5.1.4 Server System Variable Reference

The following table lists all system variables applicable within mysqld.

The table lists command-line options (Cmd-line), options valid in configuration files (Option file), server system variables (System Var), and status variables (Status var) in one unified list, with an indication of where each option or variable is valid. If a server option set on the command line or in an option file differs from the name of the corresponding system variable, the variable name is noted immediately below the corresponding option. The scope of the variable (Var Scope) is Global, Session, or both. Please see the corresponding item descriptions for details on setting and using the variables. Where appropriate, direct links to further information about the items are provided.

Table 5.2 System Variable Summary

Name Cmd-Line Option File System Var Var Scope Dynamic
audit_log_buffer_size Yes Yes Yes Global No
audit_log_compression Yes Yes Yes Global No
audit_log_connection_policy Yes Yes Yes Global Yes
audit_log_current_session Yes Both No
audit_log_encryption Yes Yes Yes Global No
audit_log_exclude_accounts Yes Yes Yes Global Yes
audit_log_file Yes Yes Yes Global No
audit_log_filter_id Yes Both No
audit_log_flush Yes Global Yes
audit_log_format Yes Yes Yes Global No
audit_log_include_accounts Yes Yes Yes Global Yes
audit_log_policy Yes Yes Yes Global No
audit_log_read_buffer_size Yes Yes Yes Varies Varies
audit_log_rotate_on_size Yes Yes Yes Global Yes
audit_log_statement_policy Yes Yes Yes Global Yes
audit_log_strategy Yes Yes Yes Global No
authentication_ldap_sasl_auth_method_name Yes Yes Yes Global Yes
authentication_ldap_sasl_bind_base_dn Yes Yes Yes Global Yes
authentication_ldap_sasl_bind_root_dn Yes Yes Yes Global Yes
authentication_ldap_sasl_bind_root_pwd Yes Yes Yes Global Yes
authentication_ldap_sasl_ca_path Yes Yes Yes Global Yes
authentication_ldap_sasl_group_search_attr Yes Yes Yes Global Yes
authentication_ldap_sasl_group_search_filter Yes Yes Yes Global Yes
authentication_ldap_sasl_init_pool_size Yes Yes Yes Global Yes
authentication_ldap_sasl_log_status Yes Yes Yes Global Yes
authentication_ldap_sasl_max_pool_size Yes Yes Yes Global Yes
authentication_ldap_sasl_server_host Yes Yes Yes Global Yes
authentication_ldap_sasl_server_port Yes Yes Yes Global Yes
authentication_ldap_sasl_tls Yes Yes Yes Global Yes
authentication_ldap_sasl_user_search_attr Yes Yes Yes Global Yes
authentication_ldap_simple_auth_method_name Yes Yes Yes Global Yes
authentication_ldap_simple_bind_base_dn Yes Yes Yes Global Yes
authentication_ldap_simple_bind_root_dn Yes Yes Yes Global Yes
authentication_ldap_simple_bind_root_pwd Yes Yes Yes Global Yes
authentication_ldap_simple_ca_path Yes Yes Yes Global Yes
authentication_ldap_simple_group_search_attr Yes Yes Yes Global Yes
authentication_ldap_simple_group_search_filter Yes Yes Yes Global Yes
authentication_ldap_simple_init_pool_size Yes Yes Yes Global Yes
authentication_ldap_simple_log_status Yes Yes Yes Global Yes
authentication_ldap_simple_max_pool_size Yes Yes Yes Global Yes
authentication_ldap_simple_server_host Yes Yes Yes Global Yes
authentication_ldap_simple_server_port Yes Yes Yes Global Yes
authentication_ldap_simple_tls Yes Yes Yes Global Yes
authentication_ldap_simple_user_search_attr Yes Yes Yes Global Yes
authentication_windows_log_level Yes Yes Yes Global No
authentication_windows_use_principal_name Yes Yes Yes Global No
auto_generate_certs Yes Yes Yes Global No
auto_increment_increment Yes Yes Yes Both Yes
auto_increment_offset Yes Yes Yes Both Yes
autocommit Yes Yes Yes Both Yes
automatic_sp_privileges Yes Yes Yes Global Yes
avoid_temporal_upgrade Yes Yes Yes Global Yes
back_log Yes Yes Yes Global No
basedir Yes Yes Yes Global No
big_tables Yes Yes Yes Both Yes
bind_address Yes Yes Yes Global No
binlog_cache_size Yes Yes Yes Global Yes
binlog_checksum Yes Yes Yes Global Yes
binlog_direct_non_transactional_updates Yes Yes Yes Both Yes
binlog_error_action Yes Yes Yes Global Yes
binlog_format Yes Yes Yes Both Yes
binlog_group_commit_sync_delay Yes Yes Yes Global Yes
binlog_group_commit_sync_no_delay_count Yes Yes Yes Global Yes
binlog_gtid_simple_recovery Yes Yes Yes Global No
binlog_max_flush_queue_time Yes Yes Yes Global Yes
binlog_order_commits Yes Yes Yes Global Yes
binlog_row_image Yes Yes Yes Both Yes
binlog_rows_query_log_events Yes Yes Yes Both Yes
binlog_stmt_cache_size Yes Yes Yes Global Yes
binlog_transaction_dependency_history_size Yes Yes Yes Global Yes
binlog_transaction_dependency_tracking Yes Yes Yes Global Yes
block_encryption_mode Yes Yes Yes Both Yes
bulk_insert_buffer_size Yes Yes Yes Both Yes
character_set_client Yes Both Yes
character_set_connection Yes Both Yes
character_set_database (note 1) Yes Both Yes
character_set_filesystem Yes Yes Yes Both Yes
character_set_results Yes Both Yes
character_set_server Yes Yes Yes Both Yes
character_set_system Yes Global No
character_sets_dir Yes Yes Yes Global No
check_proxy_users Yes Yes Yes Global Yes
collation_connection Yes Both Yes
collation_database (note 1) Yes Both Yes
collation_server Yes Yes Yes Both Yes
completion_type Yes Yes Yes Both Yes
concurrent_insert Yes Yes Yes Global Yes
connect_timeout Yes Yes Yes Global Yes
connection_control_failed_connections_threshold Yes Yes Yes Global Yes
connection_control_max_connection_delay Yes Yes Yes Global Yes
connection_control_min_connection_delay Yes Yes Yes Global Yes
core_file Yes Global No
daemon_memcached_enable_binlog Yes Yes Yes Global No
daemon_memcached_engine_lib_name Yes Yes Yes Global No
daemon_memcached_engine_lib_path Yes Yes Yes Global No
daemon_memcached_option Yes Yes Yes Global No
daemon_memcached_r_batch_size Yes Yes Yes Global No
daemon_memcached_w_batch_size Yes Yes Yes Global No
datadir Yes Yes Yes Global No
date_format Yes Global No
datetime_format Yes Global No
debug Yes Yes Yes Both Yes
debug_sync Yes Session Yes
default_authentication_plugin Yes Yes Yes Global No
default_password_lifetime Yes Yes Yes Global Yes
default_storage_engine Yes Yes Yes Both Yes
default_tmp_storage_engine Yes Yes Yes Both Yes
default_week_format Yes Yes Yes Both Yes
delay_key_write Yes Yes Yes Global Yes
delayed_insert_limit Yes Yes Yes Global Yes
delayed_insert_timeout Yes Yes Yes Global Yes
delayed_queue_size Yes Yes Yes Global Yes
disabled_storage_engines Yes Yes Yes Global No
disconnect_on_expired_password Yes Yes Yes Global No
div_precision_increment Yes Yes Yes Both Yes
end_markers_in_json Yes Yes Yes Both Yes
enforce_gtid_consistency Yes Yes Yes Global Varies
eq_range_index_dive_limit Yes Yes Yes Both Yes
error_count Yes Session No
event_scheduler Yes Yes Yes Global Yes
expire_logs_days Yes Yes Yes Global Yes
explicit_defaults_for_timestamp Yes Yes Yes Both Yes
external_user Yes Session No
flush Yes Yes Yes Global Yes
flush_time Yes Yes Yes Global Yes
foreign_key_checks Yes Both Yes
ft_boolean_syntax Yes Yes Yes Global Yes
ft_max_word_len Yes Yes Yes Global No
ft_min_word_len Yes Yes Yes Global No
ft_query_expansion_limit Yes Yes Yes Global No
ft_stopword_file Yes Yes Yes Global No
general_log Yes Yes Yes Global Yes
general_log_file Yes Yes Yes Global Yes
group_concat_max_len Yes Yes Yes Both Yes
group_replication_allow_local_disjoint_gtids_join Yes Yes Yes Global Yes
group_replication_allow_local_lower_version_join Yes Yes Yes Global Yes
group_replication_auto_increment_increment Yes Yes Yes Global Yes
group_replication_bootstrap_group Yes Yes Yes Global Yes
group_replication_components_stop_timeout Yes Yes Yes Global Yes
group_replication_compression_threshold Yes Yes Yes Global Yes
group_replication_enforce_update_everywhere_checks Yes Yes Yes Global Yes
group_replication_exit_state_action Yes Yes Yes Global Yes
group_replication_flow_control_applier_threshold Yes Yes Yes Global Yes
group_replication_flow_control_certifier_threshold Yes Yes Yes Global Yes
group_replication_flow_control_mode Yes Yes Yes Global Yes
group_replication_force_members Yes Yes Yes Global Yes
group_replication_group_name Yes Yes Yes Global Yes
group_replication_group_seeds Yes Yes Yes Global Yes
group_replication_gtid_assignment_block_size Yes Yes Yes Global Yes
group_replication_ip_whitelist Yes Yes Yes Global Yes
group_replication_local_address Yes Yes Yes Global Yes
group_replication_member_weight Yes Yes Yes Global Yes
group_replication_poll_spin_loops Yes Yes Yes Global Yes
group_replication_recovery_complete_at Yes Yes Yes Global Yes
group_replication_recovery_reconnect_interval Yes Yes Yes Global Yes
group_replication_recovery_retry_count Yes Yes Yes Global Yes
group_replication_recovery_ssl_ca Yes Yes Yes Global Yes
group_replication_recovery_ssl_capath Yes Yes Yes Global Yes
group_replication_recovery_ssl_cert Yes Yes Yes Global Yes
group_replication_recovery_ssl_cipher Yes Yes Yes Global Yes
group_replication_recovery_ssl_crl Yes Yes Yes Global Yes
group_replication_recovery_ssl_crlpath Yes Yes Yes Global Yes
group_replication_recovery_ssl_key Yes Yes Yes Global Yes
group_replication_recovery_ssl_verify_server_cert Yes Yes Yes Global Yes
group_replication_recovery_use_ssl Yes Yes Yes Global Yes
group_replication_single_primary_mode Yes Yes Yes Global Yes
group_replication_ssl_mode Yes Yes Yes Global Yes
group_replication_start_on_boot Yes Yes Yes Global Yes
group_replication_transaction_size_limit Yes Yes Yes Global Yes
group_replication_unreachable_majority_timeout Yes Yes Yes Global Yes
gtid_executed Yes Varies No
gtid_executed_compression_period Yes Yes Yes Global Yes
gtid_mode Yes Yes Yes Global Varies
gtid_next Yes Session Yes
gtid_owned Yes Both No
gtid_purged Yes Global Yes
have_compress Yes Global No
have_crypt Yes Global No
have_dynamic_loading Yes Global No
have_geometry Yes Global No
have_openssl Yes Global No
have_profiling Yes Global No
have_query_cache Yes Global No
have_rtree_keys Yes Global No
have_ssl Yes Global No
have_statement_timeout Yes Global No
have_symlink Yes Global No
host_cache_size Yes Yes Yes Global Yes
hostname Yes Global No
identity Yes Session Yes
ignore_builtin_innodb Yes Yes Yes Global No
ignore_db_dirs Yes Global No
init_connect Yes Yes Yes Global Yes
init_file Yes Yes Yes Global No
init_slave Yes Yes Yes Global Yes
innodb_adaptive_flushing Yes Yes Yes Global Yes
innodb_adaptive_flushing_lwm Yes Yes Yes Global Yes
innodb_adaptive_hash_index Yes Yes Yes Global Yes
innodb_adaptive_hash_index_parts Yes Yes Yes Global No
innodb_adaptive_max_sleep_delay Yes Yes Yes Global Yes
innodb_api_bk_commit_interval Yes Yes Yes Global Yes
innodb_api_disable_rowlock Yes Yes Yes Global No
innodb_api_enable_binlog Yes Yes Yes Global No
innodb_api_enable_mdl Yes Yes Yes Global No
innodb_api_trx_level Yes Yes Yes Global Yes
innodb_autoextend_increment Yes Yes Yes Global Yes
innodb_autoinc_lock_mode Yes Yes Yes Global No
innodb_background_drop_list_empty Yes Yes Yes Global Yes
innodb_buffer_pool_chunk_size Yes Yes Yes Global No
innodb_buffer_pool_dump_at_shutdown Yes Yes Yes Global Yes
innodb_buffer_pool_dump_now Yes Yes Yes Global Yes
innodb_buffer_pool_dump_pct Yes Yes Yes Global Yes
innodb_buffer_pool_filename Yes Yes Yes Global Yes
innodb_buffer_pool_instances Yes Yes Yes Global No
innodb_buffer_pool_load_abort Yes Yes Yes Global Yes
innodb_buffer_pool_load_at_startup Yes Yes Yes Global No
innodb_buffer_pool_load_now Yes Yes Yes Global Yes
innodb_buffer_pool_size Yes Yes Yes Global Varies
innodb_change_buffer_max_size Yes Yes Yes Global Yes
innodb_change_buffering Yes Yes Yes Global Yes
innodb_change_buffering_debug Yes Yes Yes Global Yes
innodb_checksum_algorithm Yes Yes Yes Global Yes
innodb_checksums Yes Yes Yes Global No
innodb_cmp_per_index_enabled Yes Yes Yes Global Yes
innodb_commit_concurrency Yes Yes Yes Global Yes
innodb_compress_debug Yes Yes Yes Global Yes
innodb_compression_failure_threshold_pct Yes Yes Yes Global Yes
innodb_compression_level Yes Yes Yes Global Yes
innodb_compression_pad_pct_max Yes Yes Yes Global Yes
innodb_concurrency_tickets Yes Yes Yes Global Yes
innodb_data_file_path Yes Yes Yes Global No
innodb_data_home_dir Yes Yes Yes Global No
innodb_deadlock_detect Yes Yes Yes Global Yes
innodb_default_row_format Yes Yes Yes Global Yes
innodb_disable_resize_buffer_pool_debug Yes Yes Yes Global Yes
innodb_disable_sort_file_cache Yes Yes Yes Global Yes
innodb_doublewrite Yes Yes Yes Global No
innodb_fast_shutdown Yes Yes Yes Global Yes
innodb_fil_make_page_dirty_debug Yes Yes Yes Global Yes
innodb_file_format Yes Yes Yes Global Yes
innodb_file_format_check Yes Yes Yes Global No
innodb_file_format_max Yes Yes Yes Global Yes
innodb_file_per_table Yes Yes Yes Global Yes
innodb_fill_factor Yes Yes Yes Global Yes
innodb_flush_log_at_timeout Yes Yes Yes Global Yes
innodb_flush_log_at_trx_commit Yes Yes Yes Global Yes
innodb_flush_method Yes Yes Yes Global No
innodb_flush_neighbors Yes Yes Yes Global Yes
innodb_flush_sync Yes Yes Yes Global Yes
innodb_flushing_avg_loops Yes Yes Yes Global Yes
innodb_force_load_corrupted Yes Yes Yes Global No
innodb_force_recovery Yes Yes Yes Global No
innodb_ft_aux_table Yes Global Yes
innodb_ft_cache_size Yes Yes Yes Global No
innodb_ft_enable_diag_print Yes Yes Yes Global Yes
innodb_ft_enable_stopword Yes Yes Yes Both Yes
innodb_ft_max_token_size Yes Yes Yes Global No
innodb_ft_min_token_size Yes Yes Yes Global No
innodb_ft_num_word_optimize Yes Yes Yes Global Yes
innodb_ft_result_cache_limit Yes Yes Yes Global Yes
innodb_ft_server_stopword_table Yes Yes Yes Global Yes
innodb_ft_sort_pll_degree Yes Yes Yes Global No
innodb_ft_total_cache_size Yes Yes Yes Global No
innodb_ft_user_stopword_table Yes Yes Yes Both Yes
innodb_io_capacity Yes Yes Yes Global Yes
innodb_io_capacity_max Yes Yes Yes Global Yes
innodb_large_prefix Yes Yes Yes Global Yes
innodb_limit_optimistic_insert_debug Yes Yes Yes Global Yes
innodb_lock_wait_timeout Yes Yes Yes Both Yes
innodb_locks_unsafe_for_binlog Yes Yes Yes Global No
innodb_log_buffer_size Yes Yes Yes Global No
innodb_log_checkpoint_now Yes Yes Yes Global Yes
innodb_log_checksums Yes Yes Yes Global Yes
innodb_log_compressed_pages Yes Yes Yes Global Yes
innodb_log_file_size Yes Yes Yes Global No
innodb_log_files_in_group Yes Yes Yes Global No
innodb_log_group_home_dir Yes Yes Yes Global No
innodb_log_write_ahead_size Yes Yes Yes Global Yes
innodb_lru_scan_depth Yes Yes Yes Global Yes
innodb_max_dirty_pages_pct Yes Yes Yes Global Yes
innodb_max_dirty_pages_pct_lwm Yes Yes Yes Global Yes
innodb_max_purge_lag Yes Yes Yes Global Yes
innodb_max_purge_lag_delay Yes Yes Yes Global Yes
innodb_max_undo_log_size Yes Yes Yes Global Yes
innodb_merge_threshold_set_all_debug Yes Yes Yes Global Yes
innodb_monitor_disable Yes Yes Yes Global Yes
innodb_monitor_enable Yes Yes Yes Global Yes
innodb_monitor_reset Yes Yes Yes Global Yes
innodb_monitor_reset_all Yes Yes Yes Global Yes
innodb_numa_interleave Yes Yes Yes Global No
innodb_old_blocks_pct Yes Yes Yes Global Yes
innodb_old_blocks_time Yes Yes Yes Global Yes
innodb_online_alter_log_max_size Yes Yes Yes Global Yes
innodb_open_files Yes Yes Yes Global No
innodb_optimize_fulltext_only Yes Yes Yes Global Yes
innodb_page_cleaners Yes Yes Yes Global No
innodb_page_size Yes Yes Yes Global No
innodb_print_all_deadlocks Yes Yes Yes Global Yes
innodb_purge_batch_size Yes Yes Yes Global Yes
innodb_purge_rseg_truncate_frequency Yes Yes Yes Global Yes
innodb_purge_threads Yes Yes Yes Global No
innodb_random_read_ahead Yes Yes Yes Global Yes
innodb_read_ahead_threshold Yes Yes Yes Global Yes
innodb_read_io_threads Yes Yes Yes Global No
innodb_read_only Yes Yes Yes Global No
innodb_replication_delay Yes Yes Yes Global Yes
innodb_rollback_on_timeout Yes Yes Yes Global No
innodb_rollback_segments Yes Yes Yes Global Yes
innodb_saved_page_number_debug Yes Yes Yes Global Yes
innodb_sort_buffer_size Yes Yes Yes Global No
innodb_spin_wait_delay Yes Yes Yes Global Yes
innodb_stats_auto_recalc Yes Yes Yes Global Yes
innodb_stats_include_delete_marked Yes Yes Yes Global Yes
innodb_stats_method Yes Yes Yes Global Yes
innodb_stats_on_metadata Yes Yes Yes Global Yes
innodb_stats_persistent Yes Yes Yes Global Yes
innodb_stats_persistent_sample_pages Yes Yes Yes Global Yes
innodb_stats_sample_pages Yes Yes Yes Global Yes
innodb_stats_transient_sample_pages Yes Yes Yes Global Yes
innodb_status_output Yes Yes Yes Global Yes
innodb_status_output_locks Yes Yes Yes Global Yes
innodb_strict_mode Yes Yes Yes Both Yes
innodb_support_xa Yes Yes Yes Both Yes
innodb_sync_array_size Yes Yes Yes Global No
innodb_sync_debug Yes Yes Yes Global No
innodb_sync_spin_loops Yes Yes Yes Global Yes
innodb_table_locks Yes Yes Yes Both Yes
innodb_temp_data_file_path Yes Yes Yes Global No
innodb_thread_concurrency Yes Yes Yes Global Yes
innodb_thread_sleep_delay Yes Yes Yes Global Yes
innodb_tmpdir Yes Yes Yes Both Yes
innodb_trx_purge_view_update_only_debug Yes Yes Yes Global Yes
innodb_trx_rseg_n_slots_debug Yes Yes Yes Global Yes
innodb_undo_directory Yes Yes Yes Global No
innodb_undo_log_truncate Yes Yes Yes Global Yes
innodb_undo_logs Yes Yes Yes Global Yes
innodb_undo_tablespaces Yes Yes Yes Global No
innodb_use_native_aio Yes Yes Yes Global No
innodb_version Yes Global No
innodb_write_io_threads Yes Yes Yes Global No
insert_id Yes Session Yes
interactive_timeout Yes Yes Yes Both Yes
internal_tmp_disk_storage_engine Yes Yes Yes Global Yes
join_buffer_size Yes Yes Yes Both Yes
keep_files_on_create Yes Yes Yes Both Yes
key_buffer_size Yes Yes Yes Global Yes
key_cache_age_threshold Yes Yes Yes Global Yes
key_cache_block_size Yes Yes Yes Global Yes
key_cache_division_limit Yes Yes Yes Global Yes
keyring_aws_cmk_id Yes Yes Yes Global Yes
keyring_aws_conf_file Yes Yes Yes Global No
keyring_aws_data_file Yes Yes Yes Global No
keyring_aws_region Yes Yes Yes Global Yes
keyring_encrypted_file_data Yes Yes Yes Global Yes
keyring_encrypted_file_password Yes Yes Yes Global Yes
keyring_file_data Yes Yes Yes Global Yes
keyring_okv_conf_dir Yes Yes Yes Global Yes
keyring_operations Yes Global Yes
language Yes Yes Yes Global No
large_files_support Yes Global No
large_page_size Yes Global No
large_pages Yes Yes Yes Global No
last_insert_id Yes Session Yes
lc_messages Yes Yes Yes Both Yes
lc_messages_dir Yes Yes Yes Global No
lc_time_names Yes Yes Yes Both Yes
license Yes Global No
local_infile Yes Yes Yes Global Yes
lock_wait_timeout Yes Yes Yes Both Yes
locked_in_memory Yes Global No
log_bin Yes Global No
log_bin_basename Yes Global No
log_bin_index Yes Yes Yes Global No
log_bin_trust_function_creators Yes Yes Yes Global Yes
log_bin_use_v1_row_events Yes Yes Yes Global No
log_builtin_as_identified_by_password Yes Yes Yes Global Yes
log_error Yes Yes Yes Global No
log_error_verbosity Yes Yes Yes Global Yes
log_output Yes Yes Yes Global Yes
log_queries_not_using_indexes Yes Yes Yes Global Yes
log_slave_updates Yes Yes Yes Global No
log_slow_admin_statements Yes Yes Yes Global Yes
log_slow_slave_statements Yes Yes Yes Global Yes
log_statements_unsafe_for_binlog Yes Yes Yes Global Yes
log_syslog Yes Yes Yes Global Yes
log_syslog_facility Yes Yes Yes Global Yes
log_syslog_include_pid Yes Yes Yes Global Yes
log_syslog_tag Yes Yes Yes Global Yes
log_throttle_queries_not_using_indexes Yes Yes Yes Global Yes
log_timestamps Yes Yes Yes Global Yes
log_warnings Yes Yes Yes Global Yes
long_query_time Yes Yes Yes Both Yes
low_priority_updates Yes Yes Yes Both Yes
lower_case_file_system Yes Global No
lower_case_table_names Yes Yes Yes Global No
master_info_repository Yes Yes Yes Global Yes
master_verify_checksum Yes Yes Yes Global Yes
max_allowed_packet Yes Yes Yes Both Yes
max_binlog_cache_size Yes Yes Yes Global Yes
max_binlog_size Yes