Remove the unnecessary return statements (#258)

This commit also fixes some typos.

columnar/src/backend/columnar/columnar_customscan.c

@@ -859,7 +859,7 @@ ExprReferencesRelid(Expr *expr, Index relid)
  * i)   AND_EXPR:
  *      Take pushdownable args of AND expressions by ignoring the other args.
  * ii)  OR_EXPR:
- *      Ignore the whole OR expression if we cannot exract a pushdownable Expr
+ *      Ignore the whole OR expression if we cannot extract a pushdownable Expr
  *      from one of its args.
  * iii) NOT_EXPR:
  *      Simply ignore NOT expressions since we don't expect to see them before
@@ -949,7 +949,7 @@ ExtractPushdownClause(PlannerInfo *root, RelOptInfo *rel, Node *node)
 			ereport(ColumnarPlannerDebugLevel,
 					(errmsg("columnar planner: cannot push down clause: "
 							"none of the arguments were pushdownable, "
-							"due to the reason(s) given above ")));
+							"due to the reason(s) given above")));
 			return NULL;
 		}
 		else if (npushdownableArgs == 1)

columnar/src/backend/columnar/columnar_planner_hook.c

@@ -96,7 +96,7 @@ static Node *
 AggRefArgsExpressionMutator(Node *node, void *context)
 {
 	if (node == NULL)
-		return false;
+		return NULL;
 
 	Node *previousNode = (Node *) context;
 
@@ -108,16 +108,10 @@ AggRefArgsExpressionMutator(Node *node, void *context)
 		HeapTuple operatorTuple;
 
 		if (list_length(opExprNode->args) != 2)
-		{
 			elog(ERROR, "Aggregation vectorizaion works only on two arguments.");
-			return false;
-		}
 
 		if (CheckOpExprArgumentRules(opExprNode->args))
-		{
 			elog(ERROR, "Unsupported aggregate argument combination.");
-			return false;
-		}
 
 		operatorTuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(opExprNode->opno));
 		operatorForm = (Form_pg_operator) GETSTRUCT(operatorTuple);
@@ -126,9 +120,7 @@ AggRefArgsExpressionMutator(Node *node, void *context)
 
 		Oid vectorizedProcedureOid;
 		if (!GetVectorizedProcedureOid(procedureOid, &vectorizedProcedureOid))
-		{
 			elog(ERROR, "Vectorized aggregate not found.");
-		}
 
 		opExprNode->opfuncid = vectorizedProcedureOid;
 
@@ -137,10 +129,7 @@ AggRefArgsExpressionMutator(Node *node, void *context)
 
 	/* This should handle aggregates that have non var(column) as argument*/
 	if (previousNode != NULL && IsA(previousNode, TargetEntry) && !IsA(node, Var))
-	{
-		elog(ERROR, "Vectorized Aggregates accepts accepts only valid column argument");
-		return false;
-	}
+		elog(ERROR, "Vectorized Aggregates accept only valid column argument");
 
 	return expression_tree_mutator(node, AggRefArgsExpressionMutator, (void *) node);
 }
@@ -149,7 +138,7 @@ static Node *
 ExpressionMutator(Node *node, void *context)
 {
 	if (node == NULL)
-		return false;
+		return NULL;
 
 	if (IsA(node, Aggref))
 	{
@@ -402,4 +391,4 @@ void columnar_planner_init(void)
 	columnar_register_aggregator_node();
 #endif
 	columnar_register_indexscan_node();
-}
+}

columnar/src/test/regress/expected/columnar_aggregates_2.out

@@ -215,7 +215,7 @@ DETAIL:  Unsupported aggregate argument combination.
 -- Vectorized Aggregates accepts only non-const values.
 EXPLAIN (verbose, costs off, timing off, summary off) SELECT COUNT(1) FROM t_mixed;
 DEBUG:  Query can't be vectorized. Falling back to original execution.
-DETAIL:  Vectorized Aggregates accepts accepts only valid column argument
+DETAIL:  Vectorized Aggregates accept only valid column argument
                                 QUERY PLAN                                
 --------------------------------------------------------------------------
  Aggregate
@@ -242,7 +242,7 @@ EXPLAIN (verbose, costs off, timing off, summary off) SELECT COUNT(DISTINCT a) F
 -- Vectorized aggregate doesn't accept function as argument
 EXPLAIN (verbose, costs off, timing off, summary off) SELECT SUM(length(b::text)) FROM t_mixed;
 DEBUG:  Query can't be vectorized. Falling back to original execution.
-DETAIL:  Vectorized Aggregates accepts accepts only valid column argument
+DETAIL:  Vectorized Aggregates accept only valid column argument
                      QUERY PLAN                     
 ----------------------------------------------------
  Aggregate