Use CMDTAG_SELECT_COMPAT

CMDTAG_SELECT exists in PG12 hence defining a MACRO such as
CMDTAG_SELECT -> "SELECT" is not possible. I chose CMDTAG_SELECT_COMPAT
because with the COMPAT suffix it is explicit that it maps to different
things in different versions and also has a less chance of mapping
something irrevelant. For example if we used SELECT as a macro, then it
would map every SELECT to whatever it is mapping to, which might have
unexpected/undesired behaviour.

src/backend/distributed/executor/multi_executor.c

@@ -628,9 +628,10 @@ ExecutePlanIntoDestReceiver(PlannedStmt *queryPlan, ParamListInfo params,
 	/* don't display the portal in pg_cursors, it is for internal use only */
 	portal->visible = false;
 
-	PortalDefineQuerySelectCompat(portal,
+	PortalDefineQuery(portal,
 					  NULL,
 					  "",
+					  CMDTAG_SELECT_COMPAT,
 					  list_make1(queryPlan),
 					  NULL);
 

src/backend/distributed/executor/partitioned_intermediate_results.c

@@ -266,7 +266,8 @@ StartPortalForQueryExecution(const char *queryString)
 	/* don't display the portal in pg_cursors, it is for internal use only */
 	portal->visible = false;
 
-	PortalDefineQuerySelectCompat(portal, NULL, queryString, list_make1(queryPlan), NULL);
+	PortalDefineQuery(portal, NULL, queryString, CMDTAG_SELECT_COMPAT, list_make1(
+						  queryPlan), NULL);
 	int eflags = 0;
 	PortalStart(portal, NULL, eflags, GetActiveSnapshot());
 

src/backend/distributed/transaction/transaction_recovery.c

@@ -95,7 +95,8 @@ LogTransactionRecord(int32 groupId, char *transactionName)
 	values[Anum_pg_dist_transaction_gid - 1] = CStringGetTextDatum(transactionName);
 
 	/* open transaction relation and insert new tuple */
-	Relation pgDistTransaction = table_open(DistTransactionRelationId(), RowExclusiveLock);
+	Relation pgDistTransaction = table_open(DistTransactionRelationId(),
+											RowExclusiveLock);
 
 	TupleDesc tupleDescriptor = RelationGetDescr(pgDistTransaction);
 	HeapTuple heapTuple = heap_form_tuple(tupleDescriptor, values, isNulls);

src/include/distributed/version_compat.h

@@ -34,10 +34,8 @@
 #define pg_plan_query_compat(p, q, c, b) pg_plan_query(p, q, c, b)
 #define planner_compat(p, c, b) planner(p, NULL, c, b)
 #define standard_planner_compat(a, c, d) standard_planner(a, NULL, c, d)
-#define PortalDefineQuerySelectCompat(a, b, c, d, e) PortalDefineQuery(a, b, c, \
-																	   CMDTAG_SELECT, d, \
-																	   e)
 #define getOwnedSequencesCompat(a, b) getOwnedSequences(a)
+#define CMDTAG_SELECT_COMPAT CMDTAG_SELECT
 #define ExplainOnePlanCompat(a, b, c, d, e, f, g) ExplainOnePlan(a, b, c, d, e, f, g, \
 																 NULL)
 #define varoattno varattnosyn
@@ -51,8 +49,7 @@
 #define pg_plan_query_compat(p, q, c, b) pg_plan_query(p, c, b)
 #define planner_compat(p, c, b) planner(p, c, b)
 #define standard_planner_compat(a, c, d) standard_planner(a, c, d)
-#define PortalDefineQuerySelectCompat(a, b, c, d, e) PortalDefineQuery(a, b, c, "SELECT", \
+#define CMDTAG_SELECT_COMPAT "SELECT"
-																	   d, e)
 #define getOwnedSequencesCompat(a, b) getOwnedSequences(a, b)
 #define ExplainOnePlanCompat(a, b, c, d, e, f, g) ExplainOnePlan(a, b, c, d, e, f, g)
 #define Set_ptr_value(a, b) ((a)->data.ptr_value = (b))