MDEV-24395 Atomic DROP TRIGGER

The purpose of this task is to ensure that DROP TRIGGER is atomic.

Description of how atomic drop trigger works:

Logging of DROP TRIGGER
    Log the following information:
    db
    table name
    trigger name
    xid /* Used to check if query was already logged to binary log */
    initial length of the .TRG file
    query if there is space for it, if not log a zero length query.

Recovery operations:
- Delete if exists 'database/trigger_name.TRN~'
  - If this file existed, it means that we crashed before the trigger
    was deleted and there is nothing else to do.
- Get length of .TRG file
  - If file length is unchanged, trigger was not dropped. Nothing else to
    do.
- Log original query to binary, if it was stored in the ddl log. If it was
  not stored (long query string), log the following query to binary log:
  use `database` ; DROP TRIGGER IF EXISTS `trigger_name`
  /* generated by ddl log */;

Other things:
- Added trigger name and DDL_LOG_STATE to drop_trigger()
  Trigger name was added to make the interface more consistent and
  more general.

1 files changed, 6 insertions, 1 deletions

diff --git a/sql/sql_trigger.h b/sql/sql_trigger.h
index 040d8eba989..f0eae8c348f 100644
--- a/sql/sql_trigger.h
+++ b/sql/sql_trigger.h
@@ -28,6 +28,7 @@ class sp_name;
 class Query_tables_list;
 struct TABLE_LIST;
 class Query_tables_list;
+typedef struct st_ddl_log_state DDL_LOG_STATE;
 
 /** Event on which trigger is invoked. */
 enum trg_event_type
@@ -220,7 +221,9 @@ public:
   ~Table_triggers_list();
 
   bool create_trigger(THD *thd, TABLE_LIST *table, String *stmt_query);
-  bool drop_trigger(THD *thd, TABLE_LIST *table, String *stmt_query);
+  bool drop_trigger(THD *thd, TABLE_LIST *table,
+                    LEX_CSTRING *sp_name,
+                    String *stmt_query, DDL_LOG_STATE *ddl_log_state);
   bool process_triggers(THD *thd, trg_event_type event,
                         trg_action_time_type time_type,
                         bool old_row_is_record1);
@@ -324,6 +327,8 @@ bool load_table_name_for_trigger(THD *thd,
                                  const LEX_CSTRING *trn_path,
                                  LEX_CSTRING *tbl_name);
 bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create);
+bool rm_trigname_file(char *path, const LEX_CSTRING *db,
+                      const LEX_CSTRING *trigger_name, myf MyFlags);
 
 extern const char * const TRG_EXT;
 extern const char * const TRN_EXT;