
CREATE SCHEMA fast_path_router_select;
SET search_path TO fast_path_router_select;

SET citus.next_shard_id TO 1840000;

-- all the tests in this file is intended for testing fast-path
-- router planner, so we're explicitly enabling itin this file.
-- We've bunch of other tests that triggers non-fast-path-router
-- planner (note this is already true by default)
SET citus.enable_fast_path_router_planner TO true;


-- ===================================================================
-- test router planner functionality for via fast path on
-- single shard select queries
-- ===================================================================

CREATE TABLE articles_hash (
	id bigint NOT NULL,
	author_id bigint NOT NULL,
	title varchar(20) NOT NULL,
	word_count integer
);

CREATE TABLE articles_range (
	id bigint NOT NULL,
	author_id bigint NOT NULL,
	title varchar(20) NOT NULL,
	word_count integer
);

CREATE TABLE articles_append (
	id bigint NOT NULL,
	author_id bigint NOT NULL,
	title varchar(20) NOT NULL,
	word_count integer
);

-- Check for the existence of line 'DEBUG:  Creating router plan'
-- to determine if router planner is used.

-- this table is used in a CTE test
CREATE TABLE authors_hash ( name varchar(20), id bigint );
CREATE TABLE authors_range ( name varchar(20), id bigint );

SET citus.shard_replication_factor TO 1;

SET citus.shard_count TO 2;
SELECT create_distributed_table('articles_hash', 'author_id');

CREATE TABLE authors_reference ( name varchar(20), id bigint );
SELECT create_reference_table('authors_reference');

-- create a bunch of test data
INSERT INTO articles_hash VALUES (1,  1, 'arsenous', 9572), (2,  2, 'abducing', 13642),( 3,  3, 'asternal', 10480),( 4,  4, 'altdorfer', 14551),( 5,  5, 'aruru', 11389),
								 (6,  6, 'atlases', 15459),(7,  7, 'aseptic', 12298),( 8,  8, 'agatized', 16368),(9,  9, 'alligate', 438),
								 (10, 10, 'aggrandize', 17277),(11,  1, 'alamo', 1347),(12,  2, 'archiblast', 18185),
								 (13,  3, 'aseyev', 2255),(14,  4, 'andesite', 19094),(15,  5, 'adversa', 3164),
								 (16,  6, 'allonym', 2),(17,  7, 'auriga', 4073),(18,  8, 'assembly', 911),(19,  9, 'aubergiste', 4981),
								 (20, 10, 'absentness', 1820),(21,  1, 'arcading', 5890),(22,  2, 'antipope', 2728),(23,  3, 'abhorring', 6799),
								 (24,  4, 'audacious', 3637),(25,  5, 'antehall', 7707),(26,  6, 'abington', 4545),(27,  7, 'arsenous', 8616),
								 (28,  8, 'aerophyte', 5454),(29,  9, 'amateur', 9524),(30, 10, 'andelee', 6363),(31,  1, 'athwartships', 7271),
								 (32,  2, 'amazon', 11342),(33,  3, 'autochrome', 8180),(34,  4, 'amnestied', 12250),(35,  5, 'aminate', 9089),
								 (36,  6, 'ablation', 13159),(37,  7, 'archduchies', 9997),(38,  8, 'anatine', 14067),(39,  9, 'anchises', 10906),
								 (40, 10, 'attemper', 14976),(41,  1, 'aznavour', 11814),(42,  2, 'ausable', 15885),(43,  3, 'affixal', 12723),
								 (44,  4, 'anteport', 16793),(45,  5, 'afrasia', 864),(46,  6, 'atlanta', 17702),(47,  7, 'abeyance', 1772),
								 (48,  8, 'alkylic', 18610),(49,  9, 'anyone', 2681),(50, 10, 'anjanette', 19519);

SET client_min_messages TO 'DEBUG2';

-- test simple select for a single row
SELECT * FROM articles_hash WHERE author_id = 10 AND id = 50;

-- get all titles by a single author
SELECT title FROM articles_hash WHERE author_id = 10;

-- try ordering them by word count
SELECT title, word_count FROM articles_hash
	WHERE author_id = 10
	ORDER BY word_count DESC NULLS LAST;

-- look at last two articles by an author
SELECT title, id FROM articles_hash
	WHERE author_id = 5
	ORDER BY id
	LIMIT 2;

-- find all articles by two authors in same shard
-- but plan is not fast path router plannable due to
-- two distribution columns in the query
SELECT title, author_id FROM articles_hash
	WHERE author_id = 7 OR author_id = 8
	ORDER BY author_id ASC, id;

-- having clause is supported if it goes to a single shard
-- and single dist. key on the query
SELECT author_id, sum(word_count) AS corpus_size FROM articles_hash
	WHERE author_id = 1
	GROUP BY author_id
	HAVING sum(word_count) > 1000
	ORDER BY sum(word_count) DESC;

-- fast path planner only support = operator
SELECT * FROM articles_hash WHERE author_id <= 1;
SELECT * FROM articles_hash WHERE author_id IN (1, 3);

-- queries with CTEs cannot go through fast-path planning
WITH first_author AS ( SELECT id FROM articles_hash WHERE author_id = 1)
SELECT * FROM first_author;

-- two CTE joins also cannot go through fast-path planning
WITH id_author AS ( SELECT id, author_id FROM articles_hash WHERE author_id = 1),
id_title AS (SELECT id, title from articles_hash WHERE author_id = 1)
SELECT * FROM id_author, id_title WHERE id_author.id = id_title.id;

-- this is a different case where each CTE is recursively planned and those goes
-- through the fast-path router planner, but the top level join is not
WITH id_author AS ( SELECT id, author_id FROM articles_hash WHERE author_id = 1),
id_title AS (SELECT id, title from articles_hash WHERE author_id = 2)
SELECT * FROM id_author, id_title WHERE id_author.id = id_title.id;

CREATE TABLE company_employees (company_id int, employee_id int, manager_id int);
SELECT master_create_distributed_table('company_employees', 'company_id', 'hash');

-- do not print notices from workers since the order is not deterministic
SET client_min_messages TO DEFAULT;
SELECT master_create_worker_shards('company_employees', 4, 1);
SET client_min_messages TO 'DEBUG2';

INSERT INTO company_employees values(1, 1, 0);
INSERT INTO company_employees values(1, 2, 1);
INSERT INTO company_employees values(1, 3, 1);
INSERT INTO company_employees values(1, 4, 2);
INSERT INTO company_employees values(1, 5, 4);

INSERT INTO company_employees values(3, 1, 0);
INSERT INTO company_employees values(3, 15, 1);
INSERT INTO company_employees values(3, 3, 1);

-- recursive CTEs are also cannot go through fast
-- path planning
WITH RECURSIVE hierarchy as (
	SELECT *, 1 AS level
		FROM company_employees
		WHERE company_id = 1 and manager_id = 0
	UNION
	SELECT ce.*, (h.level+1)
		FROM hierarchy h JOIN company_employees ce
			ON (h.employee_id = ce.manager_id AND
				h.company_id = ce.company_id AND
				ce.company_id = 1))
SELECT * FROM hierarchy WHERE LEVEL <= 2;

WITH update_article AS (
    UPDATE articles_hash SET word_count = 10 WHERE id = 1 AND word_count = 9 RETURNING *
)
SELECT * FROM update_article;

WITH delete_article AS (
    DELETE FROM articles_hash WHERE id = 1 AND word_count = 10 RETURNING *
)
SELECT * FROM delete_article;

-- grouping sets are supported via fast-path
SELECT
	id, substring(title, 2, 1) AS subtitle, count(*)
	FROM articles_hash
	WHERE author_id = 1
	GROUP BY GROUPING SETS ((id),(subtitle))
	ORDER BY id, subtitle;

-- grouping sets are not supported with multiple quals
SELECT
	id, substring(title, 2, 1) AS subtitle, count(*)
	FROM articles_hash
	WHERE author_id = 1 or author_id = 2
	GROUP BY GROUPING SETS ((id),(subtitle))
	ORDER BY id, subtitle;

-- queries which involve functions in FROM clause are not supported via fast path planning
SELECT * FROM articles_hash, position('om' in 'Thomas') WHERE author_id = 1;

-- sublinks are not supported via fast path planning
SELECT * FROM articles_hash
WHERE author_id IN (SELECT author_id FROM articles_hash WHERE author_id = 2)
ORDER BY articles_hash.id;

-- subqueries are not supported via fast path planning
SELECT articles_hash.id,test.word_count
FROM articles_hash, (SELECT id, word_count FROM articles_hash) AS test WHERE test.id = articles_hash.id
ORDER BY test.word_count DESC, articles_hash.id LIMIT 5;

SELECT articles_hash.id,test.word_count
FROM articles_hash, (SELECT id, word_count FROM articles_hash) AS test
WHERE test.id = articles_hash.id and articles_hash.author_id = 1
ORDER BY articles_hash.id;

-- subqueries are not supported in SELECT clause
SELECT a.title AS name, (SELECT a2.id FROM articles_hash a2 WHERE a.id = a2.id  LIMIT 1)
						 AS special_price FROM articles_hash a;

-- simple lookup query just works
SELECT *
	FROM articles_hash
	WHERE author_id = 1;

-- below query hits a single shard but with multiple filters
-- so cannot go via fast-path
SELECT *
	FROM articles_hash
	WHERE author_id = 1 OR author_id = 17;

-- rename the output columns
SELECT id as article_id, word_count * id as random_value
	FROM articles_hash
	WHERE author_id = 1;

-- joins do not go through fast-path planning
SELECT a.author_id as first_author, b.word_count as second_word_count
	FROM articles_hash a, articles_hash b
	WHERE a.author_id = 10 and a.author_id = b.author_id
	LIMIT 3;

-- single shard select with limit goes through fast-path planning
SELECT *
	FROM articles_hash
	WHERE author_id = 1
	LIMIT 3;

-- single shard select with limit + offset goes through fast-path planning
SELECT *
	FROM articles_hash
	WHERE author_id = 1
	LIMIT 2
	OFFSET 1;

-- single shard select with limit + offset + order by goes through fast-path planning
SELECT *
	FROM articles_hash
	WHERE author_id = 1
	ORDER BY id desc
	LIMIT 2
	OFFSET 1;

-- single shard select with group by on non-partition column goes through fast-path planning
SELECT id
	FROM articles_hash
	WHERE author_id = 1
	GROUP BY id
	ORDER BY id;

-- single shard select with distinct goes through fast-path planning
SELECT DISTINCT id
	FROM articles_hash
	WHERE author_id = 1
	ORDER BY id;

-- single shard aggregate goes through fast-path planning
SELECT avg(word_count)
	FROM articles_hash
	WHERE author_id = 2;

-- max, min, sum, count goes through fast-path planning
SELECT max(word_count) as max, min(word_count) as min,
	   sum(word_count) as sum, count(word_count) as cnt
	FROM articles_hash
	WHERE author_id = 2;


-- queries with aggregates and group by goes through fast-path planning
SELECT max(word_count)
	FROM articles_hash
	WHERE author_id = 1
	GROUP BY author_id;


-- set operations are not supported via fast-path planning
SELECT * FROM (
	SELECT * FROM articles_hash WHERE author_id = 1
	UNION
	SELECT * FROM articles_hash WHERE author_id = 3
) AS combination
ORDER BY id;

-- function calls in the target list is supported via fast path
SELECT LEFT(title, 1) FROM articles_hash WHERE author_id = 1


-- top-level union queries are supported through recursive planning

SET client_min_messages to 'NOTICE';

-- unions in subqueries are not supported via fast-path planning
SELECT * FROM (
	(SELECT * FROM articles_hash WHERE author_id = 1)
	UNION
	(SELECT * FROM articles_hash WHERE author_id = 1)) uu
ORDER BY 1, 2
LIMIT 5;


-- Test various filtering options for router plannable check
SET client_min_messages to 'DEBUG2';

-- cannot go through fast-path if there is
-- explicit coercion
SELECT *
	FROM articles_hash
	WHERE author_id = 1::bigint;

-- can go through fast-path if there is
-- implicit coercion
-- This doesn't work see the related issue
-- reported https://github.com/citusdata/citus/issues/2605
-- SELECT *
--	FROM articles_hash
--	WHERE author_id = 1.0;

SELECT *
	FROM articles_hash
	WHERE author_id = 68719476736; -- this is bigint

-- cannot go through fast-path due to
-- multiple filters on the dist. key
SELECT *
	FROM articles_hash
	WHERE author_id = 1 and author_id >= 1;

-- cannot go through fast-path due to
-- multiple filters on the dist. key
SELECT *
	FROM articles_hash
	WHERE author_id = 1 or id = 1;

-- goes through fast-path planning because
-- the dist. key is ANDed with the rest of the
-- filters
SELECT *
	FROM articles_hash
	WHERE author_id = 1 and (id = 1 or id = 41);

-- this time there is an OR clause which prevents
-- router planning at all
SELECT *
	FROM articles_hash
	WHERE author_id = 1 and id = 1 or id = 41;

-- goes through fast-path planning because
-- the dist. key is ANDed with the rest of the
-- filters
SELECT *
	FROM articles_hash
	WHERE author_id = 1 and (id = random()::int  * 0);

-- not router plannable due to function call on the right side
SELECT *
	FROM articles_hash
	WHERE author_id = (random()::int  * 0 + 1);

-- Citus does not qualify this as a fast-path because
-- dist_key = func()
SELECT *
	FROM articles_hash
	WHERE author_id = abs(-1);

-- Citus does not qualify this as a fast-path because
-- dist_key = func()
SELECT *
	FROM articles_hash
	WHERE 1 = abs(author_id);

-- Citus does not qualify this as a fast-path because
-- dist_key = func()
SELECT *
	FROM articles_hash
	WHERE author_id = abs(author_id - 2);

-- the function is not on the dist. key, so qualify as
-- fast-path
SELECT *
	FROM articles_hash
	WHERE author_id = 1 and (id = abs(id - 2));

-- not router plannable due to is true
SELECT *
	FROM articles_hash
	WHERE (author_id = 1) is true;

-- router plannable, (boolean expression) = true is collapsed to (boolean expression)
SELECT *
	FROM articles_hash
	WHERE (author_id = 1) = true;

-- some more complex quals
SELECT count(*) FROM articles_hash WHERE (author_id = 15) AND (id = 1 OR word_count > 5);
SELECT count(*) FROM articles_hash WHERE (author_id = 15) OR (id = 1 AND word_count > 5);
SELECT count(*) FROM articles_hash WHERE (id = 15) OR (author_id = 1 AND word_count > 5);
SELECT count(*) FROM articles_hash WHERE (id = 15) AND (author_id = 1 OR word_count > 5);
SELECT count(*) FROM articles_hash WHERE (id = 15) AND (author_id = 1 AND (word_count > 5 OR id  = 2));
SELECT count(*) FROM articles_hash WHERE (id = 15) AND (title ilike 'a%' AND (word_count > 5 OR author_id  = 2));
SELECT count(*) FROM articles_hash WHERE (id = 15) AND (title ilike 'a%' AND (word_count > 5 AND author_id  = 2));
SELECT count(*) FROM articles_hash WHERE (id = 15) AND (title ilike 'a%' AND ((word_count > 5 OR title ilike 'b%' ) AND (author_id  = 2 AND word_count > 50)));

-- fast-path router plannable, between operator is on another column
SELECT *
	FROM articles_hash
	WHERE (author_id = 1) and id between 0 and 20;

-- fast-path router plannable, partition column expression is and'ed to rest
SELECT *
	FROM articles_hash
	WHERE (author_id = 1) and (id = 1 or id = 31) and title like '%s';

-- fast-path router plannable, order is changed
SELECT *
	FROM articles_hash
	WHERE (id = 1 or id = 31) and title like '%s' and (author_id = 1);

-- fast-path router plannable
SELECT *
	FROM articles_hash
	WHERE (title like '%s' or title like 'a%') and (author_id = 1);

-- fast-path router plannable
SELECT *
	FROM articles_hash
	WHERE (title like '%s' or title like 'a%') and (author_id = 1) and (word_count < 3000 or word_count > 8000);

-- window functions are supported with fast-path router plannable
SELECT LAG(title, 1) over (ORDER BY word_count) prev, title, word_count
	FROM articles_hash
	WHERE author_id = 5;

SELECT LAG(title, 1) over (ORDER BY word_count) prev, title, word_count
	FROM articles_hash
	WHERE author_id = 5
	ORDER BY word_count DESC;

SELECT id, MIN(id) over (order by word_count)
	FROM articles_hash
	WHERE author_id = 1;

SELECT id, word_count, AVG(word_count) over (order by word_count)
	FROM articles_hash
	WHERE author_id = 1;

SELECT word_count, rank() OVER (PARTITION BY author_id ORDER BY word_count)
	FROM articles_hash
	WHERE author_id = 1;

-- some more tests on complex target lists
SELECT DISTINCT ON (author_id, id) author_id, id,
	MIN(id) over (order by avg(word_count)) * AVG(id * 5.2 + (1.0/max(word_count))) over (order by max(word_count)) as t1,
	count(*) FILTER (WHERE title LIKE 'al%') as cnt_with_filter,
	count(*) FILTER (WHERE '0300030' LIKE '%3%') as cnt_with_filter_2,
	avg(case when id > 2 then char_length(word_count::text) * (id * strpos(word_count::text, '1')) end) as case_cnt,
	COALESCE(strpos(avg(word_count)::text, '1'), 20)
	FROM articles_hash as aliased_table
	WHERE author_id = 1
	GROUP BY author_id, id
	HAVING count(DISTINCT title) > 0
	ORDER BY author_id, id, sum(word_count) - avg(char_length(title)) DESC, COALESCE(array_upper(ARRAY[max(id)],1) * 5,0) DESC;

-- where false queries are router plannable but not fast-path
SELECT *
	FROM articles_hash
	WHERE false;

-- fast-path with false
SELECT *
	FROM articles_hash
	WHERE author_id = 1 and false;

-- fast-path with false
SELECT *
	FROM articles_hash
	WHERE author_id = 1 and 1=0;

SELECT *
	FROM articles_hash
	WHERE null and author_id = 1;

-- we cannot qualify dist_key = X operator Y via
-- fast-path planning
SELECT *
	FROM articles_hash
	WHERE author_id = 1 + 1;

-- where false with immutable function returning false
-- goes through fast-path
SELECT *
	FROM articles_hash a
	WHERE a.author_id = 10 and int4eq(1, 2);

-- partition_column is null clause does not prune out any shards,
-- all shards remain after shard pruning, not router plannable
-- not fast-path router either
SELECT *
	FROM articles_hash a
	WHERE a.author_id is null;

-- partition_column equals to null clause prunes out all shards
-- no shards after shard pruning, router plannable
-- not fast-path router either
SELECT *
	FROM articles_hash a
	WHERE a.author_id = null;

-- union/difference /intersection with where false
-- this query was not originally router plannable, addition of 1=0
-- makes it router plannable but not fast-path
SELECT * FROM (
	SELECT * FROM articles_hash WHERE author_id = 1
	UNION
	SELECT * FROM articles_hash WHERE author_id = 2 and 1=0
) AS combination
ORDER BY id;

-- same with the above, but with WHERE false
SELECT * FROM (
	SELECT * FROM articles_hash WHERE author_id = 1
	UNION
	SELECT * FROM articles_hash WHERE author_id = 2 and 1=0
) AS combination WHERE false
ORDER BY id;

-- window functions with where false
SELECT word_count, rank() OVER (PARTITION BY author_id ORDER BY word_count)
	FROM articles_hash
	WHERE author_id = 1 and 1=0;

-- create a dummy function to be used in filtering
CREATE OR REPLACE FUNCTION someDummyFunction(regclass)
    RETURNS text AS
$$
BEGIN
    RETURN md5($1::text);
END;
$$ LANGUAGE 'plpgsql' IMMUTABLE;

-- we execute the query within a function to consolidate the error messages
-- between different executors
CREATE FUNCTION raise_failed_execution_f_router(query text) RETURNS void AS $$
BEGIN
        EXECUTE query;
        EXCEPTION WHEN OTHERS THEN
        IF SQLERRM LIKE '%failed to execute task%' THEN
                RAISE 'Task failed to execute';
        ELSIF SQLERRM LIKE '%does not exist%' THEN
          RAISE 'Task failed to execute';
        ELSIF SQLERRM LIKE '%could not receive query results%' THEN
          	RAISE 'Task failed to execute';
        END IF;
END;
$$LANGUAGE plpgsql;

SET client_min_messages TO ERROR;
\set VERBOSITY terse

-- fast path router plannable, but errors
SELECT raise_failed_execution_f_router($$
	SELECT * FROM articles_hash
		WHERE
			someDummyFunction('articles_hash') = md5('articles_hash') AND author_id = 1
		ORDER BY
			author_id, id
		LIMIT 5;
$$);

\set VERBOSITY DEFAULT
SET client_min_messages TO DEFAULT;

-- temporarily turn off debug messages before dropping the function
SET client_min_messages TO 'NOTICE';
DROP FUNCTION someDummyFunction(regclass);

SET client_min_messages TO 'DEBUG2';

-- complex query hitting a single shard and a fast-path
SELECT
	count(DISTINCT CASE
			WHEN
				word_count > 100
			THEN
				id
			ELSE
				NULL
			END) as c
	FROM
		articles_hash
	WHERE
		author_id = 5;
-- queries inside transactions can be fast-path router plannable
BEGIN;
SELECT *
	FROM articles_hash
	WHERE author_id = 1
	ORDER BY id;
END;

-- queries inside read-only transactions can be fast-path router plannable
SET TRANSACTION READ ONLY;
SELECT *
	FROM articles_hash
	WHERE author_id = 1
	ORDER BY id;
END;

-- cursor queries are fast-path router plannable
BEGIN;
DECLARE test_cursor CURSOR FOR
	SELECT *
		FROM articles_hash
		WHERE author_id = 1
		ORDER BY id;
FETCH test_cursor;
FETCH ALL test_cursor;
FETCH test_cursor; -- fetch one row after the last
FETCH BACKWARD test_cursor;
END;

-- queries inside copy can be router plannable
COPY (
	SELECT *
	FROM articles_hash
	WHERE author_id = 1
	ORDER BY id) TO STDOUT;

-- table creation queries inside can be fast-path router plannable
CREATE TEMP TABLE temp_articles_hash as
	SELECT *
	FROM articles_hash
	WHERE author_id = 1
	ORDER BY id;

-- fast-path router plannable queries may include filter for aggregates
SELECT count(*), count(*) FILTER (WHERE id < 3)
	FROM articles_hash
	WHERE author_id = 1;

-- prepare queries can be router plannable
PREPARE author_1_articles as
	SELECT *
	FROM articles_hash
	WHERE author_id = 1;

EXECUTE author_1_articles;
EXECUTE author_1_articles;
EXECUTE author_1_articles;
EXECUTE author_1_articles;
EXECUTE author_1_articles;
EXECUTE author_1_articles;

-- parametric prepare queries can be router plannable
PREPARE author_articles(int) as
	SELECT *
	FROM articles_hash
	WHERE author_id = $1;

EXECUTE author_articles(1);
EXECUTE author_articles(1);
EXECUTE author_articles(1);
EXECUTE author_articles(1);
EXECUTE author_articles(1);
EXECUTE author_articles(1);

EXECUTE author_articles(NULL);
EXECUTE author_articles(NULL);
EXECUTE author_articles(NULL);
EXECUTE author_articles(NULL);
EXECUTE author_articles(NULL);
EXECUTE author_articles(NULL);
EXECUTE author_articles(NULL);

PREPARE author_articles_update(int) AS
	UPDATE articles_hash SET title = 'test' WHERE author_id = $1;

EXECUTE author_articles_update(NULL);
EXECUTE author_articles_update(NULL);
EXECUTE author_articles_update(NULL);
EXECUTE author_articles_update(NULL);
EXECUTE author_articles_update(NULL);
EXECUTE author_articles_update(NULL);
EXECUTE author_articles_update(NULL);

-- queries inside plpgsql functions could be router plannable
CREATE OR REPLACE FUNCTION author_articles_max_id() RETURNS int AS $$
DECLARE
  max_id integer;
BEGIN
	SELECT MAX(id) FROM articles_hash ah
		WHERE author_id = 1
		into max_id;
	return max_id;
END;
$$ LANGUAGE plpgsql;

-- we don't want too many details. though we're omitting
-- "DETAIL:  distribution column value:", we see it acceptable
-- since the query results verifies the correctness
\set VERBOSITY terse

SELECT author_articles_max_id();
SELECT author_articles_max_id();
SELECT author_articles_max_id();
SELECT author_articles_max_id();
SELECT author_articles_max_id();
SELECT author_articles_max_id();

-- queries inside plpgsql functions could be router plannable
CREATE OR REPLACE FUNCTION author_articles_max_id(int) RETURNS int AS $$
DECLARE
  max_id integer;
BEGIN
	SELECT MAX(id) FROM articles_hash ah
		WHERE author_id = $1
		into max_id;
	return max_id;
END;
$$ LANGUAGE plpgsql;
SELECT author_articles_max_id(1);
SELECT author_articles_max_id(1);
SELECT author_articles_max_id(1);
SELECT author_articles_max_id(1);
SELECT author_articles_max_id(1);
SELECT author_articles_max_id(1);

-- check that function returning setof query are router plannable
CREATE OR REPLACE FUNCTION author_articles_id_word_count() RETURNS TABLE(id bigint, word_count int) AS $$
DECLARE
BEGIN
	RETURN QUERY
		SELECT ah.id, ah.word_count
		FROM articles_hash ah
		WHERE author_id = 1;

END;
$$ LANGUAGE plpgsql;

SELECT * FROM author_articles_id_word_count();
SELECT * FROM author_articles_id_word_count();
SELECT * FROM author_articles_id_word_count();
SELECT * FROM author_articles_id_word_count();
SELECT * FROM author_articles_id_word_count();
SELECT * FROM author_articles_id_word_count();

-- check that function returning setof query are router plannable
CREATE OR REPLACE FUNCTION author_articles_id_word_count(int) RETURNS TABLE(id bigint, word_count int) AS $$
DECLARE
BEGIN
	RETURN QUERY
		SELECT ah.id, ah.word_count
		FROM articles_hash ah
		WHERE author_id = $1;

END;
$$ LANGUAGE plpgsql;
SELECT * FROM author_articles_id_word_count(1);
SELECT * FROM author_articles_id_word_count(1);
SELECT * FROM author_articles_id_word_count(1);
SELECT * FROM author_articles_id_word_count(1);
SELECT * FROM author_articles_id_word_count(1);
SELECT * FROM author_articles_id_word_count(1);

\set VERBOSITY default

-- insert .. select via coordinator could also
-- use fast-path queries
PREPARE insert_sel(int, int) AS
INSERT INTO articles_hash
	SELECT * FROM articles_hash WHERE author_id = $2 AND word_count = $1 OFFSET 0;

EXECUTE insert_sel(1,1);
EXECUTE insert_sel(1,1);
EXECUTE insert_sel(1,1);
EXECUTE insert_sel(1,1);
EXECUTE insert_sel(1,1);
EXECUTE insert_sel(1,1);

-- one final interesting preperad statement
-- where one of the filters is on the target list
PREPARE fast_path_agg_filter(int, int) AS
	SELECT
		count(*) FILTER (WHERE word_count=$1)
	FROM
		articles_hash
	WHERE author_id = $2;

EXECUTE fast_path_agg_filter(1,1);
EXECUTE fast_path_agg_filter(2,2);
EXECUTE fast_path_agg_filter(3,3);
EXECUTE fast_path_agg_filter(4,4);
EXECUTE fast_path_agg_filter(5,5);
EXECUTE fast_path_agg_filter(6,6);

-- views internally become subqueries, so not fast-path router query
CREATE VIEW test_view AS
	SELECT * FROM articles_hash WHERE author_id = 1;
SELECT * FROM test_view;

-- materialized views can be created for fast-path router plannable queries
CREATE MATERIALIZED VIEW mv_articles_hash_empty AS
	SELECT * FROM articles_hash WHERE author_id = 1;
SELECT * FROM mv_articles_hash_empty;


SELECT id
	FROM articles_hash
	WHERE author_id = 1;

INSERT INTO articles_hash VALUES (51, 1, 'amateus', 1814), (52, 1, 'second amateus', 2824);

-- verify insert is successfull (not router plannable and executable)
SELECT id
	FROM articles_hash
	WHERE author_id = 1;

SET client_min_messages to 'NOTICE';

-- finally, some tests with partitioned tables
CREATE TABLE collections_list (
	key bigint,
	ts timestamptz,
	collection_id integer,
	value numeric
) PARTITION BY LIST (collection_id );

CREATE TABLE collections_list_1
	PARTITION OF collections_list (key, ts, collection_id, value)
	FOR VALUES IN ( 1 );

CREATE TABLE collections_list_2
	PARTITION OF collections_list (key, ts, collection_id, value)
	FOR VALUES IN ( 2 );

-- we don't need many shards
SET citus.shard_count TO 2;

SELECT create_distributed_table('collections_list', 'key');
INSERT INTO collections_list SELECT i % 10, now(), (i % 2) + 1, i*i FROM generate_series(0, 50)i;

SET client_min_messages to 'DEBUG2';

SELECT count(*) FROM collections_list WHERE key = 4;
SELECT count(*) FROM collections_list_1 WHERE key = 4;
SELECT count(*) FROM collections_list_2 WHERE key = 4;
UPDATE collections_list SET value = 15 WHERE key = 4;
SELECT count(*) FILTER (where value = 15) FROM collections_list WHERE key = 4;
SELECT count(*) FILTER (where value = 15) FROM collections_list_1 WHERE key = 4;
SELECT count(*) FILTER (where value = 15) FROM collections_list_2 WHERE key = 4;

SET client_min_messages to 'NOTICE';

DROP FUNCTION author_articles_max_id();
DROP FUNCTION author_articles_id_word_count();

DROP MATERIALIZED VIEW mv_articles_hash_empty;
DROP MATERIALIZED VIEW mv_articles_hash_data;

DROP TABLE articles_hash;
DROP TABLE authors_hash;
DROP TABLE authors_range;
DROP TABLE authors_reference;
DROP TABLE company_employees;
DROP TABLE articles_range;
DROP TABLE articles_append;
DROP TABLE collections_list;

RESET search_path;
DROP SCHEMA fast_path_router_select CASCADE;
