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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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82
sql/sql_table.cc
View File

@@ -1411,14 +1411,7 @@ bool mysql_rm_table(THD *thd,TABLE_LIST *tables, my_bool if_exists,
LOCK_open during wait_if_global_read_lock(), other threads could not
close their tables. This would make a pretty deadlock.
*/
thd->mysys_var->current_mutex= &LOCK_open;
thd->mysys_var->current_cond= &COND_refresh;
VOID(pthread_mutex_lock(&LOCK_open));
error= mysql_rm_table_part2(thd, tables, if_exists, drop_temporary, 0, 0);
pthread_mutex_unlock(&LOCK_open);
error= mysql_rm_table_part2(thd, tables, if_exists, drop_temporary, 0, 0, 1);
pthread_mutex_lock(&thd->mysys_var->mutex);
thd->mysys_var->current_mutex= 0;
thd->mysys_var->current_cond= 0;
@@ -1433,49 +1426,6 @@ bool mysql_rm_table(THD *thd,TABLE_LIST *tables, my_bool if_exists,
DBUG_RETURN(FALSE);
}
/*
delete (drop) tables.
SYNOPSIS
mysql_rm_table_part2_with_lock()
thd Thread handle
tables List of tables to delete
if_exists If 1, don't give error if one table doesn't exists
dont_log_query Don't write query to log files. This will also not
generate warnings if the handler files doesn't exists
NOTES
Works like documented in mysql_rm_table(), but don't check
global_read_lock and don't send_ok packet to server.
RETURN
0 ok
1 error
*/
int mysql_rm_table_part2_with_lock(THD *thd,
TABLE_LIST *tables, bool if_exists,
bool drop_temporary, bool dont_log_query)
{
int error;
thd->mysys_var->current_mutex= &LOCK_open;
thd->mysys_var->current_cond= &COND_refresh;
VOID(pthread_mutex_lock(&LOCK_open));
error= mysql_rm_table_part2(thd, tables, if_exists, drop_temporary, 1,
dont_log_query);
pthread_mutex_unlock(&LOCK_open);
pthread_mutex_lock(&thd->mysys_var->mutex);
thd->mysys_var->current_mutex= 0;
thd->mysys_var->current_cond= 0;
pthread_mutex_unlock(&thd->mysys_var->mutex);
return error;
}
/*
Execute the drop of a normal or temporary table
@@ -1508,7 +1458,7 @@ int mysql_rm_table_part2_with_lock(THD *thd,
int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
bool drop_temporary, bool drop_view,
bool dont_log_query)
bool dont_log_query, bool need_lock_open)
{
TABLE_LIST *table;
char path[FN_REFLEN], *alias;
@@ -1520,9 +1470,11 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
String built_query;
DBUG_ENTER("mysql_rm_table_part2");
if (need_lock_open)
pthread_mutex_lock(&LOCK_open);
LINT_INIT(alias);
LINT_INIT(path_length);
safe_mutex_assert_owner(&LOCK_open);
if (thd->current_stmt_binlog_row_based && !dont_log_query)
{
@@ -1555,8 +1507,15 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
}
}
if (!drop_temporary && lock_table_names(thd, tables))
if (!drop_temporary && lock_table_names_exclusively(thd, tables))
{
if (need_lock_open)
pthread_mutex_unlock(&LOCK_open);
DBUG_RETURN(1);
}
if (need_lock_open)
pthread_mutex_unlock(&LOCK_open);
/* Don't give warnings for not found errors, as we already generate notes */
thd->no_warnings_for_error= 1;
@@ -1567,7 +1526,7 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
handlerton *table_type;
enum legacy_db_type frm_db_type;
mysql_ha_flush(thd, table, MYSQL_HA_CLOSE_FINAL, TRUE);
mysql_ha_flush(thd, table, MYSQL_HA_CLOSE_FINAL, !need_lock_open);
if (!close_temporary_table(thd, table))
{
tmp_table_deleted=1;
@@ -1604,6 +1563,8 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
{
TABLE *locked_table;
abort_locked_tables(thd, db, table->table_name);
if (need_lock_open)
pthread_mutex_lock(&LOCK_open);
remove_table_from_cache(thd, db, table->table_name,
RTFC_WAIT_OTHER_THREAD_FLAG |
RTFC_CHECK_KILLED_FLAG);
@@ -1614,6 +1575,9 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
if ((locked_table= drop_locked_tables(thd, db, table->table_name)))
table->table= locked_table;
if (need_lock_open)
pthread_mutex_unlock(&LOCK_open);
if (thd->killed)
{
thd->no_warnings_for_error= 0;
@@ -1739,9 +1703,11 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
*/
}
}
if (!drop_temporary)
unlock_table_names(thd, tables, (TABLE_LIST*) 0);
if (need_lock_open)
pthread_mutex_lock(&LOCK_open);
unlock_table_names(thd, tables, (TABLE_LIST*) 0);
if (need_lock_open)
pthread_mutex_unlock(&LOCK_open);
thd->no_warnings_for_error= 0;
DBUG_RETURN(error);
}