BABEL: Support duplicate trigger name in different databases (yugabyt…

…e#50)

Previously, duplicate trigger name was not allowed in different databases.
But in tsql, different databases can have the same trigger name. Here, we
check if a trigger with the same name is in current database. If not, then the
trigger can be created. And during drop trigger, we modify the pre check
trigger in parsing stage to not throw error, and find the correct trigger to
drop with trigger and database name.

Task:BABEL-3117
Signed-off-by: Zhenye Li <zhenye@amazon.com>
(cherry picked from commit ab122807cfde7a4b33f2ea4fa0017075efbd9487)

src/postgres/src/backend/catalog/objectaddress.c

@@ -950,7 +950,8 @@ static void getOpFamilyIdentity(StringInfo buffer, Oid opfid, List **object,
 								bool missing_ok);
 static void getRelationIdentity(StringInfo buffer, Oid relid, List **object,
 								bool missing_ok);
-
+
+get_trigger_object_address_hook_type  get_trigger_object_address_hook = NULL;
 /*
  * Translate an object name and arguments (as passed by the parser) to an
  * ObjectAddress.
@@ -1034,9 +1035,10 @@ get_object_address(ObjectType objtype, Node *object,
 													   &relation, missing_ok);
 				break;
 			case OBJECT_TRIGGER:
-				if(sql_dialect == SQL_DIALECT_TSQL)
-					address = get_object_address_trigger_tsql(castNode(List, object),
-													   	&relation, missing_ok);
+				if(get_trigger_object_address_hook){
+						address = (*get_trigger_object_address_hook)(castNode(List, object),
+															&relation, missing_ok,false);
+				}
 				else
 					address = get_object_address_relobject(objtype, castNode(List, object),
 													   &relation, missing_ok);
@@ -1573,89 +1575,6 @@ get_object_address_relobject(ObjectType objtype, List *object,
 	*relp = relation;
 	return address;
 }
-
-/*
-* A special case of the get_object_address_relobject() function, specifically
-* for the case of triggers in tsql dialect. We add a pg_trigger lookup to search
-* for the relation that the trigger is associated with, since the relation name
-* is not supplied by the user, and thus not a part of the *object list.
-* TODO: we can use a new hook and use this function for triggers or expand it
-* for all objects in tsql dialect case.
-*/
-ObjectAddress
-get_object_address_trigger_tsql(List *object, Relation *relp,
-							 bool missing_ok)
-{
-	ObjectAddress address;
-	Relation	relation = NULL;
-	const char *depname;
-	Oid			reloid;
-	Relation	tgrel;
-	ScanKeyData		key;
-	SysScanDesc tgscan;
-	HeapTuple	tuple;
-
-	/* Extract name of dependent object. */
-	depname = strVal(llast(object));
-
-	/* 
-	* Get the table name of the trigger from pg_trigger. We know that
-	* trigger names are forced to be unique in the tsql dialect, so we
-	* can rely on searching for trigger name to find the corresponding
-	* relation name.
-	*/
-	tgrel = table_open(TriggerRelationId, AccessShareLock);
-
-	ScanKeyInit(&key,
-					Anum_pg_trigger_tgname,
-					BTEqualStrategyNumber, F_NAMEEQ,
-					CStringGetDatum(depname));
-
-	tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, false,
-									NULL, 1, &key);
-
-	while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
-	{
-		Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
-
-		if (namestrcmp(&(pg_trigger->tgname), depname) == 0)
-		{
-			reloid = OidIsValid(pg_trigger->tgrelid) ? pg_trigger->tgrelid :
-						InvalidOid;
-			relation = RelationIdGetRelation(reloid); 
-			RelationClose(relation);
-		}
-	}
-	systable_endscan(tgscan);
-
-	table_close(tgrel, AccessShareLock);
-	address.classId = TriggerRelationId;
-	address.objectId = relation ?
-		get_trigger_oid(reloid, depname, missing_ok) : InvalidOid;
-	if (!relation && !missing_ok)
-	{
-		ereport(ERROR,
-				(errcode(ERRCODE_UNDEFINED_OBJECT),
-				errmsg("trigger \"%s\" does not exist",
-						depname)));
-	}
-	address.objectSubId = 0;
-
-	/* Avoid relcache leak when object not found. */
-	if (!OidIsValid(address.objectId))
-	{
-		if (relation != NULL)
-			table_close(relation, AccessShareLock);
-
-		relation = NULL;		/* department of accident prevention */
-		return address;
-	}
-
-	/* Done. */
-	*relp = relation;
-	return address;
-}
-
 /*
  * Find the ObjectAddress for an attribute.
  */

src/postgres/src/backend/commands/trigger.c

@@ -234,6 +234,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 	bool		existing_isInternal = false;
 	bool		existing_isClone = false;
 	bool		is_composite_trigger = false;
+	char		*pg_trigger_schema_name;
+	char		*newtrigger_schema_name;
 
 	is_composite_trigger = IsCompositeTrigger(funcoid, stmt->funcname);
 
@@ -943,8 +945,11 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 			while (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
 			{
 				Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
-
-				if (namestrcmp(&(pg_trigger->tgname), trigname) == 0)
+				pg_trigger_schema_name = get_namespace_name(get_rel_namespace(pg_trigger->tgrelid));
+				newtrigger_schema_name = get_namespace_name(get_rel_namespace(RelationGetRelid(rel)));
+
+				if (namestrcmp(&(pg_trigger->tgname), trigname) == 0
+							&& strcasecmp(newtrigger_schema_name, pg_trigger_schema_name) == 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_DUPLICATE_OBJECT),
 							errmsg("trigger \"%s\" already exists in the database",

src/postgres/src/include/catalog/objectaddress.h

@@ -86,7 +86,7 @@ extern struct ArrayType *strlist_to_textarray(List *list);
 
 extern ObjectType get_relkind_objtype(char relkind);
 
-extern ObjectAddress get_object_address_trigger_tsql(List *object,
-							Relation *relp, bool missing_ok);
+typedef ObjectAddress (*get_trigger_object_address_hook_type)(List *object, Relation *relp, bool missing_ok,bool object_from_input);
+extern PGDLLIMPORT get_trigger_object_address_hook_type get_trigger_object_address_hook;
 
 #endif							/* OBJECTADDRESS_H */