('{"a": ' || i*5 || ', "b": ' || i+20 || '}')::jsonb
FROM generate_series(1401, 1500) i;
INSERT INTO local_source SELECT * FROM dist_source;
INSERT INTO local_target SELECT * FROM dist_target;
-- execute the query on distributed tables
MERGE INTO dist_target target_alias
USING dist_source source_alias
ON (target_alias.text_col = source_alias.text_col AND target_alias.int_col = source_alias.int_col)
WHEN MATCHED THEN UPDATE SET
    tstamp_col = source_alias.tstamp_col + interval '3 day',
    text_arr_col = array_append(source_alias.text_arr_col, 'updated_' || source_alias.text_col),
    json_col = ('{"a": "' || replace(source_alias.text_col, '"', '\"') || '"}')::jsonb,
    text_col = source_alias.json_col->>'a'
WHEN NOT MATCHED THEN
  INSERT VALUES (source_alias.text_col, source_alias.tstamp_col, source_alias.json_col, source_alias.text_arr_col, source_alias.int_col );
-- execute the same query on local tables, everything is the same except table names behind the aliases
MERGE INTO local_target target_alias
USING local_source source_alias
ON (target_alias.text_col = source_alias.text_col AND target_alias.int_col = source_alias.int_col)
WHEN MATCHED THEN UPDATE SET
    tstamp_col = source_alias.tstamp_col + interval '3 day',
    text_arr_col = array_append(source_alias.text_arr_col, 'updated_' || source_alias.text_col),
    json_col = ('{"a": "' || replace(source_alias.text_col, '"', '\"') || '"}')::jsonb,
    text_col = source_alias.json_col->>'a'
WHEN NOT MATCHED THEN
  INSERT VALUES (source_alias.text_col, source_alias.tstamp_col, source_alias.json_col, source_alias.text_arr_col, source_alias.int_col );
-- compare both targets
SELECT COUNT(*) = 0 AS targets_match
FROM (
    SELECT * FROM dist_target
    EXCEPT
    SELECT * FROM local_target
    UNION ALL
    SELECT * FROM local_target
    EXCEPT
    SELECT * FROM dist_target
) q;
 targets_match
---------------------------------------------------------------------
 t
(1 row)

SET client_min_messages TO WARNING;
DROP SCHEMA merge_repartition2_schema CASCADE;