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Pre-requisite patch for bug #51263 "Deadlock between

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transactional SELECT and ALTER TABLE ... REBUILD PARTITION".

The goal of this patch is to decouple type of metadata
lock acquired for table by open_tables() from type of
table-level lock to be acquired on it.

To achieve this we change approach to how we determine what
type of metadata lock should be acquired on table to be open.
Now instead of inferring it at open_tables() time from flags
and type of table-level lock we rely on that type of metadata
lock is properly set at parsing time and is not changed
further.
This commit is contained in:
Dmitry Lenev
2010-05-25 16:35:01 +04:00
parent 6ceacd4fb9
commit a3c080be7a
20 changed files with 359 additions and 227 deletions
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16
sql/sql_parse.cc
View File

@ -1606,7 +1606,8 @@ int prepare_schema_table(THD *thd, LEX *lex, Table_ident *table_ident,
/* 'parent_lex' is used in init_query() so it must be before it. */
schema_select_lex->parent_lex= lex;
schema_select_lex->init_query();
if (!schema_select_lex->add_table_to_list(thd, table_ident, 0, 0, TL_READ))
if (!schema_select_lex->add_table_to_list(thd, table_ident, 0, 0, TL_READ,
MDL_SHARED_READ))
DBUG_RETURN(1);
lex->query_tables_last= query_tables_last;
break;
@ -2544,7 +2545,7 @@ case SQLCOM_PREPARE:
/* Set strategies: reset default or 'prepared' values. */
create_table->open_strategy= TABLE_LIST::OPEN_IF_EXISTS;
create_table->lock_strategy= TABLE_LIST::EXCLUSIVE_DOWNGRADABLE_MDL;
create_table->lock_strategy= TABLE_LIST::OTLS_DOWNGRADE_IF_EXISTS;
/*
Close any open handlers for the table
@ -3502,16 +3503,13 @@ end_with_restore_list:
thd->global_read_lock.wait_if_global_read_lock(thd, FALSE, TRUE))
goto error;
init_mdl_requests(all_tables);
thd->variables.option_bits|= OPTION_TABLE_LOCK;
thd->in_lock_tables=1;
{
Lock_tables_prelocking_strategy lock_tables_prelocking_strategy;
res= (open_and_lock_tables(thd, all_tables, FALSE,
MYSQL_OPEN_TAKE_UPGRADABLE_MDL,
res= (open_and_lock_tables(thd, all_tables, FALSE, 0,
&lock_tables_prelocking_strategy) ||
thd->locked_tables_list.init_locked_tables(thd));
}
@ -6014,6 +6012,7 @@ bool add_to_list(THD *thd, SQL_LIST &list,Item *item,bool asc)
- TL_OPTION_FORCE_INDEX : Force usage of index
- TL_OPTION_ALIAS : an alias in multi table DELETE
@param lock_type How table should be locked
@param mdl_type Type of metadata lock to acquire on the table.
@param use_index List of indexed used in USE INDEX
@param ignore_index List of indexed used in IGNORE INDEX
@ -6028,6 +6027,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
LEX_STRING *alias,
ulong table_options,
thr_lock_type lock_type,
enum_mdl_type mdl_type,
List<Index_hint> *index_hints_arg,
LEX_STRING *option)
{
@ -6175,9 +6175,7 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
ptr->next_name_resolution_table= NULL;
/* Link table in global list (all used tables) */
lex->add_to_query_tables(ptr);
ptr->mdl_request.init(MDL_key::TABLE, ptr->db, ptr->table_name,
(ptr->lock_type >= TL_WRITE_ALLOW_WRITE) ?
MDL_SHARED_WRITE : MDL_SHARED_READ);
ptr->mdl_request.init(MDL_key::TABLE, ptr->db, ptr->table_name, mdl_type);
DBUG_RETURN(ptr);
}