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mysql-5.5.18 merge

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This commit is contained in:
Sergei Golubchik
2011-11-03 19:17:05 +01:00
parent 3794110f02 6814762551
commit 0e007344ea
1160 changed files with 12821 additions and 6204 deletions
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33
sql/sql_show.cc
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@ -3573,6 +3573,10 @@ end:
*/
thd->temporary_tables= NULL;
close_thread_tables(thd);
/*
Release metadata lock we might have acquired.
See comment in fill_schema_table_from_frm() for details.
*/
thd->mdl_context.rollback_to_savepoint(open_tables_state_backup->mdl_system_tables_svp);
thd->lex= old_lex;
@ -3755,6 +3759,9 @@ try_acquire_high_prio_shared_mdl_lock(THD *thd, TABLE_LIST *table,
@param[in] db_name database name
@param[in] table_name table name
@param[in] schema_table_idx I_S table index
@param[in] open_tables_state_backup Open_tables_state object which is used
to save/restore original state of metadata
locks.
@param[in] can_deadlock Indicates that deadlocks are possible
due to metadata locks, so to avoid
them we should not wait in case if
@ -3772,6 +3779,7 @@ static int fill_schema_table_from_frm(THD *thd, TABLE_LIST *tables,
LEX_STRING *db_name,
LEX_STRING *table_name,
enum enum_schema_tables schema_table_idx,
Open_tables_backup *open_tables_state_backup,
bool can_deadlock)
{
TABLE *table= tables->table;
@ -3916,13 +3924,27 @@ end_share:
end_unlock:
mysql_mutex_unlock(&LOCK_open);
/*
Don't release the MDL lock, it can be part of a transaction.
If it is not, it will be released by the call to
MDL_context::rollback_to_savepoint() in the caller.
*/
end:
/*
Release metadata lock we might have acquired.
Without this step metadata locks acquired for each table processed
will be accumulated. In situation when a lot of tables are processed
by I_S query this will result in transaction with too many metadata
locks. As result performance of acquisition of new lock will suffer.
Of course, the fact that we don't hold metadata lock on tables which
were processed till the end of I_S query makes execution less isolated
from concurrent DDL. Consequently one might get 'dirty' results from
such a query. But we have never promised serializability of I_S queries
anyway.
We don't have any tables open since we took backup, so rolling back to
savepoint is safe.
*/
DBUG_ASSERT(thd->open_tables == NULL);
thd->mdl_context.rollback_to_savepoint(open_tables_state_backup->mdl_system_tables_svp);
thd->clear_error();
return res;
}
@ -4173,6 +4195,7 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
int res= fill_schema_table_from_frm(thd, tables, schema_table,
db_name, table_name,
schema_table_idx,
&open_tables_state_backup,
can_deadlock);
thd->pop_internal_handler();