phase 2: remove the clutter in utiity_hook.c and some funct renaming

src/backend/distributed/commands/non_main_db_distribute_object_ops.c

@@ -143,25 +143,42 @@ IsCommandToCreateOrDropMainDB(Node *parsetree)
 
 
 /*
- * RunPreprocessMainDBCommand runs the necessary commands for a query, in main
+ * RunPreprocessNonMainDBCommand runs the necessary commands for a query, in main
- * database before query is run on the local node with PrevProcessUtility
+ * database before query is run on the local node with PrevProcessUtility.
+ *
+ * Returns true if previous utility hook needs to be skipped after completing
+ * preprocess phase.
  */
-void
+bool
-RunPreprocessMainDBCommand(Node *parsetree)
+RunPreprocessNonMainDBCommand(Node *parsetree)
 {
-	if (!IsStatementSupportedFromNonMainDb(parsetree))
+	if (IsMainDB || !IsStatementSupportedFromNonMainDb(parsetree))
 	{
-		return;
+		return false;
+	}
+
+	if (IsCommandToCreateOrDropMainDB(parsetree))
+	{
+		/*
+		 * We don't try to send the query to the main database if the CREATE/DROP DATABASE
+		 * command is for the main database itself, this is a very rare case but it's
+		 * exercised by our test suite.
+		 */
+		return false;
 	}
 
 	char *queryString = DeparseTreeNode(parsetree);
 
-	if (IsA(parsetree, CreatedbStmt) ||
+	if (IsA(parsetree, CreatedbStmt) || IsA(parsetree, DropdbStmt))
-		IsA(parsetree, DropdbStmt))
 	{
+		/*
+		 * We always execute CREATE/DROP DATABASE from the main database. There are no
+		 * transactional visibility issues, since these commands are non-transactional.
+		 * And this way we only have to consider one codepath when creating databases.
+		 */
 		IsMainDBCommandInXact = false;
 		RunCitusMainDBQuery((char *) queryString);
-		return;
+		return true;
 	}
 
 	IsMainDBCommandInXact = true;
@@ -184,18 +201,24 @@ RunPreprocessMainDBCommand(Node *parsetree)
 		List *unmarkParams = GetDistObjectOperationParams(parsetree);
 		UnMarkObjectDistributedLocallyFromNonMainDb(unmarkParams);
 	}
+
+	return false;
 }
 
 
 /*
- * RunPostprocessMainDBCommand runs the necessary commands for a query, in main
+ * RunPostprocessNonMainDBCommand runs the necessary commands for a query, in main
- * database after query is run on the local node with PrevProcessUtility
+ * database after query is run on the local node with PrevProcessUtility.
  */
 void
-RunPostprocessMainDBCommand(Node *parsetree)
+RunPostprocessNonMainDBCommand(Node *parsetree)
 {
-	if (IsStatementSupportedFromNonMainDb(parsetree) &&
+	if (IsMainDB || !IsStatementSupportedFromNonMainDb(parsetree))
-		StatementRequiresMarkDistributedGloballyFromNonMainDb(parsetree))
+	{
+		return;
+	}
+
+	if (StatementRequiresMarkDistributedGloballyFromNonMainDb(parsetree))
 	{
 		MarkObjectDistributedGloballyFromNonMainDb(parsetree);
 	}

src/backend/distributed/commands/utility_hook.c

@@ -247,37 +247,26 @@ citus_ProcessUtility(PlannedStmt *pstmt,
 	if (!CitusHasBeenLoaded())
 	{
 		/*
-		 * We always execute CREATE/DROP DATABASE from the main database. There are no
+		 * Process the command via RunPreprocessNonMainDBCommand and
-		 * transactional visibility issues, since these commands are non-transactional.
+		 * RunPostprocessNonMainDBCommand hooks if we're in a non-main database
-		 * And this way we only have to consider one codepath when creating databases.
+		 * and if the command is a node-wide object management command that we
-		 * We don't try to send the query to the main database if the CREATE/DROP DATABASE
+		 * support from non-main databases.
-		 * command is for the main database itself, this is a very rare case but it's
-		 * exercised by our test suite.
 		 */
-		if (!IsMainDB &&
-			!IsCommandToCreateOrDropMainDB(parsetree))
-		{
-			RunPreprocessMainDBCommand(parsetree);
 
-			if (IsA(parsetree, CreatedbStmt) ||
+		bool shouldSkipPrevUtilityHook = RunPreprocessNonMainDBCommand(parsetree);
-				IsA(parsetree, DropdbStmt))
-			{
-				return;
-			}
-		}
 
+		if (!shouldSkipPrevUtilityHook)
+		{
 			/*
 			 * Ensure that utility commands do not behave any differently until CREATE
 			 * EXTENSION is invoked.
 			 */
 			PrevProcessUtility(pstmt, queryString, false, context,
 							   params, queryEnv, dest, completionTag);
-
-		if (!IsMainDB)
-		{
-			RunPostprocessMainDBCommand(parsetree);
 		}
 
+		RunPostprocessNonMainDBCommand(parsetree);
+
 		return;
 	}
 	else if (IsA(parsetree, CallStmt))

src/include/distributed/commands.h

@@ -106,8 +106,8 @@ const DistributeObjectOps * GetDistributeObjectOps(Node *node);
 
 /* functions to support node-wide object management commands from non-main dbs */
 extern bool IsCommandToCreateOrDropMainDB(Node *parsetree);
-extern void RunPreprocessMainDBCommand(Node *parsetree);
+extern bool RunPreprocessNonMainDBCommand(Node *parsetree);
-extern void RunPostprocessMainDBCommand(Node *parsetree);
+extern void RunPostprocessNonMainDBCommand(Node *parsetree);
 
 /*
  * Flags that can be passed to GetForeignKeyOids to indicate