Add EXPLAIN regression test with subplans

src/test/regress/expected/multi_explain.out

@@ -713,6 +713,7 @@ Limit
                                                               Sort Key: events.event_time DESC
                                                               ->  Seq Scan on events_1400029 events
                                                                     Filter: (composite_id = users.composite_id)
+RESET citus.subquery_pushdown;
 -- Test all tasks output
 SET citus.explain_all_tasks TO on;
 EXPLAIN (COSTS FALSE)
@@ -1115,3 +1116,75 @@ Custom Scan (Citus INSERT ... SELECT via coordinator)
         ->  Append
               ->  Function Scan on generate_series s
               ->  Function Scan on generate_series s_1
+-- explain with recursive planning
+EXPLAIN (COSTS OFF, VERBOSE true)
+WITH keys AS (
+  SELECT DISTINCT l_orderkey FROM lineitem_hash_part
+),
+series AS (
+  SELECT s FROM generate_series(1,10) s
+)
+SELECT l_orderkey FROM series JOIN keys ON (s = l_orderkey)
+ORDER BY s;
+Custom Scan (Citus Router)
+  Output: remote_scan.l_orderkey
+  ->  Distributed Subplan 54_1
+        ->  HashAggregate
+              Output: remote_scan.l_orderkey
+              Group Key: remote_scan.l_orderkey
+              ->  Custom Scan (Citus Real-Time)
+                    Output: remote_scan.l_orderkey
+                    Task Count: 4
+                    Tasks Shown: One of 4
+                    ->  Task
+                          Node: host=localhost port=57637 dbname=regression
+                          ->  HashAggregate
+                                Output: l_orderkey
+                                Group Key: lineitem_hash_part.l_orderkey
+                                ->  Seq Scan on public.lineitem_hash_part_360038 lineitem_hash_part
+                                      Output: l_orderkey, l_partkey, l_suppkey, l_linenumber, l_quantity, l_extendedprice, l_discount, l_tax, l_returnflag, l_linestatus, l_shipdate, l_commitdate, l_receiptdate, l_shipinstruct, l_shipmode, l_comment
+  ->  Distributed Subplan 54_2
+        ->  Function Scan on pg_catalog.generate_series s
+              Output: s
+              Function Call: generate_series(1, 10)
+  Task Count: 1
+  Tasks Shown: All
+  ->  Task
+        Node: host=localhost port=57638 dbname=regression
+        ->  Merge Join
+              Output: intermediate_result_1.l_orderkey, intermediate_result.s
+              Merge Cond: (intermediate_result.s = intermediate_result_1.l_orderkey)
+              ->  Sort
+                    Output: intermediate_result.s
+                    Sort Key: intermediate_result.s
+                    ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result
+                          Output: intermediate_result.s
+                          Function Call: read_intermediate_result('54_2'::text, 'binary'::citus_copy_format)
+              ->  Sort
+                    Output: intermediate_result_1.l_orderkey
+                    Sort Key: intermediate_result_1.l_orderkey
+                    ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result_1
+                          Output: intermediate_result_1.l_orderkey
+                          Function Call: read_intermediate_result('54_1'::text, 'binary'::citus_copy_format)
+SELECT true AS valid FROM explain_json($$
+  WITH result AS (
+    SELECT l_quantity, count(*) count_quantity FROM lineitem
+	GROUP BY l_quantity ORDER BY count_quantity, l_quantity
+  ),
+  series AS (
+    SELECT s FROM generate_series(1,10) s
+  )
+  SELECT * FROM result JOIN series ON (s = count_quantity) JOIN orders_hash_part ON (s = o_orderkey)
+$$);
+t
+SELECT true AS valid FROM explain_xml($$
+  WITH result AS (
+    SELECT l_quantity, count(*) count_quantity FROM lineitem
+	GROUP BY l_quantity ORDER BY count_quantity, l_quantity
+  ),
+  series AS (
+    SELECT s FROM generate_series(1,10) s
+  )
+  SELECT * FROM result JOIN series ON (s = l_quantity) JOIN orders_hash_part ON (s = o_orderkey)
+$$);
+t

src/test/regress/expected/multi_explain_0.out

@@ -713,6 +713,7 @@ Limit
                                                               Sort Key: events.event_time DESC
                                                               ->  Seq Scan on events_1400029 events
                                                                     Filter: (composite_id = users.composite_id)
+RESET citus.subquery_pushdown;
 -- Test all tasks output
 SET citus.explain_all_tasks TO on;
 EXPLAIN (COSTS FALSE)
@@ -1115,3 +1116,75 @@ Custom Scan (Citus INSERT ... SELECT via coordinator)
         ->  Append
               ->  Function Scan on generate_series s
               ->  Function Scan on generate_series s_1
+-- explain with recursive planning
+EXPLAIN (COSTS OFF, VERBOSE true)
+WITH keys AS (
+  SELECT DISTINCT l_orderkey FROM lineitem_hash_part
+),
+series AS (
+  SELECT s FROM generate_series(1,10) s
+)
+SELECT l_orderkey FROM series JOIN keys ON (s = l_orderkey)
+ORDER BY s;
+Custom Scan (Citus Router)
+  Output: remote_scan.l_orderkey
+  ->  Distributed Subplan 54_1
+        ->  HashAggregate
+              Output: remote_scan.l_orderkey
+              Group Key: remote_scan.l_orderkey
+              ->  Custom Scan (Citus Real-Time)
+                    Output: remote_scan.l_orderkey
+                    Task Count: 4
+                    Tasks Shown: One of 4
+                    ->  Task
+                          Node: host=localhost port=57637 dbname=regression
+                          ->  HashAggregate
+                                Output: l_orderkey
+                                Group Key: lineitem_hash_part.l_orderkey
+                                ->  Seq Scan on public.lineitem_hash_part_360038 lineitem_hash_part
+                                      Output: l_orderkey, l_partkey, l_suppkey, l_linenumber, l_quantity, l_extendedprice, l_discount, l_tax, l_returnflag, l_linestatus, l_shipdate, l_commitdate, l_receiptdate, l_shipinstruct, l_shipmode, l_comment
+  ->  Distributed Subplan 54_2
+        ->  Function Scan on pg_catalog.generate_series s
+              Output: s
+              Function Call: generate_series(1, 10)
+  Task Count: 1
+  Tasks Shown: All
+  ->  Task
+        Node: host=localhost port=57638 dbname=regression
+        ->  Merge Join
+              Output: intermediate_result_1.l_orderkey, intermediate_result.s
+              Merge Cond: (intermediate_result.s = intermediate_result_1.l_orderkey)
+              ->  Sort
+                    Output: intermediate_result.s
+                    Sort Key: intermediate_result.s
+                    ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result
+                          Output: intermediate_result.s
+                          Function Call: read_intermediate_result('54_2'::text, 'binary'::citus_copy_format)
+              ->  Sort
+                    Output: intermediate_result_1.l_orderkey
+                    Sort Key: intermediate_result_1.l_orderkey
+                    ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result_1
+                          Output: intermediate_result_1.l_orderkey
+                          Function Call: read_intermediate_result('54_1'::text, 'binary'::citus_copy_format)
+SELECT true AS valid FROM explain_json($$
+  WITH result AS (
+    SELECT l_quantity, count(*) count_quantity FROM lineitem
+	GROUP BY l_quantity ORDER BY count_quantity, l_quantity
+  ),
+  series AS (
+    SELECT s FROM generate_series(1,10) s
+  )
+  SELECT * FROM result JOIN series ON (s = count_quantity) JOIN orders_hash_part ON (s = o_orderkey)
+$$);
+t
+SELECT true AS valid FROM explain_xml($$
+  WITH result AS (
+    SELECT l_quantity, count(*) count_quantity FROM lineitem
+	GROUP BY l_quantity ORDER BY count_quantity, l_quantity
+  ),
+  series AS (
+    SELECT s FROM generate_series(1,10) s
+  )
+  SELECT * FROM result JOIN series ON (s = l_quantity) JOIN orders_hash_part ON (s = o_orderkey)
+$$);
+t

src/test/regress/sql/multi_explain.sql

@@ -356,6 +356,8 @@ ORDER BY
 LIMIT
 	10;
 
+RESET citus.subquery_pushdown;
+
 -- Test all tasks output
 SET citus.explain_all_tasks TO on;
 
@@ -519,3 +521,36 @@ EXPLAIN (COSTS OFF)
 INSERT INTO lineitem_hash_part
 ( SELECT s FROM generate_series(1,5) s) UNION
 ( SELECT s FROM generate_series(5,10) s);
+
+-- explain with recursive planning
+EXPLAIN (COSTS OFF, VERBOSE true)
+WITH keys AS (
+  SELECT DISTINCT l_orderkey FROM lineitem_hash_part
+),
+series AS (
+  SELECT s FROM generate_series(1,10) s
+)
+SELECT l_orderkey FROM series JOIN keys ON (s = l_orderkey)
+ORDER BY s;
+
+SELECT true AS valid FROM explain_json($$
+  WITH result AS (
+    SELECT l_quantity, count(*) count_quantity FROM lineitem
+	GROUP BY l_quantity ORDER BY count_quantity, l_quantity
+  ),
+  series AS (
+    SELECT s FROM generate_series(1,10) s
+  )
+  SELECT * FROM result JOIN series ON (s = count_quantity) JOIN orders_hash_part ON (s = o_orderkey)
+$$);
+
+SELECT true AS valid FROM explain_xml($$
+  WITH result AS (
+    SELECT l_quantity, count(*) count_quantity FROM lineitem
+	GROUP BY l_quantity ORDER BY count_quantity, l_quantity
+  ),
+  series AS (
+    SELECT s FROM generate_series(1,10) s
+  )
+  SELECT * FROM result JOIN series ON (s = l_quantity) JOIN orders_hash_part ON (s = o_orderkey)
+$$);