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

Fix for bug #50908 "Assertion `handler_tables_hash.records == 0'

Browse Source 
failed in enter_locked_tables_mode".

Server was aborted due to assertion failure when one tried to 
execute statement requiring prelocking (i.e. firing triggers
or using stored functions) while having open HANDLERs.

The problem was that THD::enter_locked_tables_mode() method
which was called at the beginning of execution of prelocked 
statement assumed there are no open HANDLERs. It had to do 
so because corresponding THD::leave_locked_tables_mode()
method was unable to properly restore MDL sentinel when
leaving LOCK TABLES/prelocked mode in the presence of open 
HANDLERs.

This patch solves this problem by changing the latter method
to properly restore MDL sentinel and thus removing need for 
this assumption. As a side-effect, it lifts unjustified
limitation by allowing to keep HANDLERs open when entering 
LOCK TABLES mode.
This commit is contained in:
Dmitry Lenev
2010-02-12 10:05:43 +03:00
parent bca1fec83e
commit 0ec868ca0e
8 changed files with 580 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
sql/sql_handler.cc
View File

@ -837,3 +837,27 @@ void mysql_ha_cleanup(THD *thd)
DBUG_VOID_RETURN;
}
/**
Move tickets for metadata locks corresponding to open HANDLERs
after transaction sentinel in order to protect them from being
released at the end of transaction.
@param thd Thread identifier.
*/
void mysql_ha_move_tickets_after_trans_sentinel(THD *thd)
{
TABLE_LIST *hash_tables;
DBUG_ENTER("mysql_ha_move_tickets_after_trans_sentinel");
for (uint i= 0; i < thd->handler_tables_hash.records; i++)
{
hash_tables= (TABLE_LIST*) my_hash_element(&thd->handler_tables_hash, i);
if (hash_tables->table && hash_tables->table->mdl_ticket)
thd->mdl_context.
move_ticket_after_trans_sentinel(hash_tables->table->mdl_ticket);
}
DBUG_VOID_RETURN;
}