database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

Bug#30882 Dropping a temporary table inside a stored function may cause a server crash

Browse Source 
If a stored function that contains a drop temporary table statement
is invoked by a create temporary table of the same name may cause
a server crash. The problem is that when dropping a table no check
is done to ensure that table is not being used by some outer query
(or outer statement), potentially leaving the outer query with a
reference to a stale (freed) table.

The solution is when dropping a temporary table, always check if
the table is being used by some outer statement as a temporary
table can be dropped inside stored procedures.

The check is performed by looking at the TABLE::query_id value for
temporary tables. To simplify this check and to solve a bug related
to handling of temporary tables in prelocked mode, this patch changes
the way in which this member is used to track the fact that table is
used/unused. Now we ensure that TABLE::query_id is zero for unused
temporary tables (which means that all temporary tables which were
used by a statement should be marked as free for reuse after it's
execution has been completed).


mysql-test/include/handler.inc:
  Add test case for side effect of Bug#30882
mysql-test/r/handler_innodb.result:
  Add test case result for side effect of Bug#30882
mysql-test/r/handler_myisam.result:
  Add test case result for side effect of Bug#30882
mysql-test/r/sp-error.result:
  Add test case result for Bug#30882
mysql-test/t/sp-error.test:
  Add test case for Bug#30882
sql/event_db_repository.cc:
  Update close_thread_tables call, no more default values.
sql/mysql_priv.h:
  Remove implicit default parameters values of the close_thread_tables
  function as no callers are using it.
sql/slave.cc:
  Update close_thread_tables call, no more default values
sql/sp_head.cc:
  Update close_thread_tables call, no more default values
sql/sql_base.cc:
  Changed the approach to distinguishing currently unused temporary tables.
  Now we ensure that such tables always have TABLE::query_id set to 0 and
  use this fact to perform checks during opening and dropping of temporary
  tables. This means that we have to call close_thread_tables() even for
  statements which use only temporary tables. To make this call cheaper,
  we re-factored close_thread_tables() to not take LOCK_open unless there
  are open base tables.
sql/sql_handler.cc:
  Properly close temporary tables associated with a handler.
sql/sql_insert.cc:
  close_temporary_table is now merged into drop_temporary_table.
sql/sql_parse.cc:
  Now the condition doesn't cover all cases because close_thread_tables()
  must be called even for statements that use only temporary tables.
sql/sql_table.cc:
  Use drop_temporary_table which perform checks to verify if
  the table is not being used. Error path problem is due to
  a handler tables issue and is going to be addressed in bug
  31397.
sql/table.h:
  Rename previously unused clear_query_id and document the usage of
  query_id and open_by_handler.
This commit is contained in:
unknown
2007-11-01 18:52:56 -02:00
parent ecef837931
commit 611dbd0bb3
15 changed files with 431 additions and 83 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
sql/sql_parse.cc
View File

@ -992,9 +992,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
/*
Multiple queries exits, execute them individually
*/
if (thd->lock || thd->open_tables || thd->derived_tables ||
thd->prelocked_mode)
close_thread_tables(thd);
close_thread_tables(thd);
ulong length= (ulong)(packet_end - next_packet);
log_slow_statement(thd);
@ -1331,12 +1329,11 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
my_message(ER_UNKNOWN_COM_ERROR, ER(ER_UNKNOWN_COM_ERROR), MYF(0));
break;
}
if (thd->lock || thd->open_tables || thd->derived_tables ||
thd->prelocked_mode)
{
thd->proc_info="closing tables";
close_thread_tables(thd); /* Free tables */
}
thd->proc_info= "closing tables";
/* Free tables */
close_thread_tables(thd);
/*
assume handlers auto-commit (if some doesn't - transaction handling
in MySQL should be redesigned to support it; it's a big change,