Add GUC on distributed execution paths

Author: danolivo

contrib/pg_exchange/hooks.c

@@ -39,7 +39,8 @@ HOOK_Baserel_paths(PlannerInfo *root, RelOptInfo *rel, Index rti,
 	if (prev_set_rel_pathlist_hook)
 		(*prev_set_rel_pathlist_hook) (root, rel, rti, rte);
 
-	add_exchange_paths(root, rel, rti, rte);
+	if (enable_distributed_execution)
+		add_exchange_paths(root, rel, rti, rte);
 }
 
 static bool

contrib/pg_exchange/nodeDistPlanExec.c

@@ -44,7 +44,7 @@ static CustomScanMethods	distplanexec_plan_methods;
 static CustomExecMethods	distplanexec_exec_methods;
 
 char destsName[10] = "DMQ_DESTS";
-char *network_interface;
+bool enable_distributed_execution;
 
 
 static Node *CreateDistPlanExecState(CustomScan *node);

contrib/pg_exchange/nodeDistPlanExec.h

@@ -27,7 +27,7 @@ typedef struct
 } lcontext;
 
 
-extern char *network_interface;
+extern bool enable_distributed_execution;
 extern char destsName[10];
 #define DISTEXECPATHNAME	"DistExecPath"
 

contrib/pg_exchange/pg_exchange.c

@@ -69,10 +69,16 @@ shmem_size(void)
 void
 _PG_init(void)
 {
-	DefineCustomStringVariable("network_interface",
-							   "Set network interface for EXCHANGE communications",
-							   NULL, &network_interface, "lo",
-							   PGC_SUSET, GUC_NOT_IN_SAMPLE, NULL, NULL, NULL);
+	DefineCustomBoolVariable("enable_distributed_execution",
+							 "Use distributed execution.",
+							 NULL,
+							 &enable_distributed_execution,
+							 true,
+							 PGC_USERSET,
+							 GUC_NOT_IN_SAMPLE,
+							 NULL,
+							 NULL,
+							 NULL);
 
 	EXCHANGE_Init_methods();
 	DUMMYSCAN_Init_methods();