citus/src/test/regress/sql/multi_explain.sql

--
-- MULTI_EXPLAIN
--

ALTER SEQUENCE pg_catalog.pg_dist_shardid_seq RESTART 570000;

-- print major version to make version-specific tests clear
SELECT substring(version(), '\d+\.\d+') AS major_version;

\a\t

SET citus.task_executor_type TO 'real-time';
SET citus.explain_distributed_queries TO on;

-- Function that parses explain output as JSON
CREATE FUNCTION explain_json(query text)
RETURNS jsonb
AS $BODY$
DECLARE
  result jsonb;
BEGIN
  EXECUTE format('EXPLAIN (FORMAT JSON) %s', query) INTO result;
  RETURN result;
END;
$BODY$ LANGUAGE plpgsql;

-- Function that parses explain output as XML
CREATE FUNCTION explain_xml(query text)
RETURNS xml
AS $BODY$
DECLARE
  result xml;
BEGIN
  EXECUTE format('EXPLAIN (FORMAT XML) %s', query) INTO result;
  RETURN result;
END;
$BODY$ LANGUAGE plpgsql;

-- VACUMM related tables to ensure test outputs are stable
VACUUM ANALYZE lineitem;
VACUUM ANALYZE orders;

-- Test Text format
EXPLAIN (COSTS FALSE, FORMAT TEXT)
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity;

-- Test JSON format
EXPLAIN (COSTS FALSE, FORMAT JSON)
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity;

-- Validate JSON format
SELECT true AS valid FROM explain_json($$
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity$$);

-- Test XML format
EXPLAIN (COSTS FALSE, FORMAT XML)
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity;

-- Validate XML format
SELECT true AS valid FROM explain_xml($$
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity$$);

-- Test YAML format
EXPLAIN (COSTS FALSE, FORMAT YAML)
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity;

-- Test Text format
EXPLAIN (COSTS FALSE, FORMAT TEXT)
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity;

-- Test verbose
EXPLAIN (COSTS FALSE, VERBOSE TRUE)
	SELECT sum(l_quantity) / avg(l_quantity) FROM lineitem;

-- Test join
EXPLAIN (COSTS FALSE)
	SELECT * FROM lineitem
	JOIN orders ON l_orderkey = o_orderkey AND l_quantity < 5.0
	ORDER BY l_quantity LIMIT 10;

-- Test insert
EXPLAIN (COSTS FALSE)
	INSERT INTO lineitem VALUES(1,0);

-- Test update
EXPLAIN (COSTS FALSE)
	UPDATE lineitem
	SET l_suppkey = 12
	WHERE l_orderkey = 1 AND l_partkey = 0;

-- Test delete
EXPLAIN (COSTS FALSE)
	DELETE FROM lineitem
	WHERE l_orderkey = 1 AND l_partkey = 0;

-- Test single-shard SELECT
EXPLAIN (COSTS FALSE)
	SELECT l_quantity FROM lineitem WHERE l_orderkey = 5;

SELECT true AS valid FROM explain_xml($$
	SELECT l_quantity FROM lineitem WHERE l_orderkey = 5$$);

SELECT true AS valid FROM explain_json($$
	SELECT l_quantity FROM lineitem WHERE l_orderkey = 5$$);

-- Test CREATE TABLE ... AS
EXPLAIN (COSTS FALSE)
	CREATE TABLE explain_result AS
	SELECT * FROM lineitem;

-- Test having
EXPLAIN (COSTS FALSE, VERBOSE TRUE)
	SELECT sum(l_quantity) / avg(l_quantity) FROM lineitem
	HAVING sum(l_quantity) > 100;

-- Test having without aggregate
EXPLAIN (COSTS FALSE, VERBOSE TRUE)
	SELECT l_quantity FROM lineitem
	GROUP BY l_quantity
	HAVING l_quantity > (100 * random());

-- Test all tasks output
SET citus.explain_all_tasks TO on;

EXPLAIN (COSTS FALSE)
	SELECT avg(l_linenumber) FROM lineitem WHERE l_orderkey > 9030;

SELECT true AS valid FROM explain_xml($$
	SELECT avg(l_linenumber) FROM lineitem WHERE l_orderkey > 9030$$);

SELECT true AS valid FROM explain_json($$
	SELECT avg(l_linenumber) FROM lineitem WHERE l_orderkey > 9030$$);

-- Test track tracker
SET citus.task_executor_type TO 'task-tracker';
SET citus.explain_all_tasks TO off;

EXPLAIN (COSTS FALSE)
	SELECT avg(l_linenumber) FROM lineitem WHERE l_orderkey > 9030;

-- Test re-partition join
SET citus.large_table_shard_count TO 1;

EXPLAIN (COSTS FALSE)
	SELECT count(*)
	FROM lineitem, orders, customer, supplier_single_shard
	WHERE l_orderkey = o_orderkey
	AND o_custkey = c_custkey
	AND l_suppkey = s_suppkey;

EXPLAIN (COSTS FALSE, FORMAT JSON)
	SELECT count(*)
	FROM lineitem, orders, customer, supplier_single_shard
	WHERE l_orderkey = o_orderkey
	AND o_custkey = c_custkey
	AND l_suppkey = s_suppkey;

SELECT true AS valid FROM explain_json($$
	SELECT count(*)
	FROM lineitem, orders, customer, supplier_single_shard
	WHERE l_orderkey = o_orderkey
	AND o_custkey = c_custkey
	AND l_suppkey = s_suppkey$$);

EXPLAIN (COSTS FALSE, FORMAT XML)
	SELECT count(*)
	FROM lineitem, orders, customer, supplier_single_shard
	WHERE l_orderkey = o_orderkey
	AND o_custkey = c_custkey
	AND l_suppkey = s_suppkey;

SELECT true AS valid FROM explain_xml($$
	SELECT count(*)
	FROM lineitem, orders, customer, supplier
	WHERE l_orderkey = o_orderkey
	AND o_custkey = c_custkey
	AND l_suppkey = s_suppkey$$);

-- make sure that EXPLAIN works without 
-- problems for queries that inlvolves only 
-- reference tables
SELECT true AS valid FROM explain_xml($$
	SELECT count(*)
	FROM nation
	WHERE n_name = 'CHINA'$$);

SELECT true AS valid FROM explain_xml($$
	SELECT count(*)
	FROM nation, supplier
	WHERE nation.n_nationkey = supplier.s_nationkey$$);


EXPLAIN (COSTS FALSE, FORMAT YAML)
	SELECT count(*)
	FROM lineitem, orders, customer, supplier_single_shard
	WHERE l_orderkey = o_orderkey
	AND o_custkey = c_custkey
	AND l_suppkey = s_suppkey;

-- test parallel aggregates
SET parallel_setup_cost=0;
SET parallel_tuple_cost=0;
SET min_parallel_relation_size=0;
SET max_parallel_workers_per_gather=4;

-- ensure local plans display correctly
CREATE TABLE lineitem_clone (LIKE lineitem);
EXPLAIN (COSTS FALSE) SELECT avg(l_linenumber) FROM lineitem_clone;

-- ensure distributed plans don't break
EXPLAIN (COSTS FALSE) SELECT avg(l_linenumber) FROM lineitem;

-- ensure EXPLAIN EXECUTE doesn't crash
PREPARE task_tracker_query AS
	SELECT avg(l_linenumber) FROM lineitem WHERE l_orderkey > 9030;
EXPLAIN (COSTS FALSE) EXECUTE task_tracker_query;

SET citus.task_executor_type TO 'real-time';

PREPARE router_executor_query AS SELECT l_quantity FROM lineitem WHERE l_orderkey = 5;
EXPLAIN EXECUTE router_executor_query;

PREPARE real_time_executor_query AS
	SELECT avg(l_linenumber) FROM lineitem WHERE l_orderkey > 9030;
EXPLAIN (COSTS FALSE) EXECUTE real_time_executor_query;

-- EXPLAIN EXECUTE of parametrized prepared statements is broken, but
-- at least make sure to fail without crashing
PREPARE router_executor_query_param(int) AS SELECT l_quantity FROM lineitem WHERE l_orderkey = $1;
EXPLAIN EXECUTE router_executor_query_param(5);

-- test explain in a transaction with alter table to test we use right connections
BEGIN;

CREATE TABLE explain_table(id int);
SELECT create_distributed_table('explain_table', 'id');

ALTER TABLE explain_table ADD COLUMN value int;

EXPLAIN (COSTS FALSE) SELECT value FROM explain_table WHERE id = 1;

ROLLBACK;

-- Test disable hash aggregate
SET enable_hashagg TO off;
EXPLAIN (COSTS FALSE, FORMAT TEXT)
	SELECT l_quantity, count(*) count_quantity FROM lineitem
	GROUP BY l_quantity ORDER BY count_quantity, l_quantity;

SET enable_hashagg TO on;