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MDEV-14959: Fixed possible memory leaks that could happen on running PS/SP depending on a trigger

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Moved call of the function check_and_update_table_version() just
before the place where the function extend_table_list() is invoked
in order to avoid allocation of memory on a PS/SP memory root
marked as read only. It happens by the reason that the function
extend_table_list() invokes sp_add_used_routine() to add a trigger
created for the table in time frame between execution the statement
EXECUTE `stmt_id` .

For example, the following test case
create table t1 (a int);

prepare stmt from "insert into t1 (a) value (1)";
execute stmt;

create trigger t1_bi before insert on t1 for each row
  set @message= new.a;

execute stmt; # (*)

adds the trigger t1_bi to a list of used routines that involves
allocation of a memory on PS memory root that has been already marked
as read only on first run of the statement 'execute stmt'.
In result, when the statement marked with (*) is executed it results in
assert hit.

To fix the issue call the function check_and_update_table_version()
before invocation of extend_table_list() to force re-compilation of
PS/SP that resets read-only flag of its memory root.
This commit is contained in:
Dmitry Shulga 2023-09-01 19:27:01 +07:00
parent d8574dbba3
commit 1d502a29e5
1 changed files with 6 additions and 5 deletions
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11
sql/sql_base.cc
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@ -3965,6 +3965,12 @@ open_and_process_table(THD *thd, TABLE_LIST *tables, uint *counter, uint flags,
if (tables->open_strategy && !tables->table)
goto end;
/* Check and update metadata version of a base table. */
error= check_and_update_table_version(thd, tables, tables->table->s);
if (unlikely(error))
goto end;
error= extend_table_list(thd, tables, prelocking_strategy, has_prelocking_list);
if (unlikely(error))
goto end;
@ -3972,11 +3978,6 @@ open_and_process_table(THD *thd, TABLE_LIST *tables, uint *counter, uint flags,
/* Copy grant information from TABLE_LIST instance to TABLE one. */
tables->table->grant= tables->grant;
/* Check and update metadata version of a base table. */
error= check_and_update_table_version(thd, tables, tables->table->s);
if (unlikely(error))
goto end;
/*
After opening a MERGE table add the children to the query list of
tables, so that they are opened too.