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Bug#21074 Large query_cache freezes mysql server sporadically under heavy load

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Invaldating a subset of a sufficiently large query cache can take a long time.
During this time the server is efficiently frozen and no other operation can
be executed. This patch addresses this problem by moving the locks which cause
the freezing and also by temporarily disable the query cache while the 
invalidation takes place.
This commit is contained in:
thek@adventure.(none)
2007-07-02 19:14:48 +02:00
parent 6044940b25
commit 863e882785
10 changed files with 677 additions and 372 deletions
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40
sql/sql_trigger.cc
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@@ -1268,8 +1268,6 @@ bool Table_triggers_list::drop_all_triggers(THD *thd, char *db, char *name)
bzero(&table, sizeof(table));
init_alloc_root(&table.mem_root, 8192, 0);
safe_mutex_assert_owner(&LOCK_open);
if (Table_triggers_list::check_n_load(thd, db, name, &table, 1))
{
result= 1;
@@ -1431,26 +1429,24 @@ Table_triggers_list::change_table_name_in_trignames(const char *db_name,
}
/*
Update .TRG and .TRN files after renaming triggers' subject table.
/**
@brief Update .TRG and .TRN files after renaming triggers' subject table.
SYNOPSIS
change_table_name()
thd Thread context
db Old database of subject table
old_table Old name of subject table
new_db New database for subject table
new_table New name of subject table
@param[in,out] thd Thread context
@param[in] db Old database of subject table
@param[in] old_table Old name of subject table
@param[in] new_db New database for subject table
@param[in] new_table New name of subject table
NOTE
@note
This method tries to leave trigger related files in consistent state,
i.e. it either will complete successfully, or will fail leaving files
in their initial state.
Also this method assumes that subject table is not renamed to itself.
This method needs to be called under an exclusive table name lock.
RETURN VALUE
FALSE Success
TRUE Error
@retval FALSE Success
@retval TRUE Error
*/
bool Table_triggers_list::change_table_name(THD *thd, const char *db,
@@ -1466,7 +1462,19 @@ bool Table_triggers_list::change_table_name(THD *thd, const char *db,
bzero(&table, sizeof(table));
init_alloc_root(&table.mem_root, 8192, 0);
safe_mutex_assert_owner(&LOCK_open);
uchar key[MAX_DBKEY_LENGTH];
uint key_length= (uint) (strmov(strmov((char*)&key[0], db)+1,
old_table)-(char*)&key[0])+1;
/*
This method interfaces the mysql server code protected by
either LOCK_open mutex or with an exclusive table name lock.
In the future, only an exclusive table name lock will be enough.
*/
#ifndef DBUG_OFF
if (!is_table_name_exclusively_locked_by_this_thread(thd, key, key_length))
safe_mutex_assert_owner(&LOCK_open);
#endif
DBUG_ASSERT(my_strcasecmp(table_alias_charset, db, new_db) ||
my_strcasecmp(table_alias_charset, old_table, new_table));