Added view repair hook in RTE, dependency check hook during Alter table

Signed-off-by: Rahul Parande <[email protected]>

Author: Rahul Parande

src/backend/commands/tablecmds.c

@@ -138,6 +138,7 @@ InvokePreDropColumnHook_type InvokePreDropColumnHook = NULL;
 check_extended_attoptions_hook_type check_extended_attoptions_hook = NULL;
 find_attr_by_name_from_column_def_list_hook_type
 	find_attr_by_name_from_column_def_list_hook = NULL;
+object_dependency_hook_type object_dependency_hook = NULL;
 
 /*
  * State information for ALTER TABLE
@@ -13678,12 +13679,21 @@ RememberAllDependentForRebuilding(AlteredTableInfo *tab, AlterTableType subtype,
 				 * function bodies.  FIXME someday.
 				 */
 				if (subtype == AT_AlterColumnType)
+				{
+					ObjectAddress columnAddr;
+					columnAddr.classId = RelationRelationId;
+					columnAddr.objectId = RelationGetRelid(rel);
+					columnAddr.objectSubId = attnum;
+
+					if (object_dependency_hook && (*object_dependency_hook)(&foundObject, &columnAddr))
+						continue;
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("cannot alter type of a column used by a view or rule"),
 							 errdetail("%s depends on column \"%s\"",
 									   getObjectDescription(&foundObject, false),
 									   colName)));
+				}
 				break;
 
 			case TriggerRelationId:

src/backend/parser/parse_relation.c

@@ -107,6 +107,7 @@ static bool rte_visible_if_lateral(ParseState *pstate, RangeTblEntry *rte);
 static bool rte_visible_if_qualified(ParseState *pstate, RangeTblEntry *rte);
 static bool isQueryUsingTempRelation_walker(Node *node, void *context);
 
+range_table_entry_hook_type range_table_entry_hook = NULL;
 
 /*
  * refnameNamespaceItem
@@ -1522,6 +1523,9 @@ addRangeTableEntry(ParseState *pstate,
 	rte->rtekind = RTE_RELATION;
 	rte->alias = alias;
 
+	if (range_table_entry_hook)
+		(*range_table_entry_hook)(pstate, relation, rte);
+
 	/*
 	 * Identify the type of lock we'll need on this relation.  It's not the
 	 * query's target table (that case is handled elsewhere), so we need

src/include/commands/tablecmds.h

@@ -122,4 +122,9 @@ typedef int (*find_attr_by_name_from_column_def_list_hook_type) (
 extern PGDLLEXPORT find_attr_by_name_from_column_def_list_hook_type
 	find_attr_by_name_from_column_def_list_hook;
 
+typedef bool (*object_dependency_hook_type)(const ObjectAddress *depender, 
+											const ObjectAddress *referenced);
+
+extern PGDLLEXPORT object_dependency_hook_type object_dependency_hook;
+
 #endif							/* TABLECMDS_H */

src/include/parser/parse_relation.h

@@ -131,4 +131,11 @@ typedef int (*find_attr_by_name_from_relation_hook_type) (
 extern PGDLLEXPORT find_attr_by_name_from_relation_hook_type
 	find_attr_by_name_from_relation_hook;
 
+typedef void (*range_table_entry_hook_type)(ParseState *pstate, 
+                                            RangeVar *relation, 
+                                            RangeTblEntry *rte);
+
+/* Hook for plugins to take action after relation open */
+extern PGDLLEXPORT range_table_entry_hook_type range_table_entry_hook;
+
 #endif							/* PARSE_RELATION_H */