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

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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
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6
sql/mysqld.h
View File

@@ -234,8 +234,8 @@ extern PSI_mutex_key key_BINLOG_LOCK_index, key_BINLOG_LOCK_prep_xids,
key_LOCK_connection_count, key_LOCK_crypt, key_LOCK_delayed_create,
key_LOCK_delayed_insert, key_LOCK_delayed_status, key_LOCK_error_log,
key_LOCK_gdl, key_LOCK_global_read_lock, key_LOCK_global_system_variables,
key_LOCK_lock_db, key_LOCK_logger, key_LOCK_manager, key_LOCK_mapped_file,
key_LOCK_mysql_create_db, key_LOCK_open, key_LOCK_prepared_stmt_count,
key_LOCK_logger, key_LOCK_manager, key_LOCK_mapped_file,
key_LOCK_open, key_LOCK_prepared_stmt_count,
key_LOCK_rpl_status, key_LOCK_server_started, key_LOCK_status,
key_LOCK_table_share, key_LOCK_thd_data,
key_LOCK_user_conn, key_LOCK_uuid_generator, key_LOG_LOCK_log,
@@ -323,7 +323,7 @@ extern MYSQL_PLUGIN_IMPORT key_map key_map_full; /* Should be threaded
/*
Server mutex locks and condition variables.
*/
extern mysql_mutex_t LOCK_mysql_create_db, LOCK_open, LOCK_lock_db,
extern mysql_mutex_t LOCK_open,
LOCK_mapped_file, LOCK_user_locks, LOCK_status,
LOCK_error_log, LOCK_delayed_insert, LOCK_uuid_generator,
LOCK_delayed_status, LOCK_delayed_create, LOCK_crypt, LOCK_timezone,