diff options
| -rw-r--r-- | mysql-test/r/ps.result | 128 | ||||
| -rw-r--r-- | mysql-test/t/ps.test | 141 | ||||
| -rw-r--r-- | sql/item_row.cc | 16 | ||||
| -rw-r--r-- | sql/item_row.h | 3 | ||||
| -rw-r--r-- | sql/mysql_priv.h | 4 | ||||
| -rw-r--r-- | sql/mysqld.cc | 33 | ||||
| -rw-r--r-- | sql/set_var.cc | 42 | ||||
| -rw-r--r-- | sql/set_var.h | 59 | ||||
| -rw-r--r-- | sql/sql_class.cc | 119 | ||||
| -rw-r--r-- | sql/sql_class.h | 28 | ||||
| -rw-r--r-- | sql/sql_prepare.cc | 8 |
11 files changed, 518 insertions, 63 deletions
diff --git a/mysql-test/r/ps.result b/mysql-test/r/ps.result index e94c2952893..2be5366b180 100644 --- a/mysql-test/r/ps.result +++ b/mysql-test/r/ps.result @@ -107,6 +107,9 @@ set @fvar= 123.4567; prepare stmt1 from @fvar; ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '123.4567' at line 1 drop table t1,t2; +deallocate prepare stmt3; +deallocate prepare stmt4; +deallocate prepare stmt5; PREPARE stmt1 FROM "select _utf8 'A' collate utf8_bin = ?"; set @var='A'; EXECUTE stmt1 USING @var; @@ -252,6 +255,7 @@ set names latin1; execute `ü`; 1234 1234 +deallocate prepare `ü`; set names default; create table t1 (a varchar(10)) charset=utf8; insert into t1 (a) values ('yahoo'); @@ -747,3 +751,127 @@ length(a) 10 drop table t1; deallocate prepare stmt; +create table t1 (col1 integer, col2 integer); +insert into t1 values(100,100),(101,101),(102,102),(103,103); +prepare stmt from 'select col1, col2 from t1 where (col1, col2) in ((?,?))'; +set @a=100, @b=100; +execute stmt using @a,@b; +col1 col2 +100 100 +set @a=101, @b=101; +execute stmt using @a,@b; +col1 col2 +101 101 +set @a=102, @b=102; +execute stmt using @a,@b; +col1 col2 +102 102 +set @a=102, @b=103; +execute stmt using @a,@b; +col1 col2 +deallocate prepare stmt; +drop table t1; +set @old_max_prepared_stmt_count= @@max_prepared_stmt_count; +show variables like 'max_prepared_stmt_count'; +Variable_name Value +max_prepared_stmt_count 16382 +show variables like 'prepared_stmt_count'; +Variable_name Value +prepared_stmt_count 0 +select @@max_prepared_stmt_count, @@prepared_stmt_count; +@@max_prepared_stmt_count @@prepared_stmt_count +16382 0 +set global max_prepared_stmt_count=-1; +select @@max_prepared_stmt_count; +@@max_prepared_stmt_count +0 +set global max_prepared_stmt_count=10000000000000000; +select @@max_prepared_stmt_count; +@@max_prepared_stmt_count +1048576 +set global max_prepared_stmt_count=default; +select @@max_prepared_stmt_count; +@@max_prepared_stmt_count +16382 +set @@max_prepared_stmt_count=1; +ERROR HY000: Variable 'max_prepared_stmt_count' is a GLOBAL variable and should be set with SET GLOBAL +set max_prepared_stmt_count=1; +ERROR HY000: Variable 'max_prepared_stmt_count' is a GLOBAL variable and should be set with SET GLOBAL +set local max_prepared_stmt_count=1; +ERROR HY000: Variable 'max_prepared_stmt_count' is a GLOBAL variable and should be set with SET GLOBAL +set local prepared_stmt_count=0; +ERROR HY000: Variable 'prepared_stmt_count' is a GLOBAL variable and should be set with SET GLOBAL +set @@prepared_stmt_count=0; +ERROR HY000: Variable 'prepared_stmt_count' is a GLOBAL variable and should be set with SET GLOBAL +set global prepared_stmt_count=1; +ERROR 42000: Incorrect argument type to variable 'prepared_stmt_count' +set global max_prepared_stmt_count=1; +select @@max_prepared_stmt_count; +@@max_prepared_stmt_count +1 +set global max_prepared_stmt_count=0; +select @@max_prepared_stmt_count, @@prepared_stmt_count; +@@max_prepared_stmt_count @@prepared_stmt_count +0 0 +prepare stmt from "select 1"; +ERROR HY000: Unknown error +select @@prepared_stmt_count; +@@prepared_stmt_count +0 +set global max_prepared_stmt_count=1; +prepare stmt from "select 1"; +select @@prepared_stmt_count; +@@prepared_stmt_count +1 +prepare stmt1 from "select 1"; +ERROR HY000: Unknown error +select @@prepared_stmt_count; +@@prepared_stmt_count +1 +deallocate prepare stmt; +select @@prepared_stmt_count; +@@prepared_stmt_count +0 +prepare stmt from "select 1"; +select @@prepared_stmt_count; +@@prepared_stmt_count +1 +prepare stmt from "select 2"; +select @@prepared_stmt_count; +@@prepared_stmt_count +1 +select @@prepared_stmt_count, @@max_prepared_stmt_count; +@@prepared_stmt_count @@max_prepared_stmt_count +1 1 +set global max_prepared_stmt_count=0; +prepare stmt from "select 1"; +ERROR HY000: Unknown error +execute stmt; +ERROR HY000: Unknown prepared statement handler (stmt) given to EXECUTE +select @@prepared_stmt_count; +@@prepared_stmt_count +0 +prepare stmt from "select 1"; +ERROR HY000: Unknown error +select @@prepared_stmt_count; +@@prepared_stmt_count +0 +set global max_prepared_stmt_count=3; +select @@max_prepared_stmt_count, @@prepared_stmt_count; +@@max_prepared_stmt_count @@prepared_stmt_count +3 0 +prepare stmt from "select 1"; +prepare stmt from "select 2"; +prepare stmt1 from "select 3"; +prepare stmt2 from "select 4"; +ERROR HY000: Unknown error +prepare stmt2 from "select 4"; +ERROR HY000: Unknown error +select @@max_prepared_stmt_count, @@prepared_stmt_count; +@@max_prepared_stmt_count @@prepared_stmt_count +3 3 +deallocate prepare stmt; +select @@max_prepared_stmt_count, @@prepared_stmt_count; +@@max_prepared_stmt_count @@prepared_stmt_count +3 0 +set global max_prepared_stmt_count= @old_max_prepared_stmt_count; diff --git a/mysql-test/t/ps.test b/mysql-test/t/ps.test index af885a5c02f..d6dcf02d5b7 100644 --- a/mysql-test/t/ps.test +++ b/mysql-test/t/ps.test @@ -111,6 +111,9 @@ set @fvar= 123.4567; prepare stmt1 from @fvar; drop table t1,t2; +deallocate prepare stmt3; +deallocate prepare stmt4; +deallocate prepare stmt5; # # Bug #4105: Server crash on attempt to prepare a statement with character @@ -254,6 +257,7 @@ prepare `ü` from 'select 1234'; execute `ü` ; set names latin1; execute `ü`; +deallocate prepare `ü`; set names default; @@ -785,4 +789,141 @@ select length(a) from t1; drop table t1; deallocate prepare stmt; +# +# Bug#16248 "WHERE (col1,col2) IN ((?,?)) gives wrong results": +# check that ROW implementation is reexecution-friendly. +# +create table t1 (col1 integer, col2 integer); +insert into t1 values(100,100),(101,101),(102,102),(103,103); +prepare stmt from 'select col1, col2 from t1 where (col1, col2) in ((?,?))'; +set @a=100, @b=100; +execute stmt using @a,@b; +set @a=101, @b=101; +execute stmt using @a,@b; +set @a=102, @b=102; +execute stmt using @a,@b; +set @a=102, @b=103; +execute stmt using @a,@b; +deallocate prepare stmt; +drop table t1; + +# +# Bug#16365 Prepared Statements: DoS with too many open statements +# Check that the limit @@max_prpeared_stmt_count works. +# +# Save the old value +set @old_max_prepared_stmt_count= @@max_prepared_stmt_count; +# +# Disable prepared statement protocol: in this test we set +# @@max_prepared_stmt_count to 0 or 1 and would like to test the limit +# manually. +# +--disable_ps_protocol +# +# A. Check that the new variables are present in SHOW VARIABLES list. +# +show variables like 'max_prepared_stmt_count'; +show variables like 'prepared_stmt_count'; +# +# B. Check that the new variables are selectable. +# +select @@max_prepared_stmt_count, @@prepared_stmt_count; +# +# C. Check that max_prepared_stmt_count is settable (global only), +# whereas prepared_stmt_count is readonly. +# +set global max_prepared_stmt_count=-1; +select @@max_prepared_stmt_count; +set global max_prepared_stmt_count=10000000000000000; +select @@max_prepared_stmt_count; +set global max_prepared_stmt_count=default; +select @@max_prepared_stmt_count; +--error 1229 # ER_GLOBAL_VARIABLE +set @@max_prepared_stmt_count=1; +--error 1229 # ER_GLOBAL_VARIABLE +set max_prepared_stmt_count=1; +--error 1229 # ER_GLOBAL_VARIABLE +set local max_prepared_stmt_count=1; +--error 1229 # ER_GLOBAL_VARIABLE +set local prepared_stmt_count=0; +--error 1229 # ER_GLOBAL_VARIABLE +set @@prepared_stmt_count=0; +--error 1232 # ER_WRONG_TYPE_FOR_VAR +set global prepared_stmt_count=1; +# set to a reasonable limit works +set global max_prepared_stmt_count=1; +select @@max_prepared_stmt_count; +# +# D. Check that the variables actually work. +# +set global max_prepared_stmt_count=0; +select @@max_prepared_stmt_count, @@prepared_stmt_count; +--error 1105 # ER_UNKNOWN_ERROR +prepare stmt from "select 1"; +select @@prepared_stmt_count; +set global max_prepared_stmt_count=1; +prepare stmt from "select 1"; +select @@prepared_stmt_count; +--error 1105 # ER_UNKNOWN_ERROR +prepare stmt1 from "select 1"; +select @@prepared_stmt_count; +deallocate prepare stmt; +select @@prepared_stmt_count; +# +# E. Check that we can prepare a statement with the same name +# successfully, without hitting the limit. +# +prepare stmt from "select 1"; +select @@prepared_stmt_count; +prepare stmt from "select 2"; +select @@prepared_stmt_count; +# +# F. We can set the max below the current count. In this case no new +# statements should be allowed to prepare. +# +select @@prepared_stmt_count, @@max_prepared_stmt_count; +set global max_prepared_stmt_count=0; +--error 1105 # ER_UNKNOWN_ERROR +prepare stmt from "select 1"; +# Result: the old statement is deallocated, the new is not created. +--error 1243 # ER_UNKNOWN_STMT_HANDLER +execute stmt; +select @@prepared_stmt_count; +--error 1105 # ER_UNKNOWN_ERROR +prepare stmt from "select 1"; +select @@prepared_stmt_count; +# +# G. Show that the variables are up to date even after a connection with all +# statements in it was terminated. +# +set global max_prepared_stmt_count=3; +select @@max_prepared_stmt_count, @@prepared_stmt_count; +prepare stmt from "select 1"; +connect (con1,localhost,root,,); +connection con1; +prepare stmt from "select 2"; +prepare stmt1 from "select 3"; +--error 1105 # ER_UNKNOWN_ERROR +prepare stmt2 from "select 4"; +connection default; +--error 1105 # ER_UNKNOWN_ERROR +prepare stmt2 from "select 4"; +select @@max_prepared_stmt_count, @@prepared_stmt_count; +disconnect con1; +connection default; +# Wait for the connection to die: deal with a possible race +deallocate prepare stmt; +let $count= `select @@prepared_stmt_count`; +if ($count) +{ +--sleep 2 + let $count= `select @@prepared_stmt_count`; +} +select @@max_prepared_stmt_count, @@prepared_stmt_count; +# +# Restore the old value. +# +set global max_prepared_stmt_count= @old_max_prepared_stmt_count; +--enable_ps_protocol + # End of 4.1 tests diff --git a/sql/item_row.cc b/sql/item_row.cc index 12d202a1699..493eefc9ff0 100644 --- a/sql/item_row.cc +++ b/sql/item_row.cc @@ -26,7 +26,7 @@ */ Item_row::Item_row(List<Item> &arg): - Item(), used_tables_cache(0), array_holder(1), const_item_cache(1), with_null(0) + Item(), used_tables_cache(0), const_item_cache(1), with_null(0) { //TODO: think placing 2-3 component items in item (as it done for function) @@ -85,6 +85,20 @@ bool Item_row::fix_fields(THD *thd, TABLE_LIST *tabl, Item **ref) } +void Item_row::cleanup() +{ + DBUG_ENTER("Item_row::cleanup"); + + Item::cleanup(); + /* Reset to the original values */ + used_tables_cache= 0; + const_item_cache= 1; + with_null= 0; + + DBUG_VOID_RETURN; +} + + void Item_row::split_sum_func(THD *thd, Item **ref_pointer_array, List<Item> &fields) { diff --git a/sql/item_row.h b/sql/item_row.h index 39bc4513e1e..28cb47b6815 100644 --- a/sql/item_row.h +++ b/sql/item_row.h @@ -19,7 +19,6 @@ class Item_row: public Item Item **items; table_map used_tables_cache; uint arg_count; - bool array_holder; bool const_item_cache; bool with_null; public: @@ -29,7 +28,6 @@ public: items(item->items), used_tables_cache(item->used_tables_cache), arg_count(item->arg_count), - array_holder(0), const_item_cache(item->const_item_cache), with_null(0) {} @@ -57,6 +55,7 @@ public: return 0; }; bool fix_fields(THD *thd, TABLE_LIST *tables, Item **ref); + void cleanup(); void split_sum_func(THD *thd, Item **ref_pointer_array, List<Item> &fields); table_map used_tables() const { return used_tables_cache; }; bool const_item() const { return const_item_cache; }; diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h index 72424819078..6676d994cfa 100644 --- a/sql/mysql_priv.h +++ b/sql/mysql_priv.h @@ -918,6 +918,7 @@ extern ulong ha_commit_count, ha_rollback_count,table_cache_size; extern ulong max_connections,max_connect_errors, connect_timeout; extern ulong slave_net_timeout, slave_trans_retries; extern ulong max_user_connections; +extern ulong max_prepared_stmt_count, prepared_stmt_count; extern ulong long_query_count, what_to_log,flush_time; extern ulong query_buff_size, thread_stack,thread_stack_min; extern ulong binlog_cache_size, max_binlog_cache_size, open_files_limit; @@ -961,7 +962,8 @@ extern pthread_mutex_t LOCK_mysql_create_db,LOCK_Acl,LOCK_open, LOCK_error_log, LOCK_delayed_insert, LOCK_uuid_generator, LOCK_delayed_status, LOCK_delayed_create, LOCK_crypt, LOCK_timezone, LOCK_slave_list, LOCK_active_mi, LOCK_manager, - LOCK_global_system_variables, LOCK_user_conn; + LOCK_global_system_variables, LOCK_user_conn, + LOCK_prepared_stmt_count; #ifdef HAVE_OPENSSL extern pthread_mutex_t LOCK_des_key_file; #endif diff --git a/sql/mysqld.cc b/sql/mysqld.cc index cce48cc0d54..e68762868a4 100644 --- a/sql/mysqld.cc +++ b/sql/mysqld.cc @@ -336,6 +336,22 @@ ulong specialflag=0,opened_tables=0,created_tmp_tables=0, ulong binlog_cache_use= 0, binlog_cache_disk_use= 0; ulong max_connections,max_used_connections, max_connect_errors, max_user_connections = 0; +/* + Limit of the total number of prepared statements in the server. + Is necessary to protect the server against out-of-memory attacks. +*/ +ulong max_prepared_stmt_count; +/* + Current total number of prepared statements in the server. This number + is exact, and therefore may not be equal to the difference between + `com_stmt_prepare' and `com_stmt_close' (global status variables), as + the latter ones account for all registered attempts to prepare + a statement (including unsuccessful ones). Prepared statements are + currently connection-local: if the same SQL query text is prepared in + two different connections, this counts as two distinct prepared + statements. +*/ +ulong prepared_stmt_count=0; ulong thread_id=1L,current_pid; ulong slow_launch_threads = 0, sync_binlog_period; ulong expire_logs_days = 0; @@ -421,6 +437,14 @@ pthread_mutex_t LOCK_mysql_create_db, LOCK_Acl, LOCK_open, LOCK_thread_count, LOCK_crypt, LOCK_bytes_sent, LOCK_bytes_received, LOCK_global_system_variables, LOCK_user_conn, LOCK_slave_list, LOCK_active_mi; +/* + The below lock protects access to two global server variables: + max_prepared_stmt_count and prepared_stmt_count. These variables + set the limit and hold the current total number of prepared statements + in the server, respectively. As PREPARE/DEALLOCATE rate in a loaded + server may be fairly high, we need a dedicated lock. +*/ +pthread_mutex_t LOCK_prepared_stmt_count; #ifdef HAVE_OPENSSL pthread_mutex_t LOCK_des_key_file; #endif @@ -1118,6 +1142,7 @@ static void clean_up_mutexes() (void) rwlock_destroy(&LOCK_sys_init_connect); (void) rwlock_destroy(&LOCK_sys_init_slave); (void) pthread_mutex_destroy(&LOCK_global_system_variables); + (void) pthread_mutex_destroy(&LOCK_prepared_stmt_count); (void) pthread_cond_destroy(&COND_thread_count); (void) pthread_cond_destroy(&COND_refresh); (void) pthread_cond_destroy(&COND_thread_cache); @@ -2635,6 +2660,7 @@ static int init_thread_environment() (void) pthread_mutex_init(&LOCK_user_conn, MY_MUTEX_INIT_FAST); (void) pthread_mutex_init(&LOCK_active_mi, MY_MUTEX_INIT_FAST); (void) pthread_mutex_init(&LOCK_global_system_variables, MY_MUTEX_INIT_FAST); + (void) pthread_mutex_init(&LOCK_prepared_stmt_count, MY_MUTEX_INIT_FAST); (void) pthread_mutex_init(&LOCK_uuid_generator, MY_MUTEX_INIT_FAST); #ifdef HAVE_OPENSSL (void) pthread_mutex_init(&LOCK_des_key_file,MY_MUTEX_INIT_FAST); @@ -4238,7 +4264,8 @@ enum options_mysqld OPT_MAX_BINLOG_CACHE_SIZE, OPT_MAX_BINLOG_SIZE, OPT_MAX_CONNECTIONS, OPT_MAX_CONNECT_ERRORS, OPT_MAX_DELAYED_THREADS, OPT_MAX_HEP_TABLE_SIZE, - OPT_MAX_JOIN_SIZE, OPT_MAX_RELAY_LOG_SIZE, OPT_MAX_SORT_LENGTH, + OPT_MAX_JOIN_SIZE, OPT_MAX_PREPARED_STMT_COUNT, + OPT_MAX_RELAY_LOG_SIZE, OPT_MAX_SORT_LENGTH, OPT_MAX_SEEKS_FOR_KEY, OPT_MAX_TMP_TABLES, OPT_MAX_USER_CONNECTIONS, OPT_MAX_LENGTH_FOR_SORT_DATA, OPT_MAX_WRITE_LOCK_COUNT, OPT_BULK_INSERT_BUFFER_SIZE, @@ -5225,6 +5252,10 @@ The minimum value for this variable is 4096.", (gptr*) &global_system_variables.max_length_for_sort_data, (gptr*) &max_system_variables.max_length_for_sort_data, 0, GET_ULONG, REQUIRED_ARG, 1024, 4, 8192*1024L, 0, 1, 0}, + {"max_prepared_stmt_count", OPT_MAX_PREPARED_STMT_COUNT, + "Maximum numbrer of prepared statements in the server.", + (gptr*) &max_prepared_stmt_count, (gptr*) &max_prepared_stmt_count, + 0, GET_ULONG, REQUIRED_ARG, 16382, 0, 1*1024*1024, 0, 1, 0}, {"max_relay_log_size", OPT_MAX_RELAY_LOG_SIZE, "If non-zero: relay log will be rotated automatically when the size exceeds this value; if zero (the default): when the size exceeds max_binlog_size. 0 excepted, the minimum value for this variable is 4096.", (gptr*) &max_relay_log_size, (gptr*) &max_relay_log_size, 0, GET_ULONG, diff --git a/sql/set_var.cc b/sql/set_var.cc index e10bfda62b7..681c70c4c02 100644 --- a/sql/set_var.cc +++ b/sql/set_var.cc @@ -118,6 +118,7 @@ static KEY_CACHE *create_key_cache(const char *name, uint length); void fix_sql_mode_var(THD *thd, enum_var_type type); static byte *get_error_count(THD *thd); static byte *get_warning_count(THD *thd); +static byte *get_prepared_stmt_count(THD *thd); static byte *get_have_innodb(THD *thd); /* @@ -239,6 +240,10 @@ sys_var_thd_ha_rows sys_sql_max_join_size("sql_max_join_size", &SV::max_join_size, fix_max_join_size); #endif +static sys_var_long_ptr_global +sys_max_prepared_stmt_count("max_prepared_stmt_count", + &max_prepared_stmt_count, + &LOCK_prepared_stmt_count); sys_var_long_ptr sys_max_relay_log_size("max_relay_log_size", &max_relay_log_size, fix_max_relay_log_size); @@ -472,6 +477,9 @@ static sys_var_readonly sys_warning_count("warning_count", OPT_SESSION, SHOW_LONG, get_warning_count); +static sys_var_readonly sys_prepared_stmt_count("prepared_stmt_count", + OPT_GLOBAL, SHOW_LONG, + get_prepared_stmt_count); /* alias for last_insert_id() to be compatible with Sybase */ #ifdef HAVE_REPLICATION @@ -569,6 +577,7 @@ sys_var *sys_variables[]= &sys_max_heap_table_size, &sys_max_join_size, &sys_max_length_for_sort_data, + &sys_max_prepared_stmt_count, &sys_max_relay_log_size, &sys_max_seeks_for_key, &sys_max_sort_length, @@ -589,6 +598,7 @@ sys_var *sys_variables[]= &sys_new_mode, &sys_old_passwords, &sys_preload_buff_size, + &sys_prepared_stmt_count, &sys_pseudo_thread_id, &sys_query_alloc_block_size, &sys_query_cache_size, @@ -801,6 +811,8 @@ struct show_var_st init_vars[]= { {sys_max_join_size.name, (char*) &sys_max_join_size, SHOW_SYS}, {sys_max_length_for_sort_data.name, (char*) &sys_max_length_for_sort_data, SHOW_SYS}, + {sys_max_prepared_stmt_count.name, (char*) &sys_max_prepared_stmt_count, + SHOW_SYS}, {sys_max_relay_log_size.name, (char*) &sys_max_relay_log_size, SHOW_SYS}, {sys_max_seeks_for_key.name, (char*) &sys_max_seeks_for_key, SHOW_SYS}, {sys_max_sort_length.name, (char*) &sys_max_sort_length, SHOW_SYS}, @@ -838,6 +850,7 @@ struct show_var_st init_vars[]= { {sys_old_passwords.name, (char*) &sys_old_passwords, SHOW_SYS}, {"open_files_limit", (char*) &open_files_limit, SHOW_LONG}, {"pid_file", (char*) pidfile_name, SHOW_CHAR}, + {sys_prepared_stmt_count.name, (char*) &sys_prepared_stmt_count, SHOW_SYS}, {"port", (char*) &mysqld_port, SHOW_INT}, {sys_preload_buff_size.name, (char*) &sys_preload_buff_size, SHOW_SYS}, {"protocol_version", (char*) &protocol_version, SHOW_INT}, @@ -1251,29 +1264,40 @@ static void fix_server_id(THD *thd, enum_var_type type) server_id_supplied = 1; } -bool sys_var_long_ptr::check(THD *thd, set_var *var) + +sys_var_long_ptr:: +sys_var_long_ptr(const char *name_arg, ulong *value_ptr, + sys_after_update_func after_update_arg) + :sys_var_long_ptr_global(name_arg, value_ptr, + &LOCK_global_system_variables, after_update_arg) +{} + + +bool sys_var_long_ptr_global::check(THD *thd, set_var *var) { longlong v= var->value->val_int(); var->save_result.ulonglong_value= v < 0 ? 0 : v; return 0; } -bool sys_var_long_ptr::update(THD *thd, set_var *var) +bool sys_var_long_ptr_global::update(THD *thd, set_var *var) { ulonglong tmp= var->save_result.ulonglong_value; - pthread_mutex_lock(&LOCK_global_system_variables); + pthread_mutex_lock(guard); if (option_limits) *value= (ulong) getopt_ull_limit_value(tmp, option_limits); else *value= (ulong) tmp; - pthread_mutex_unlock(&LOCK_global_system_variables); + pthread_mutex_unlock(guard); return 0; } -void sys_var_long_ptr::set_default(THD *thd, enum_var_type type) +void sys_var_long_ptr_global::set_default(THD *thd, enum_var_type type) { + pthread_mutex_lock(guard); *value= (ulong) option_limits->def_value; + pthread_mutex_unlock(guard); } @@ -2642,6 +2666,14 @@ static byte *get_have_innodb(THD *thd) } +static byte *get_prepared_stmt_count(THD *thd) +{ + pthread_mutex_lock(&LOCK_prepared_stmt_count); + thd->sys_var_tmp.ulong_value= prepared_stmt_count; + pthread_mutex_unlock(&LOCK_prepared_stmt_count); + return (byte*) &thd->sys_var_tmp.ulong_value; +} + /**************************************************************************** Main handling of variables: - Initialisation diff --git a/sql/set_var.h b/sql/set_var.h index 2ac4fc2c260..c6319a79cf6 100644 --- a/sql/set_var.h +++ b/sql/set_var.h @@ -47,13 +47,7 @@ public: #if MYSQL_VERSION_ID < 50000 bool no_support_one_shot; #endif - sys_var(const char *name_arg) - :name(name_arg), after_update(0) -#if MYSQL_VERSION_ID < 50000 - , no_support_one_shot(1) -#endif - {} - sys_var(const char *name_arg,sys_after_update_func func) + sys_var(const char *name_arg, sys_after_update_func func= NULL) :name(name_arg), after_update(func) #if MYSQL_VERSION_ID < 50000 , no_support_one_shot(1) @@ -79,15 +73,35 @@ public: }; -class sys_var_long_ptr :public sys_var +/* + A base class for all variables that require its access to + be guarded with a mutex. +*/ + +class sys_var_global: public sys_var +{ +protected: + pthread_mutex_t *guard; +public: + sys_var_global(const char *name_arg, sys_after_update_func after_update_arg, + pthread_mutex_t *guard_arg) + :sys_var(name_arg, after_update_arg), guard(guard_arg) {} +}; + + +/* + A global-only ulong variable that requires its access to be + protected with a mutex. +*/ + +class sys_var_long_ptr_global: public sys_var_global { public: ulong *value; - sys_var_long_ptr(const char *name_arg, ulong *value_ptr) - :sys_var(name_arg),value(value_ptr) {} - sys_var_long_ptr(const char *name_arg, ulong *value_ptr, - sys_after_update_func func) - :sys_var(name_arg,func), value(value_ptr) {} + sys_var_long_ptr_global(const char *name_arg, ulong *value_ptr, + pthread_mutex_t *guard_arg, + sys_after_update_func after_update_arg= NULL) + :sys_var_global(name_arg, after_update_arg, guard_arg), value(value_ptr) {} bool check(THD *thd, set_var *var); bool update(THD *thd, set_var *var); void set_default(THD *thd, enum_var_type type); @@ -97,6 +111,18 @@ public: }; +/* + A global ulong variable that is protected by LOCK_global_system_variables +*/ + +class sys_var_long_ptr :public sys_var_long_ptr_global +{ +public: + sys_var_long_ptr(const char *name_arg, ulong *value_ptr, + sys_after_update_func after_update_arg= NULL); +}; + + class sys_var_ulonglong_ptr :public sys_var { public: @@ -175,7 +201,7 @@ class sys_var_const_str :public sys_var public: char *value; // Pointer to const value sys_var_const_str(const char *name_arg, const char *value_arg) - :sys_var(name_arg), value((char*) value_arg) + :sys_var(name_arg),value((char*) value_arg) {} bool check(THD *thd, set_var *var) { @@ -221,10 +247,7 @@ public: class sys_var_thd :public sys_var { public: - sys_var_thd(const char *name_arg) - :sys_var(name_arg) - {} - sys_var_thd(const char *name_arg, sys_after_update_func func) + sys_var_thd(const char *name_arg, sys_after_update_func func= NULL) :sys_var(name_arg,func) {} bool check_type(enum_var_type type) { return 0; } diff --git a/sql/sql_class.cc b/sql/sql_class.cc index 6e24e951aa4..d278ebe8dfa 100644 --- a/sql/sql_class.cc +++ b/sql/sql_class.cc @@ -1616,27 +1616,128 @@ Statement_map::Statement_map() : NULL,MYF(0)); } -int Statement_map::insert(Statement *statement) +/* + Insert a new statement to the thread-local statement map. + + DESCRIPTION + If there was an old statement with the same name, replace it with the + new one. Otherwise, check if max_prepared_stmt_count is not reached yet, + increase prepared_stmt_count, and insert the new statement. It's okay + to delete an old statement and fail to insert the new one. + + POSTCONDITIONS + All named prepared statements are also present in names_hash. + Statement names in names_hash are unique. + The statement is added only if prepared_stmt_count < max_prepard_stmt_count + last_found_statement always points to a valid statement or is 0 + + RETURN VALUE + 0 success + 1 error: out of resources or max_prepared_stmt_count limit has been + reached. An error is sent to the client, the statement is deleted. +*/ + +int Statement_map::insert(THD *thd, Statement *statement) { - int rc= my_hash_insert(&st_hash, (byte *) statement); - if (rc == 0) - last_found_statement= statement; + if (my_hash_insert(&st_hash, (byte*) statement)) + { + /* + Delete is needed only in case of an insert failure. In all other + cases hash_delete will also delete the statement. + */ + delete statement; + my_error(ER_OUT_OF_RESOURCES, MYF(0)); + goto err_st_hash; + } if (statement->name.str) { /* - If there is a statement with the same name, remove it. It is ok to + If there is a statement with the same name, remove it. It is ok to remove old and fail to insert new one at the same time. */ Statement *old_stmt; if ((old_stmt= find_by_name(&statement->name))) - erase(old_stmt); - if ((rc= my_hash_insert(&names_hash, (byte*)statement))) - hash_delete(&st_hash, (byte*)statement); + erase(old_stmt); + if (my_hash_insert(&names_hash, (byte*) statement)) + { + my_error(ER_OUT_OF_RESOURCES, MYF(0)); + goto err_names_hash; + } + } + pthread_mutex_lock(&LOCK_prepared_stmt_count); + /* + We don't check that prepared_stmt_count is <= max_prepared_stmt_count + because we would like to allow to lower the total limit + of prepared statements below the current count. In that case + no new statements can be added until prepared_stmt_count drops below + the limit. + */ + if (prepared_stmt_count >= max_prepared_stmt_count) + { + pthread_mutex_unlock(&LOCK_prepared_stmt_count); + my_error(ER_UNKNOWN_ERROR, MYF(0)); + goto err_max; + } + prepared_stmt_count++; + pthread_mutex_unlock(&LOCK_prepared_stmt_count); + + last_found_statement= statement; + return 0; + +err_max: + if (statement->name.str) + hash_delete(&names_hash, (byte*) statement); +err_names_hash: + hash_delete(&st_hash, (byte*) statement); +err_st_hash: + send_error(thd); + return 1; +} + + +void Statement_map::erase(Statement *statement) +{ + if (statement == last_found_statement) + last_found_statement= 0; + if (statement->name.str) + { + hash_delete(&names_hash, (byte *) statement); } - return rc; + hash_delete(&st_hash, (byte *) statement); + pthread_mutex_lock(&LOCK_prepared_stmt_count); + DBUG_ASSERT(prepared_stmt_count > 0); + prepared_stmt_count--; + pthread_mutex_unlock(&LOCK_prepared_stmt_count); +} + + +void Statement_map::reset() +{ + /* Must be first, hash_free will reset st_hash.records */ + pthread_mutex_lock(&LOCK_prepared_stmt_count); + DBUG_ASSERT(prepared_stmt_count >= st_hash.records); + prepared_stmt_count-= st_hash.records; + pthread_mutex_unlock(&LOCK_prepared_stmt_count); + + my_hash_reset(&names_hash); + my_hash_reset(&st_hash); + last_found_statement= 0; } +Statement_map::~Statement_map() +{ + /* Must go first, hash_free will reset st_hash.records */ + pthread_mutex_lock(&LOCK_prepared_stmt_count); + DBUG_ASSERT(prepared_stmt_count >= st_hash.records); + prepared_stmt_count-= st_hash.records; + pthread_mutex_unlock(&LOCK_prepared_stmt_count); + + hash_free(&names_hash); + hash_free(&st_hash); + +} + bool select_dumpvar::send_data(List<Item> &items) { List_iterator_fast<Item_func_set_user_var> li(vars); diff --git a/sql/sql_class.h b/sql/sql_class.h index 1bd7dcac03c..d482a524934 100644 --- a/sql/sql_class.h +++ b/sql/sql_class.h @@ -620,7 +620,7 @@ class Statement_map public: Statement_map(); - int insert(Statement *statement); + int insert(THD *thd, Statement *statement); Statement *find_by_name(LEX_STRING *name) { @@ -642,29 +642,10 @@ public: } return last_found_statement; } - void erase(Statement *statement) - { - if (statement == last_found_statement) - last_found_statement= 0; - if (statement->name.str) - { - hash_delete(&names_hash, (byte *) statement); - } - hash_delete(&st_hash, (byte *) statement); - } + void erase(Statement *statement); /* Erase all statements (calls Statement destructor) */ - void reset() - { - my_hash_reset(&names_hash); - my_hash_reset(&st_hash); - last_found_statement= 0; - } - - ~Statement_map() - { - hash_free(&names_hash); - hash_free(&st_hash); - } + void reset(); + ~Statement_map(); private: HASH st_hash; HASH names_hash; @@ -932,6 +913,7 @@ public: { my_bool my_bool_value; long long_value; + ulong ulong_value; } sys_var_tmp; THD(); diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc index 8a50d0bd50e..741d84eab44 100644 --- a/sql/sql_prepare.cc +++ b/sql/sql_prepare.cc @@ -1593,10 +1593,12 @@ int mysql_stmt_prepare(THD *thd, char *packet, uint packet_length, } } - if (thd->stmt_map.insert(stmt)) + if (thd->stmt_map.insert(thd, stmt)) { - delete stmt; - send_error(thd, ER_OUT_OF_RESOURCES); + /* + The error is sent in the insert. The statement itself + will be also deleted there (this is how the hash works). + */ DBUG_RETURN(1); } |