database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

MDEV-14410 - Assertion `table->pos_in_locked_tables == __null ||

Browse Source 
table->pos_in_locked_tables->table == table'
             failed in mark_used_tables_as_free_for_reuse

Assertion failure can be triggered by some DDL executed under LOCK TABLES
that holds lock for DDL target table multiple times (either explicitly or
implcitly).

When closing all table instances for given table (e.g. when preparing for
table removal during CREATE OR REPLACE), only one instance was removed
from m_locked_tables list.

Later we attempt to re-insert one of the instances in mysql_create_table()/
add_back_last_deleted_lock(), which wasn't actually removed. This leads
to m_locks_tables corruption, specifically loss of all following elements.

Then UNLOCK TABLE won't reset some table instances properly (specifically
pos_in_locked_tables), since they're not present in m_locked_tables.

Eventually such table instance gets released to table cache and then
re-used by subsequent statement, which triggers this assertion failure.
This commit is contained in:
Sergey Vojtovich
2018-09-07 14:50:10 +04:00
parent b7944343dd
commit 327b271721
4 changed files with 39 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
sql/sql_base.cc
View File

@ -806,6 +806,7 @@ close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
uint key_length= share->table_cache_key.length;
const char *db= key;
const char *table_name= db + share->db.length + 1;
bool remove_from_locked_tables= extra != HA_EXTRA_NOT_USED;
memcpy(key, share->table_cache_key.str, key_length);
@ -819,7 +820,7 @@ close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
{
thd->locked_tables_list.unlink_from_list(thd,
table->pos_in_locked_tables,
extra != HA_EXTRA_NOT_USED);
remove_from_locked_tables);
/* Inform handler that there is a drop table or a rename going on */
if (extra != HA_EXTRA_NOT_USED && table->db_stat)
{