Check if we can rename triggers before doing an ALTER TABLE ... RENAME

ALTER TABLE .. RENAME, when used with the inplace algorithm, does: - Do an inplace or online alter to the new definition - Rename to new name - Update triggers. If update triggers would fail, we would rename the table back. The problem with this approach is that the table would have the new definition but the rename would fail. The binary log would also not be updated. The solution to this is to very early check if we can rename triggers and give an error if this would fail. Both ALTER TABLE ... RENAME and RENAME TABLE is fixed. This was implemented by moving the pre-check of rename table in triggers from Table_triggers_list::change_table_name() to Table_triggers_list::prepare_for_rename().

Author: montywi

sql/ddl_log.cc

@@ -1160,6 +1160,7 @@ static int ddl_log_execute_action(THD *thd, MEM_ROOT *mem_root,
  case DDL_RENAME_PHASE_TRIGGER:
  {
  MDL_request mdl_request;
+ TRIGGER_RENAME_PARAM trigger_param;
 
  build_filename_and_delete_tmp_file(to_path, sizeof(to_path),
  &ddl_log_entry->db,
@@ -1195,14 +1196,20 @@ static int ddl_log_execute_action(THD *thd, MEM_ROOT *mem_root,
  error= thd->mdl_context.acquire_lock(&mdl_request, 1);
  /* acquire_locks() should never fail during recovery */
  DBUG_ASSERT(error == 0);
-
+ (void) Table_triggers_list::prepare_for_rename(thd,
+ &trigger_param,
+ &ddl_log_entry->db,
+ &to_table,
+ &to_converted_name,
+ &ddl_log_entry->from_db,
+ &from_table);
  (void) Table_triggers_list::change_table_name(thd,
+ &trigger_param,
  &ddl_log_entry->db,
  &to_table,
  &to_converted_name,
  &ddl_log_entry->from_db,
  &from_table);
-
  thd->mdl_context.release_lock(mdl_request.ticket);
  }
  if (ddl_log_increment_phase_no_lock(entry_pos))
@@ -1726,7 +1733,6 @@ static int ddl_log_execute_action(THD *thd, MEM_ROOT *mem_root,
  }
  break;
  }
- }
  default:
  DBUG_ASSERT(0);
  break;

sql/sql_rename.cc

@@ -1,6 +1,6 @@
 /*
  Copyright (c) 2000, 2013, Oracle and/or its affiliates.
- Copyright (c) 2011, 2013, Monty Program Ab.
+ Copyright (c) 2011, 2021, Monty Program Ab.
 
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
@@ -339,6 +339,7 @@ do_rename(THD *thd, rename_param *param, DDL_LOG_STATE *ddl_log_state,
  int rc= 1;
  handlerton *hton;
  LEX_CSTRING *old_alias, *new_alias;
+ TRIGGER_RENAME_PARAM rename_param;
  DBUG_ENTER("do_rename");
  DBUG_PRINT("enter", ("skip_error: %d", (int) skip_error));
 
@@ -361,6 +362,15 @@ do_rename(THD *thd, rename_param *param, DDL_LOG_STATE *ddl_log_state,
  if (hton->flags & HTON_TABLE_MAY_NOT_EXIST_ON_SLAVE)
  *force_if_exists= 1;
 
+ /* Check if we can rename triggers */
+ if (Table_triggers_list::prepare_for_rename(thd, &rename_param,
+ &ren_table->db,
+ old_alias,
+ &ren_table->table_name,
+ new_db,
+ new_alias))
+ DBUG_RETURN(!skip_error);
+
  thd->replication_flags= 0;
 
  if (ddl_log_rename_table(thd, ddl_log_state, hton,
@@ -379,7 +389,9 @@ do_rename(THD *thd, rename_param *param, DDL_LOG_STATE *ddl_log_state,
 
  debug_crash_here("ddl_log_rename_before_rename_trigger");
 
- if (!(rc= Table_triggers_list::change_table_name(thd, &ren_table->db,
+ if (!(rc= Table_triggers_list::change_table_name(thd,
+ &rename_param,
+ &ren_table->db,
  old_alias,
  &ren_table->table_name,
  new_db,

sql/sql_table.cc

@@ -7058,6 +7058,7 @@ static bool mysql_inplace_alter_table(THD *thd,
  TABLE *altered_table,
  Alter_inplace_info *ha_alter_info,
  MDL_request *target_mdl_request,
+ TRIGGER_RENAME_PARAM *trigger_param,
  Alter_table_ctx *alter_ctx)
 {
  Open_table_context ot_ctx(thd, MYSQL_OPEN_REOPEN | MYSQL_OPEN_IGNORE_KILLED);
@@ -7330,7 +7331,7 @@ static bool mysql_inplace_alter_table(THD *thd,
  */
  DBUG_RETURN(true);
  }
- if (Table_triggers_list::change_table_name(thd,
+ if (Table_triggers_list::change_table_name(thd, trigger_param,
  &alter_ctx->db,
  &alter_ctx->alias,
  &alter_ctx->table_name,
@@ -7343,7 +7344,8 @@ static bool mysql_inplace_alter_table(THD *thd,
  */
  (void) mysql_rename_table(db_type,
  &alter_ctx->new_db, &alter_ctx->new_alias,
- &alter_ctx->db, &alter_ctx->alias, NO_FK_CHECKS);
+ &alter_ctx->db, &alter_ctx->alias,
+ NO_FK_CHECKS);
  DBUG_RETURN(true);
  }
  rename_table_in_stat_tables(thd, &alter_ctx->db, &alter_ctx->alias,
@@ -8849,6 +8851,7 @@ simple_tmp_rename_or_index_change(THD *thd, TABLE_LIST *table_list,
 static bool
 simple_rename_or_index_change(THD *thd, TABLE_LIST *table_list,
  Alter_info::enum_enable_or_disable keys_onoff,
+ TRIGGER_RENAME_PARAM *trigger_param,
  Alter_table_ctx *alter_ctx)
 {
  TABLE *table= table_list->table;
@@ -8895,7 +8898,7 @@ simple_rename_or_index_change(THD *thd, TABLE_LIST *table_list,
  if (mysql_rename_table(old_db_type, &alter_ctx->db, &alter_ctx->table_name,
  &alter_ctx->new_db, &alter_ctx->new_alias, 0))
  error= -1;
- else if (Table_triggers_list::change_table_name(thd,
+ else if (Table_triggers_list::change_table_name(thd, trigger_param,
  &alter_ctx->db,
  &alter_ctx->alias,
  &alter_ctx->table_name,
@@ -9080,6 +9083,7 @@ bool mysql_alter_table(THD *thd, const LEX_CSTRING *new_db,
  MDL_request target_mdl_request;
  MDL_ticket *mdl_ticket= 0;
  Alter_table_prelocking_strategy alter_prelocking_strategy;
+ TRIGGER_RENAME_PARAM trigger_param;
  DBUG_ENTER("mysql_alter_table");
 
  /*
@@ -9504,6 +9508,16 @@ do_continue:;
  create_info))
  DBUG_RETURN(true);
 
+ /* Check if rename of triggers are supported */
+ if (alter_ctx.is_table_renamed() &&
+ Table_triggers_list::prepare_for_rename(thd, &trigger_param,
+ &alter_ctx.db,
+ &alter_ctx.alias,
+ &alter_ctx.table_name,
+ &alter_ctx.new_db,
+ &alter_ctx.new_alias))
+ DBUG_RETURN(true);
+
  /*
  Look if we have to do anything at all.
  ALTER can become NOOP after handling
@@ -9549,6 +9563,7 @@ do_continue:;
  }
  res= simple_rename_or_index_change(thd, table_list,
  alter_info->keys_onoff,
+ &trigger_param,
  &alter_ctx);
  }
  else
@@ -9805,7 +9820,7 @@ do_continue:;
  &altered_table))
  goto err_new_table_cleanup;
  /*
- Avoid creating frm again in ha_create_table() if inline alter will not
+ Avoid creating frm again in ha_create_table() if inplace alter will not
  be used.
  */
  frm_is_created= 1;
@@ -9879,9 +9894,12 @@ do_continue:;
  */
  enum_check_fields org_count_cuted_fields= thd->count_cuted_fields;
  thd->count_cuted_fields= CHECK_FIELD_WARN;
- int res= mysql_inplace_alter_table(thd, table_list, table, &altered_table,
+ int res= mysql_inplace_alter_table(thd,
+ table_list, table, &altered_table,
  &ha_alter_info,
- &target_mdl_request, &alter_ctx);
+ &target_mdl_request,
+ &trigger_param,
+ &alter_ctx);
  thd->count_cuted_fields= org_count_cuted_fields;
  my_free(const_cast<uchar*>(frm.str));
 
@@ -10216,7 +10234,7 @@ do_continue:;
  // Check if we renamed the table and if so update trigger files.
  if (alter_ctx.is_table_renamed())
  {
- if (Table_triggers_list::change_table_name(thd,
+ if (Table_triggers_list::change_table_name(thd, &trigger_param,
  &alter_ctx.db,
  &alter_ctx.alias,
  &alter_ctx.table_name,