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Moving a change_list related methods from THD to Item_change_list

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1. Moving the following methods from THD to Item_change_list:
   nocheck_register_item_tree_change()
   check_and_register_item_tree_change()
   rollback_item_tree_changes()
   as they work only with the "change_list" member and don't
   require anything else from THD.
2. Deriving THD from Item_change_list

This change will help to fix "MDEV-14603 signal 11 with short stacktrace" easier.
This commit is contained in:
Alexander Barkov 2018-01-16 16:09:51 +04:00
parent be85c2dc88
commit 81378b3947
5 changed files with 41 additions and 28 deletions
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8
sql/sp_head.cc
View File

@ -1249,7 +1249,7 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
We should also save Item tree change list to avoid rollback something
too early in the calling query.
*/
thd->change_list.move_elements_to(&old_change_list);
thd->Item_change_list::move_elements_to(&old_change_list);
/*
Cursors will use thd->packet, so they may corrupt data which was prepared
for sending by upper level. OTOH cursors in the same routine can share this
@ -1389,8 +1389,8 @@ sp_head::execute(THD *thd, bool merge_da_on_success)
/* Restore all saved */
thd->server_status= (thd->server_status & ~status_backup_mask) | old_server_status;
old_packet.swap(thd->packet);
DBUG_ASSERT(thd->change_list.is_empty());
old_change_list.move_elements_to(&thd->change_list);
DBUG_ASSERT(thd->Item_change_list::is_empty());
old_change_list.move_elements_to(thd);
thd->lex= old_lex;
thd->set_query_id(old_query_id);
DBUG_ASSERT(!thd->derived_tables);
@ -2976,7 +2976,7 @@ sp_lex_keeper::reset_lex_and_exec_core(THD *thd, uint *nextp,
bool parent_modified_non_trans_table= thd->transaction.stmt.modified_non_trans_table;
thd->transaction.stmt.modified_non_trans_table= FALSE;
DBUG_ASSERT(!thd->derived_tables);
DBUG_ASSERT(thd->change_list.is_empty());
DBUG_ASSERT(thd->Item_change_list::is_empty());
/*
Use our own lex.
We should not save old value since it is saved/restored in

10
sql/sql_class.cc
View File

@ -2605,7 +2605,9 @@ struct Item_change_record: public ilink
thd->mem_root (due to possible set_n_backup_active_arena called for thd).
*/
void THD::nocheck_register_item_tree_change(Item **place, Item *old_value,
void
Item_change_list::nocheck_register_item_tree_change(Item **place,
Item *old_value,
MEM_ROOT *runtime_memroot)
{
Item_change_record *change;
@ -2647,7 +2649,9 @@ void THD::nocheck_register_item_tree_change(Item **place, Item *old_value,
changes to substitute the same reference at both locations L1 and L2.
*/
void THD::check_and_register_item_tree_change(Item **place, Item **new_value,
void
Item_change_list::check_and_register_item_tree_change(Item **place,
Item **new_value,
MEM_ROOT *runtime_memroot)
{
Item_change_record *change;
@ -2663,7 +2667,7 @@ void THD::check_and_register_item_tree_change(Item **place, Item **new_value,
}
void THD::rollback_item_tree_changes()
void Item_change_list::rollback_item_tree_changes()
{
I_List_iterator<Item_change_record> it(change_list);
Item_change_record *change;

37
sql/sql_class.h
View File

@ -1279,7 +1279,21 @@ public:
*/
struct Item_change_record;
typedef I_List<Item_change_record> Item_change_list;
class Item_change_list
{
I_List<Item_change_record> change_list;
public:
void nocheck_register_item_tree_change(Item **place, Item *old_value,
MEM_ROOT *runtime_memroot);
void check_and_register_item_tree_change(Item **place, Item **new_value,
MEM_ROOT *runtime_memroot);
void rollback_item_tree_changes();
void move_elements_to(Item_change_list *to)
{
change_list.move_elements_to(&to->change_list);
}
bool is_empty() { return change_list.is_empty(); }
};
/**
@ -2040,6 +2054,14 @@ void dbug_serve_apcs(THD *thd, int n_calls);
*/
class THD :public Statement,
/*
This is to track items changed during execution of a prepared
statement/stored procedure. It's created by
nocheck_register_item_tree_change() in memory root of THD,
and freed in rollback_item_tree_changes().
For conventional execution it's always empty.
*/
public Item_change_list,
public MDL_context_owner,
public Open_tables_state
{
@ -2510,14 +2532,6 @@ public:
#ifdef SIGNAL_WITH_VIO_CLOSE
Vio* active_vio;
#endif
/*
This is to track items changed during execution of a prepared
statement/stored procedure. It's created by
nocheck_register_item_tree_change() in memory root of THD, and freed in
rollback_item_tree_changes(). For conventional execution it's always
empty.
*/
Item_change_list change_list;
/*
A permanent memory area of the statement. For conventional
@ -3599,11 +3613,6 @@ public:
*/
memcpy((char*) place, new_value, sizeof(*new_value));
}
void nocheck_register_item_tree_change(Item **place, Item *old_value,
MEM_ROOT *runtime_memroot);
void check_and_register_item_tree_change(Item **place, Item **new_value,
MEM_ROOT *runtime_memroot);
void rollback_item_tree_changes();
/*
Cleanup statement parse state (parse tree, lex) and execution

2
sql/sql_parse.cc
View File

@ -7910,7 +7910,7 @@ void mysql_parse(THD *thd, char *rawbuf, uint length,
sp_cache_enforce_limit(thd->sp_func_cache, stored_program_cache_size);
thd->end_statement();
thd->cleanup_after_query();
DBUG_ASSERT(thd->change_list.is_empty());
DBUG_ASSERT(thd->Item_change_list::is_empty());
}
else
{

8
sql/sql_prepare.cc
View File

@ -3930,7 +3930,7 @@ bool Prepared_statement::prepare(const char *packet, uint packet_len)
If called from a stored procedure, ensure that we won't rollback
external changes when cleaning up after validation.
*/
DBUG_ASSERT(thd->change_list.is_empty());
DBUG_ASSERT(thd->Item_change_list::is_empty());
/*
Marker used to release metadata locks acquired while the prepared
@ -4407,7 +4407,7 @@ Prepared_statement::execute_server_runnable(Server_runnable *server_runnable)
bool error;
Query_arena *save_stmt_arena= thd->stmt_arena;
Item_change_list save_change_list;
thd->change_list.move_elements_to(&save_change_list);
thd->Item_change_list::move_elements_to(&save_change_list);
state= STMT_CONVENTIONAL_EXECUTION;
@ -4426,7 +4426,7 @@ Prepared_statement::execute_server_runnable(Server_runnable *server_runnable)
thd->restore_backup_statement(this, &stmt_backup);
thd->stmt_arena= save_stmt_arena;
save_change_list.move_elements_to(&thd->change_list);
save_change_list.move_elements_to(thd);
/* Items and memory will freed in destructor */
@ -4654,7 +4654,7 @@ bool Prepared_statement::execute(String *expanded_query, bool open_cursor)
If the free_list is not empty, we'll wrongly free some externally
allocated items when cleaning up after execution of this statement.
*/
DBUG_ASSERT(thd->change_list.is_empty());
DBUG_ASSERT(thd->Item_change_list::is_empty());
/*
The only case where we should have items in the thd->free_list is