use ActivePrimaryNodeList to include coordinator

ActiveReadableWorkerNodeList doesn't include coordinator, however if
coordinator is added as a worker, we should also include that while
planning. The current methods are very easily misusable and this
requires a refactoring to make the distinction between methods that
include coordinator and that don't very explicit as they can introduce
subtle/major bugs pretty easily.

src/backend/distributed/operations/worker_node_manager.c

@@ -319,7 +319,6 @@ ActiveReadableNonCoordinatorNodeCount(void)
 	return liveWorkerCount;
 }
 
-
 /*
  * NodeIsCoordinator returns true if the given node represents the coordinator.
  */

src/backend/distributed/planner/multi_physical_planner.c

@@ -2107,7 +2107,7 @@ BuildMapMergeJob(Query *jobQuery, List *dependentJobList, Var *partitionKey,
 static uint32
 HashPartitionCount(void)
 {
-	uint32 groupCount = ActiveReadableNonCoordinatorNodeCount();
+	uint32 groupCount = list_length(ActiveReadableNodeList());
 	double maxReduceTasksPerNode = MaxRunningTasksPerNode / 2.0;
 
 	uint32 partitionCount = (uint32) rint(groupCount * maxReduceTasksPerNode);
@@ -5717,7 +5717,7 @@ AssignDualHashTaskList(List *taskList)
 	 * if subsequent jobs have a small number of tasks, we won't allocate the
 	 * tasks to the same worker repeatedly.
 	 */
-	List *workerNodeList = ActiveReadableNonCoordinatorNodeList();
+	List *workerNodeList = ActiveReadableNodeList();
 	uint32 workerNodeCount = (uint32) list_length(workerNodeList);
 	uint32 beginningNodeIndex = jobId % workerNodeCount;
 

src/test/regress/expected/coordinator_shouldhaveshards.out

@@ -456,6 +456,7 @@ BEGIN;
 -- copying task
 INSERT INTO dist_table SELECT a + 1 FROM dist_table;
 ROLLBACK;
+SET citus.shard_replication_factor TO 1;
 BEGIN;
 SET citus.shard_replication_factor TO 2;
 CREATE TABLE dist_table1(a int);
@@ -476,11 +477,12 @@ RESET citus.enable_cte_inlining;
 DELETE FROM test;
 DROP TABLE test;
 DROP TABLE dist_table;
+DROP TABLE ref;
+NOTICE:  executing the command locally: DROP TABLE IF EXISTS coordinator_shouldhaveshards.ref_xxxxx CASCADE
+CONTEXT:  SQL statement "SELECT master_drop_all_shards(v_obj.objid, v_obj.schema_name, v_obj.object_name)"
+PL/pgSQL function citus_drop_trigger() line 19 at PERFORM
 DROP SCHEMA coordinator_shouldhaveshards CASCADE;
-NOTICE:  drop cascades to 3 other objects
+NOTICE:  drop cascades to table local
-DETAIL:  drop cascades to table ref
-drop cascades to table ref_1503016
-drop cascades to table local
 SELECT 1 FROM master_set_node_property('localhost', :master_port, 'shouldhaveshards', false);
  ?column?
 ---------------------------------------------------------------------

src/test/regress/expected/follower_single_node.out

@@ -34,6 +34,17 @@ CREATE TABLE local(c int, d int);
 INSERT INTO test VALUES (1, 2), (3, 4), (5, 6), (2, 7), (4, 5);
 INSERT INTO ref VALUES (1, 2), (5, 6), (7, 8);
 INSERT INTO local VALUES (1, 2), (3, 4), (7, 8);
+-- Check repartion joins are supported
+SET citus.enable_repartition_joins TO ON;
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+ x | y | x | y
+---------------------------------------------------------------------
+ 2 | 7 | 1 | 2
+ 4 | 5 | 3 | 4
+ 5 | 6 | 4 | 5
+(3 rows)
+
+RESET citus.enable_repartition_joins;
 -- connect to the follower and check that a simple select query works, the follower
 -- is still in the default cluster and will send queries to the primary nodes
 \c - - - :follower_master_port
@@ -102,15 +113,10 @@ SELECT * FROM ref, local WHERE a = c ORDER BY a;
  7 | 8 | 7 | 8
 (2 rows)
 
--- Check repartion joins are support
-SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-ERROR:  floating-point exception
-DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
 SET citus.enable_repartition_joins TO ON;	
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-ERROR:  floating-point exception
+ERROR:  writing to worker nodes is not currently allowed
-DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+DETAIL:  the database is in recovery mode
-RESET citus.enable_repartition_joins;
 -- Confirm that dummy placements work
 SELECT count(*) FROM test WHERE false;
  count
@@ -226,15 +232,10 @@ SELECT * FROM ref, local WHERE a = c ORDER BY a;
  7 | 8 | 7 | 8
 (2 rows)
 
--- Check repartion joins are support
-SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-ERROR:  floating-point exception
-DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
 SET citus.enable_repartition_joins TO ON;	
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-ERROR:  floating-point exception
+ERROR:  writing to worker nodes is not currently allowed
-DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+DETAIL:  the database is in recovery mode
-RESET citus.enable_repartition_joins;
 -- Confirm that dummy placements work
 SELECT count(*) FROM test WHERE false;
  count

src/test/regress/expected/single_node.out

@@ -101,14 +101,19 @@ SELECT * FROM ref, local WHERE a = c ORDER BY a;
  7 | 8 | 7 | 8
 (2 rows)
 
--- Check repartion joins are support
+-- Check repartion joins are supported
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-ERROR:  floating-point exception
+ERROR:  the query contains a join that requires repartitioning
-DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+HINT:  Set citus.enable_repartition_joins to on to enable repartitioning
 SET citus.enable_repartition_joins TO ON;
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-ERROR:  floating-point exception
+ x | y | x | y
-DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+---------------------------------------------------------------------
+ 2 | 7 | 1 | 2
+ 4 | 5 | 3 | 4
+ 5 | 6 | 4 | 5
+(3 rows)
+
 RESET citus.enable_repartition_joins;
 -- INSERT SELECT router
 BEGIN;

src/test/regress/sql/coordinator_shouldhaveshards.sql

@@ -191,6 +191,7 @@ BEGIN;
 -- copying task
 INSERT INTO dist_table SELECT a + 1 FROM dist_table;
 ROLLBACK;
+SET citus.shard_replication_factor TO 1;
 
 BEGIN;
 SET citus.shard_replication_factor TO 2;
@@ -205,6 +206,7 @@ RESET citus.enable_cte_inlining;
 DELETE FROM test;
 DROP TABLE test;
 DROP TABLE dist_table;
+DROP TABLE ref;
 
 DROP SCHEMA coordinator_shouldhaveshards CASCADE;
 

src/test/regress/sql/follower_single_node.sql

@@ -18,6 +18,11 @@ INSERT INTO test VALUES (1, 2), (3, 4), (5, 6), (2, 7), (4, 5);
 INSERT INTO ref VALUES (1, 2), (5, 6), (7, 8);
 INSERT INTO local VALUES (1, 2), (3, 4), (7, 8);
 
+-- Check repartion joins are supported
+SET citus.enable_repartition_joins TO ON;
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+RESET citus.enable_repartition_joins;
+
 -- connect to the follower and check that a simple select query works, the follower
 -- is still in the default cluster and will send queries to the primary nodes
 \c - - - :follower_master_port
@@ -34,11 +39,8 @@ SELECT count(*) FROM local;
 SELECT * FROM local ORDER BY c;
 SELECT * FROM ref, local WHERE a = c ORDER BY a;
 
--- Check repartion joins are support
-SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
 SET citus.enable_repartition_joins TO ON;	
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-RESET citus.enable_repartition_joins;
 
 -- Confirm that dummy placements work
 SELECT count(*) FROM test WHERE false;
@@ -82,11 +84,8 @@ SELECT count(*) FROM local;
 SELECT * FROM local ORDER BY c;
 SELECT * FROM ref, local WHERE a = c ORDER BY a;
 
--- Check repartion joins are support
-SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
 SET citus.enable_repartition_joins TO ON;	
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
-RESET citus.enable_repartition_joins;
 
 -- Confirm that dummy placements work
 SELECT count(*) FROM test WHERE false;

src/test/regress/sql/single_node.sql

@@ -33,7 +33,7 @@ SELECT count(*) FROM local;
 SELECT * FROM local ORDER BY c;
 SELECT * FROM ref, local WHERE a = c ORDER BY a;
 
--- Check repartion joins are support
+-- Check repartion joins are supported
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
 SET citus.enable_repartition_joins TO ON;
 SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;