許多服務器系統變量是動態的,可以使用SET GLOBAL或SET SESSION在運行時設置。你還可以使用SELECT獲得它們的值。參見9.4節,“系統變量”。
下面的表列出了所有動態系統變量。最后1列說明每個變量是否適用GLOBAL或SESSION(或二者)。
|
變量名 |
值類型 |
類型 |
|
autocommit |
boolean |
SESSION |
|
big_tables |
boolean |
SESSION |
|
binlog_cache_size |
numeric |
GLOBAL |
|
bulk_insert_buffer_size |
numeric |
GLOBAL | SESSION |
|
character_set_client |
string |
GLOBAL | SESSION |
|
character_set_connection |
string |
GLOBAL | SESSION |
|
character_set_results |
string |
GLOBAL | SESSION |
|
character_set_server |
string |
GLOBAL | SESSION |
|
collation_connection |
string |
GLOBAL | SESSION |
|
collation_server |
string |
GLOBAL | SESSION |
|
completion_type |
numeric |
GLOBAL | SESSION |
|
concurrent_insert |
boolean |
GLOBAL |
|
connect_timeout |
numeric |
GLOBAL |
|
convert_character_set |
string |
GLOBAL | SESSION |
|
default_week_format |
numeric |
GLOBAL | SESSION |
|
delay_key_write |
OFF | ON | ALL |
GLOBAL |
|
delayed_insert_limit |
numeric |
GLOBAL |
|
delayed_insert_timeout |
numeric |
GLOBAL |
|
delayed_queue_size |
numeric |
GLOBAL |
|
div_precision_increment |
numeric |
GLOBAL | SESSION |
|
engine_condition_pushdown |
boolean |
GLOBAL | SESSION |
|
error_count |
numeric |
SESSION |
|
expire_logs_days |
numeric |
GLOBAL |
|
flush |
boolean |
GLOBAL |
|
flush_time |
numeric |
GLOBAL |
|
foreign_key_checks |
boolean |
SESSION |
|
ft_boolean_syntax |
numeric |
GLOBAL |
|
group_concat_max_len |
numeric |
GLOBAL | SESSION |
|
identity |
numeric |
SESSION |
|
innodb_autoextend_increment |
numeric |
GLOBAL |
|
innodb_concurrency_tickets |
numeric |
GLOBAL |
|
innodb_max_dirty_pages_pct |
numeric |
GLOBAL |
|
innodb_max_purge_lag |
numeric |
GLOBAL |
|
innodb_support_xa |
boolean |
GLOBAL | SESSION |
|
innodb_sync_spin_loops |
numeric |
GLOBAL |
|
innodb_table_locks |
boolean |
GLOBAL | SESSION |
|
innodb_thread_concurrency |
numeric GLOBAL |
|
|
innodb_thread_sleep_delay |
numeric GLOBAL |
|
|
insert_id |
boolean |
SESSION |
|
interactive_timeout |
numeric |
GLOBAL | SESSION |
|
join_buffer_size |
numeric |
GLOBAL | SESSION |
|
key_buffer_size |
numeric |
GLOBAL |
|
last_insert_id |
numeric |
SESSION |
|
local_infile |
boolean |
GLOBAL |
|
log_warnings |
numeric |
GLOBAL |
|
long_query_time |
numeric |
GLOBAL | SESSION |
|
low_priority_updates |
boolean |
GLOBAL | SESSION |
|
max_allowed_packet |
numeric |
GLOBAL | SESSION |
|
max_binlog_cache_size |
numeric |
GLOBAL |
|
max_binlog_size |
numeric |
GLOBAL |
|
max_connect_errors |
numeric |
GLOBAL |
|
max_connections |
numeric |
GLOBAL |
|
max_delayed_threads |
numeric |
GLOBAL |
|
max_error_count |
numeric |
GLOBAL | SESSION |
|
max_heap_table_size |
numeric |
GLOBAL | SESSION |
|
max_insert_delayed_threads |
numeric |
GLOBAL |
|
max_join_size |
numeric |
GLOBAL | SESSION |
|
max_relay_log_size |
numeric |
GLOBAL |
|
max_seeks_for_key |
numeric |
GLOBAL | SESSION |
|
max_sort_length |
numeric |
GLOBAL | SESSION |
|
max_tmp_tables |
numeric |
GLOBAL | SESSION |
|
max_user_connections |
numeric |
GLOBAL |
|
max_write_lock_count |
numeric |
GLOBAL |
|
myisam_stats_method |
enum |
GLOBAL | SESSION |
|
multi_read_range |
numeric |
GLOBAL | SESSION |
|
myisam_data_pointer_size |
numeric |
GLOBAL |
|
log_bin_trust_routine_creators |
boolean |
GLOBAL |
|
myisam_max_sort_file_size |
numeric |
GLOBAL | SESSION |
|
myisam_repair_threads |
numeric |
GLOBAL | SESSION |
|
myisam_sort_buffer_size |
numeric |
GLOBAL | SESSION |
|
net_buffer_length |
numeric |
GLOBAL | SESSION |
|
net_read_timeout |
numeric |
GLOBAL | SESSION |
|
net_retry_count |
numeric |
GLOBAL | SESSION |
|
net_write_timeout |
numeric |
GLOBAL | SESSION |
|
old_passwords |
numeric |
GLOBAL | SESSION |
|
optimizer_prune_level |
numeric |
GLOBAL | SESSION |
|
optimizer_search_depth |
numeric |
GLOBAL | SESSION |
|
preload_buffer_size |
numeric |
GLOBAL | SESSION |
|
query_alloc_block_size |
numeric |
GLOBAL | SESSION |
|
query_cache_limit |
numeric |
GLOBAL |
|
query_cache_size |
numeric |
GLOBAL |
|
query_cache_type |
enumeration |
GLOBAL | SESSION |
|
query_cache_wlock_invalidate |
boolean |
GLOBAL | SESSION |
|
query_prealloc_size |
numeric |
GLOBAL | SESSION |
|
range_alloc_block_size |
numeric |
GLOBAL | SESSION |
|
read_buffer_size |
numeric |
GLOBAL | SESSION |
|
read_only |
numeric |
GLOBAL |
|
read_rnd_buffer_size |
numeric |
GLOBAL | SESSION |
|
rpl_recovery_rank |
numeric |
GLOBAL |
|
safe_show_database |
boolean |
GLOBAL |
|
secure_auth |
boolean |
GLOBAL |
|
server_id |
numeric |
GLOBAL |
|
slave_compressed_protocol |
boolean |
GLOBAL |
|
slave_net_timeout |
numeric |
GLOBAL |
|
slave_transaction_retries |
numeric |
GLOBAL |
|
slow_launch_time |
numeric |
GLOBAL |
|
sort_buffer_size |
numeric |
GLOBAL | SESSION |
|
sql_auto_is_null |
boolean |
SESSION |
|
sql_big_selects |
boolean |
SESSION |
|
sql_big_tables |
boolean |
SESSION |
|
sql_buffer_result |
boolean |
SESSION |
|
sql_log_bin |
boolean |
SESSION |
|
sql_log_off |
boolean |
SESSION |
|
sql_log_update |
boolean |
SESSION |
|
sql_low_priority_updates |
boolean |
GLOBAL | SESSION |
|
sql_max_join_size |
numeric |
GLOBAL | SESSION |
|
sql_mode |
enumeration |
GLOBAL | SESSION |
|
sql_notes |
boolean |
SESSION |
|
sql_quote_show_create |
boolean |
SESSION |
|
sql_safe_updates |
boolean |
SESSION |
|
sql_select_limit |
numeric |
SESSION |
|
sql_slave_skip_counter |
numeric |
GLOBAL |
|
updatable_views_with_limit |
enumeration |
GLOBAL | SESSION |
|
sql_warnings |
boolean |
SESSION |
|
sync_binlog |
numeric |
GLOBAL |
|
sync_frm |
boolean |
GLOBAL |
|
storage_engine |
enumeration |
GLOBAL | SESSION |
|
table_cache |
numeric |
GLOBAL |
|
table_type |
enumeration |
GLOBAL | SESSION |
|
thread_cache_size |
numeric |
GLOBAL |
|
time_zone |
string |
GLOBAL | SESSION |
|
timestamp |
boolean |
SESSION |
|
tmp_table_size |
enumeration |
GLOBAL | SESSION |
|
transaction_alloc_block_size |
numeric |
GLOBAL | SESSION |
|
transaction_prealloc_size |
numeric |
GLOBAL | SESSION |
|
tx_isolation |
enumeration |
GLOBAL | SESSION |
|
unique_checks |
boolean |
SESSION |
|
wait_timeout |
numeric |
GLOBAL | SESSION |
|
warning_count |
numeric |
SESSION |
標記為string的變量采用字符串值。標記為numeric的變量采用數字值。標記為boolean的變量可以設置為0、1、ON或OFF。標記為enumeration的變量一般情況應設置為該變量的某個可用值,但還可以設置為對應期望的枚舉值的數字。對于枚舉系統變量,第1個枚舉值應對應0。這不同于ENUM列,第1個枚舉值對應1。