1
0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00

A 5.5 version of the fix for Bug #54360 "Deadlock DROP/ALTER/CREATE

DATABASE with open HANDLER"

Remove LOCK_create_db, database name locks, and use metadata locks instead.
This exposes CREATE/DROP/ALTER DATABASE statements to the graph-based
deadlock detector in MDL, and paves the way for a safe, deadlock-free
implementation of RENAME DATABASE.

Database DDL statements will now take exclusive metadata locks on
the database name, while table/view/routine DDL statements take
intention exclusive locks on the database name. This prevents race
conditions between database DDL and table/view/routine DDL.
(e.g. DROP DATABASE with concurrent CREATE/ALTER/DROP TABLE)

By adding database name locks, this patch implements
WL#4450 "DDL locking: CREATE/DROP DATABASE must use database locks" and
WL#4985 "DDL locking: namespace/hierarchical locks".

The patch also changes code to use init_one_table() where appropriate.
The new lock_table_names() function requires TABLE_LIST::db_length to
be set correctly, and this is taken care of by init_one_table().

This patch also adds a simple template to help work with 
the mysys HASH data structure.

Most of the patch was written by Konstantin Osipov.
This commit is contained in:
Jon Olav Hauglid
2010-07-01 15:53:46 +02:00
parent 34e409fafa
commit 41a3dfe490
28 changed files with 1300 additions and 652 deletions

View File

@ -47,7 +47,7 @@ ENGINE = MYISAM
PARTITION p1 VALUES LESS THAN (20),
PARTITION p2 VALUES LESS THAN (100),
PARTITION p3 VALUES LESS THAN MAXVALUE ) */;
SET DEBUG_SYNC= 'open_tables_acquire_upgradable_mdl SIGNAL removing_partitions WAIT_FOR waiting_for_alter';
SET DEBUG_SYNC= 'alter_table_before_open_tables SIGNAL removing_partitions WAIT_FOR waiting_for_alter';
SET DEBUG_SYNC= 'alter_table_before_rename_result_table WAIT_FOR delete_done';
ALTER TABLE t2 REMOVE PARTITIONING;
# Con default