Merge pull request #610 from citusdata/501_single_worker_queries

Refactor multi_planner to create router plan directly

src/backend/distributed/planner/multi_planner.c

@@ -72,15 +72,8 @@ MultiPlan *
 CreatePhysicalPlan(Query *parse)
 {
 	Query *parseCopy = copyObject(parse);
-	MultiPlan *physicalPlan = NULL;
+	MultiPlan *physicalPlan = MultiRouterPlanCreate(parseCopy, TaskExecutorType);
-	bool routerPlannable = MultiRouterPlannableQuery(parseCopy, TaskExecutorType);
+	if (physicalPlan == NULL)
-	if (routerPlannable)
-	{
-		ereport(DEBUG2, (errmsg("Creating router plan")));
-		physicalPlan = MultiRouterPlanCreate(parseCopy);
-		CheckNodeIsDumpable((Node *) physicalPlan);
-	}
-	else
 	{
 		/* Create and optimize logical plan */
 		MultiTreeRoot *logicalPlan = MultiLogicalPlanCreate(parseCopy);

src/backend/distributed/planner/multi_router_planner.c

@@ -70,19 +70,20 @@ static Oid ExtractFirstDistributedTableId(Query *query);
 static Const * ExtractInsertPartitionValue(Query *query, Var *partitionColumn);
 static Task * RouterSelectTask(Query *query);
 static Job * RouterQueryJob(Query *query, Task *task);
+static bool MultiRouterPlannableQuery(Query *query, MultiExecutorType taskExecutorType);
 static bool ColumnMatchExpressionAtTopLevelConjunction(Node *node, Var *column);
 static void SetRangeTablesInherited(Query *query);
 
 
 /*
- * MultiRouterPlanCreate creates a physical plan for given router plannable query.
+ * MultiRouterPlanCreate creates a physical plan for given query. The created plan is
- * Created plan is either a modify task that changes a single shard, or a router task
+ * either a modify task that changes a single shard, or a router task that returns
- * that returns query results from a single shard. Supported modify queries
+ * query results from a single shard. Supported modify queries (insert/update/delete)
- * (insert/update/delete) are router plannble by default. The caller is expected to call
+ * are router plannable by default. If query is not router plannable then the function
- * MultiRouterPlannableQuery to see if the query is router plannable for select queries.
+ * returns NULL.
  */
 MultiPlan *
-MultiRouterPlanCreate(Query *query)
+MultiRouterPlanCreate(Query *query, MultiExecutorType taskExecutorType)
 {
 	Task *task = NULL;
 	Job *job = NULL;
@@ -90,6 +91,14 @@ MultiRouterPlanCreate(Query *query)
 	CmdType commandType = query->commandType;
 	bool modifyTask = false;
 
+	bool routerPlannable = MultiRouterPlannableQuery(query, taskExecutorType);
+	if (!routerPlannable)
+	{
+		return NULL;
+	}
+
+	ereport(DEBUG2, (errmsg("Creating router plan")));
+
 	if (commandType == CMD_INSERT || commandType == CMD_UPDATE ||
 		commandType == CMD_DELETE)
 	{

src/include/distributed/multi_router_planner.h

@@ -30,8 +30,8 @@
 #define UPSERT_ALIAS "citus_table_alias"
 #endif
 
-extern MultiPlan * MultiRouterPlanCreate(Query *query);
+extern MultiPlan * MultiRouterPlanCreate(Query *query,
+										 MultiExecutorType taskExecutorType);
 extern void ErrorIfModifyQueryNotSupported(Query *queryTree);
-extern bool MultiRouterPlannableQuery(Query *query, MultiExecutorType taskExecutorType);
 
 #endif /* MULTI_ROUTER_PLANNER_H */