8:mysqld
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mysqld - the MySQL server
mysqld [options]
Contents |
DESCRIPTION
mysqld is the MySQL server. The following discussion covers these MySQL server configuration topics:
� Startup options that the server supports
� Server system variables
� Server status variables
� How to set the server SQL mode
� The server shutdown process
Note: Not all storage engines are supported by all MySQL server binaries and configurations. To find out how to determine which storage engines are supported by your MySQL server installation, see Section 5.4.10, "SHOW ENGINES Syntax".
OPTION AND VARIABLE REFERENCE
The following table provides a list of all the command line options, server and status variables applicable
within mysqld.
The table lists command line options (Cmd-line), options valid in configuration files (Option file), server
system variables (Server Var), and status variables (Status var) in one unified list, with notification of where
each option/variable is valid. If a server option set on the command line or in an option file differs from the
name of the corresponding server system or status variable, the variable name is noted immediately below the
corresponding option. Please see the corresponding sections for details on setting and using the options and
variables. Where appropriate, a direct link to further information on the item as available.
Note
This table is part of an ongoing process to expand and simplify the information provided on these elements.
Further improvements to the table, and corresponding descriptions will be applied over the coming months.
allbox tab(:); lB cB cB cB cB l. T{ Name T}:T{ Cmd-line T}:T{ Option file T}:T{ Server Var T}:T{ Status Var
T}:T{ T} l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c
c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l l c c c c l
l c c c c l l c c c c l. T{ abort-slave-event-count T}:T{ Y T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ back_log T}:T{
Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Com_replace T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_replace_select T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_reset T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{
T} T{ Com_restore_table T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_revoke T}:T{ T}:T{ T}:T{ T}:T{
Y T}:T{ T} T{ Com_revoke_all T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_rollback T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_savepoint T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_select T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_set_option T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ basedir T}:T{ Y T}:T{
Y T}:T{ Y T}:T{ T}:T{ T} T{ Com_show_binlog_events T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_show_binlogs T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_charsets T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ Com_show_collations T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_column_types T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_create_db T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_show_create_event T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_create_table T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_show_databases T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_engine_logs T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ bdb T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ Com_show_engine_mutex
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_engine_status T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T}
T{ Com_show_errors T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_events T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ Com_show_fields T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_grants T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_show_keys T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_master_status T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_new_master T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_show_open_tables T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ - Variable: have_bdb T}:T{ T}:T{ T}:T{ Y
T}:T{ T}:T{ T} T{ Com_show_plugins T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_privileges T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_processlist T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_show_slave_hosts T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_slave_status T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_show_status T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_storage_engines
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_tables T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_show_triggers T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_show_variables T}:T{ T}:T{ T}:T{ T}:T{
Y T}:T{ T} T{ bdb-home T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ Com_show_warnings T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_slave_start T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_slave_stop T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_stmt_close T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_stmt_execute
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_stmt_fetch T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_stmt_prepare T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_stmt_reset T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ Com_stmt_send_long_data T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_truncate T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ - Variable: bdb_home T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
Com_unlock_tables T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_update T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{
T} T{ Com_update_multi T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_xa_commit T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_xa_end T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_xa_prepare T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_xa_recover T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_xa_rollback T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_xa_start T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
completion-type T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ bdb-lock-detect T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ Compression T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ concurrent-insert T}:T{ Y T}:T{ Y T}:T{
T}:T{ T}:T{ T} T{ - Variable: concurrent_insert T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ connect_timeout
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Connections T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ console
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ core-file T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
Created_tmp_disk_tables T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Created_tmp_files T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Created_tmp_tables T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ bdb-logdir T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T}:T{ T} T{ datadir T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ date_format T}:T{ Y T}:T{
T}:T{ Y T}:T{ T}:T{ T} T{ datetime_format T}:T{ Y T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ default-character-set
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ default-collation T}:T{ Y T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
default-storage-engine T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ default-table-type T}:T{ Y T}:T{ Y T}:T{
T}:T{ T}:T{ T} T{ default-time-zone T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ default_week_format T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ defaults-extra-file T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ -
Variable: bdb_logdir T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ defaults-file T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ delay-key-write T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: delay_key_write T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ delay-key-write-for-all-tables T}:T{ Y T}:T{ T}:T{ T}:T{ T}:T{ T}
T{ Delayed_errors T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ delayed_insert_limit T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ Delayed_insert_threads T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ delayed_insert_timeout
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ delayed_queue_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
Delayed_writes T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ bdb-no-recover T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{
T} T{ des-key-file T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ disconnect-slave-event-count T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T}:T{ T} T{ div_precision_increment T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
enable-locking T}:T{ Y T}:T{ T}:T{ T}:T{ T}:T{ T} T{ enable-pstack T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{
T} T{ engine-condition-pushdown T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable:
engine_condition_pushdown T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ error_count T}:T{ T}:T{ T}:T{ T}:T{
Y T}:T{ T} T{ exit-info T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ expire_logs_days T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ Aborted_clients T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ bdb-no-sync T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T}:T{ T} T{ external-locking T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ flush T}:T{ Y T}:T{
Y T}:T{ Y T}:T{ T}:T{ T} T{ Flush_commands T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ flush_time T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ foreign_key_checks T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
ft_boolean_syntax T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ ft_max_word_len T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ ft_min_word_len T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ ft_query_expansion_limit T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ ft_stopword_file T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
bdb-shared-data T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ gdb T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
group_concat_max_len T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Handler_commit T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ Handler_delete T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_discover T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Handler_prepare T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_read_first T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_read_key T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Handler_read_next T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_read_prev T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ - Variable: bdb_shared_data T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ Handler_read_rnd T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_read_rnd_next T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Handler_rollback T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_savepoint T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ Handler_savepoint_rollback T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_update T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Handler_write T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ help T}:T{ Y
T}:T{ T}:T{ T}:T{ T}:T{ T} T{ identity T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ init-connect T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ bdb-tmpdir T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable:
init_connect T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ init-file T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T}
T{ - Variable: init_file T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ init-rpl-role T}:T{ Y T}:T{ Y T}:T{
T}:T{ T}:T{ T} T{ init-slave T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: init_slave T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ innodb T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
innodb_additional_mem_pool_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_autoextend_increment T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_buffer_pool_awe_mem_mb T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
- Variable: bdb_tmpdir T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ innodb_buffer_pool_size T}:T{ Y T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T} T{ innodb_checksums T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
innodb_commit_concurrency T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_concurrency_tickets T}:T{ Y T}:T{
Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_data_file_path T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
innodb_data_home_dir T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_doublewrite T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ innodb_fast_shutdown T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_file_io_threads
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_file_per_table T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
bdb_cache_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_flush_log_at_trx_commit T}:T{ Y T}:T{ Y T}:T{
Y T}:T{ T}:T{ T} T{ innodb_flush_method T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_force_recovery
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_lock_wait_timeout T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}
T{ innodb_locks_unsafe_for_binlog T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_log_arch_dir T}:T{ Y T}:T{
Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_log_archive T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
innodb_log_buffer_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_log_file_size T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ innodb_log_files_in_group T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ bdb_lock_max T}:T{
Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_log_group_home_dir T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
innodb_max_dirty_pages_pct T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_max_purge_lag T}:T{ Y T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T} T{ innodb_mirrored_log_groups T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
innodb_open_files T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_status_file T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ innodb_support_xa T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_sync_spin_loops T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ innodb_table_locks T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
innodb_thread_concurrency T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ bdb_log_buffer_size T}:T{ Y T}:T{ Y T}:T{
Y T}:T{ T}:T{ T} T{ innodb_thread_sleep_delay T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ insert_id T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ interactive_timeout T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ isam
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ join_buffer_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
Key_blocks_not_flushed T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Key_blocks_unused T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Key_blocks_used T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ key_buffer_size T}:T{ Y T}:T{
Y T}:T{ Y T}:T{ T}:T{ T} T{ key_cache_age_threshold T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
bdb_max_lock T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ key_cache_block_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ key_cache_division_limit T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Key_read_requests T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Key_reads T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Key_write_requests
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Key_writes T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ language
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ large-pages T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
last_insert_id T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ Last_query_cost T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ big-tables T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ license T}:T{ T}:T{ T}:T{ Y T}:T{
T}:T{ T} T{ local-infile T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: local_infile T}:T{ T}:T{
T}:T{ Y T}:T{ T}:T{ T} T{ log T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ log-bin T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ log-bin-index T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ log-bin-trust-function-creators
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: log_bin_trust_function_creators T}:T{ T}:T{ T}:T{ Y
T}:T{ T}:T{ T} T{ log-bin-trust-routine-creators T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ log-error
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Aborted_connects T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ -
Variable: big_tables T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ log-isam T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ log-long-format T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ log-short-format T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ log-slave-updates T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ log-slow-admin-statements
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ log-slow-queries T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ -
Variable: log_slow_queries T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ log-tc T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ log-tc-size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ log-update T}:T{ Y T}:T{ T}:T{ Y T}:T{
T}:T{ T} T{ bind-address T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ log-warnings T}:T{ Y T}:T{ Y T}:T{
T}:T{ T}:T{ T} T{ - Variable: log_warnings T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ long_query_time
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ low-priority-updates T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
- Variable: low_priority_updates T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ lower_case_table_names T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ master-connect-retry T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
master-host T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ master-info-file T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ master-password T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ binlog-do-db T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ master-port T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ master-retry-count T}:T{ Y T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T} T{ master-ssl T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ master-ssl-ca T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ master-ssl-capath T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
master-ssl-cert T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ master-ssl-cipher T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ master-ssl-key T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ master-user T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ max-binlog-dump-events T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ binlog-ignore-db T}:T{
Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ max_allowed_packet T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
max_binlog_cache_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_binlog_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ max_connect_errors T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_connections T}:T{ Y T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T} T{ max_delayed_threads T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_error_count
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_heap_table_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
max_insert_delayed_threads T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ max_join_size T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ Binlog_cache_disk_use T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
max_length_for_sort_data T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_prepared_stmt_count T}:T{ Y T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T} T{ max_relay_log_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_seeks_for_key
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_sort_length T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
max_sp_recursion_depth T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_tmp_tables T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ Max_used_connections T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ max_user_connections T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ max_write_lock_count T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
binlog_cache_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ memlock T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{
T} T{ - Variable: locked_in_memory T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ merge T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ multi_range_count T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ multi_read_range T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ myisam-recover T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
myisam_block_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ myisam_data_pointer_size T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ myisam_max_extra_sort_file_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
myisam_max_sort_file_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Binlog_cache_use T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ myisam_repair_threads T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ myisam_sort_buffer_size
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ myisam_stats_method T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
ndb-autoincrement-prefetch-sz T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ ndb-cache-check-time T}:T{ T}:T{
T}:T{ Y T}:T{ T}:T{ T} T{ ndb-connectstring T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ ndb-distribution
T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ ndb-index-stat-cache-entries T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{
T} T{ ndb-index-stat-enable T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ ndb-index-stat-update-freq T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ bootstrap T}:T{ Y T}:T{ T}:T{ T}:T{ T}:T{ T} T{ ndb-mgmd-host T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ ndb-optimized-node-selection T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T}
T{ ndb-report-thresh-binlog-epoch-slip3 T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
ndb-report-thresh-binlog-mem-usage10 T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ ndb_extra_logging T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ ndb_use_exact_count T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
ndbcluster T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ net_buffer_length T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ net_read_timeout T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ net_retry_count T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ bulk_insert_buffer_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ net_write_timeout
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ new T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ no-defaults T}:T{
Y T}:T{ T}:T{ T}:T{ T}:T{ T} T{ Not_flushed_delayed_rows T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
old-passwords T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: old_passwords T}:T{ T}:T{ T}:T{ Y
T}:T{ T}:T{ T} T{ old-style-user-limits T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Open_files T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ open_files_limit T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Open_streams
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Bytes_received T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Open_table_definitions T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Open_tables T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ Opened_tables T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ optimizer_prune_level T}:T{ Y T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T} T{ optimizer_search_depth T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ pid-file T}:T{
Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ port T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ port-open-timeout
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ preload_buffer_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
print-defaults T}:T{ Y T}:T{ T}:T{ T}:T{ T}:T{ T} T{ allow-suspicious-udfs T}:T{ Y T}:T{ T}:T{ Y T}:T{
T}:T{ T} T{ Bytes_sent T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Qcache_free_blocks T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Qcache_free_memory T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Qcache_hits T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Qcache_inserts T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Qcache_lowmem_prunes T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Qcache_not_cached T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Qcache_queries_in_cache T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Qcache_total_blocks
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ query_alloc_block_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}
T{ query_cache_limit T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ character-set-client-handshake T}:T{ Y T}:T{
T}:T{ T}:T{ T}:T{ T} T{ query_cache_min_res_unit T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
query_cache_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ query_cache_type T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ query_cache_wlock_invalidate T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ query_prealloc_size
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Questions T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
range_alloc_block_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ read_buffer_size T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ read_only T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ read_rnd_buffer_size T}:T{ Y T}:T{
Y T}:T{ Y T}:T{ T}:T{ T} T{ character-set-filesystem T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
record_buffer T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ relay-log T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}
T{ relay-log-index T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ relay-log-info-file T}:T{ Y T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T} T{ relay_log_purge T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ relay_log_space_limit T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ replicate-do-db T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
replicate-do-table T}:T{ Y T}:T{ T}:T{ T}:T{ T}:T{ T} T{ replicate-ignore-db T}:T{ Y T}:T{ Y T}:T{
T}:T{ T}:T{ T} T{ replicate-ignore-table T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ character-set-server
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ replicate-rewrite-db T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
replicate-same-server-id T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ replicate-wild-do-table T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T}:T{ T} T{ replicate-wild-ignore-table T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
report-host T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ report-password T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ report-port T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ report-user T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ rpl-recovery-rank T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: rpl_recovery_rank T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ - Variable: character_set_server T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T}
T{ Rpl_status T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ safe-mode T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T}
T{ safe-show-database T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: safe_show_database T}:T{ T}:T{
T}:T{ Y T}:T{ T}:T{ T} T{ safe-user-create T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
safemalloc-mem-limit T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ secure-auth T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ - Variable: secure_auth T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ Select_full_join T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Select_full_range_join T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
character-sets-dir T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Select_range T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ Select_range_check T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Select_scan T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ server-id T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: server_id T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ set-variable T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
show-slave-auth-info T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ skip-automatic-sp-privileges T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T}:T{ T} T{ skip-bdb T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: have_bdb T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ character_set_client T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
skip-character-set-client-handshake T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ skip-external-locking T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: external-locking T}:T{ T}:T{ T}:T{ T}:T{ T}:T{ T} T{
skip-grant-tables T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ skip-host-cache T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ skip-innodb T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ skip-innodb-checksums T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T}:T{ T} T{ skip-innodb-doublewrite T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable:
innodb_doublewrite T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ skip-large-pages T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ character_set_connection T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ - Variable: large-pages
T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ skip-locking T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{
skip-merge T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: merge T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{
T} T{ skip-name-resolve T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ skip-networking T}:T{ Y T}:T{ Y T}:T{
T}:T{ T}:T{ T} T{ skip-new T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ skip-show-database T}:T{ Y T}:T{ Y
T}:T{ T}:T{ T}:T{ T} T{ skip-slave-start T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ skip-stack-trace
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ character_set_results T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
skip-symbolic-links T}:T{ Y T}:T{ T}:T{ T}:T{ T}:T{ T} T{ skip-symlink T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ skip-sync-bdb-logs T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ skip-thread-priority T}:T{ Y T}:T{
Y T}:T{ T}:T{ T}:T{ T} T{ slave-load-tmpdir T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ slave-skip-errors
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ slave_compressed_protocol T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ slave_net_timeout T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Slave_open_temp_tables T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Slave_retried_transactions T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ chroot
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ Slave_running T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
slave_transaction_retries T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Slow_launch_threads T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ slow_launch_time T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Slow_queries T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ socket T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ sort_buffer_size T}:T{ Y
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Sort_merge_passes T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Sort_range
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Sort_rows T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ ansi T}:T{
Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ collation-server T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ Sort_scan
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ sporadic-binlog-dump-fail T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ sql-bin-update-same T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ sql-mode T}:T{ Y T}:T{ Y T}:T{ T}:T{
T}:T{ T} T{ - Variable: sql_mode T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_auto_is_null T}:T{ T}:T{
T}:T{ Y T}:T{ T}:T{ T} T{ sql_big_selects T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_big_tables T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_buffer_result T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
sql_log_bin T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ - Variable: collation_server T}:T{ T}:T{ T}:T{ Y
T}:T{ T}:T{ T} T{ sql_log_off T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_log_update T}:T{ T}:T{
T}:T{ Y T}:T{ T}:T{ T} T{ sql_low_priority_updates T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
sql_max_join_size T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_notes T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{
T} T{ sql_quote_show_create T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_safe_updates T}:T{ T}:T{ T}:T{
Y T}:T{ T}:T{ T} T{ sql_select_limit T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_slave_skip_counter
T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sql_warnings T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
Com_admin_commands T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ ssl T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}
T{ ssl-ca T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ ssl-capath T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
ssl-cert T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ ssl-cipher T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
ssl-key T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ storage_engine T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T}
T{ symbolic-links T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ sync-bdb-logs T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ sync-binlog T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ Com_alter_db T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ - Variable: sync_binlog T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ sync-frm T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ - Variable: sync_frm T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
sysdate-is-now T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ table_cache T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{
T} T{ table_lock_wait_timeout T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Table_locks_immediate T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Table_locks_waited T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ table_open_cache
T}:T{ T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ table_type T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
Com_alter_event T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ tc-heuristic-recover T}:T{ Y T}:T{ T}:T{ Y T}:T{
T}:T{ T} T{ Tc_log_max_pages_used T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Tc_log_page_size T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Tc_log_page_waits T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ temp-pool
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ thread_cache_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{
thread_concurrency T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ thread_stack T}:T{ Y T}:T{ Y T}:T{ Y T}:T{
T}:T{ T} T{ Threads_cached T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Threads_connected T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_alter_table T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Threads_created T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Threads_running T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ time_format
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ time_zone T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{
timed_mutexes T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ timestamp T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T}
T{ tmp_table_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ tmpdir T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}
T{ transaction-isolation T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ transaction_alloc_block_size T}:T{ Y T}:T{
Y T}:T{ Y T}:T{ T}:T{ T} T{ Com_analyze T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
transaction_prealloc_size T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ tx_isolation T}:T{ T}:T{ T}:T{ Y
T}:T{ T}:T{ T} T{ unique_checks T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ updatable_views_with_limit
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Uptime T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ user T}:T{ Y
T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ verbose T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ version T}:T{ Y T}:T{
T}:T{ T}:T{ T}:T{ T} T{ wait_timeout T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ warning_count T}:T{
T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ Com_backup_table T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ warnings
T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ with-debug T}:T{ Y T}:T{ Y T}:T{ T}:T{ T}:T{ T} T{ Com_begin
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_change_db T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
auto-increment-increment T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Com_change_master T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_check T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_checksum T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_commit T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_create_db T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_create_event T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_create_function
T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_create_index T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_create_table T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_dealloc_sql T}:T{ T}:T{ T}:T{ T}:T{ Y
T}:T{ T} T{ auto-increment-offset T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Com_delete T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_delete_multi T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_do T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_drop_db T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_drop_event T}:T{
T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_drop_function T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_drop_index T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_drop_table T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{
T} T{ Com_drop_user T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_execute_sql T}:T{ T}:T{ T}:T{ T}:T{
Y T}:T{ T} T{ autocommit T}:T{ T}:T{ T}:T{ Y T}:T{ T}:T{ T} T{ Com_flush T}:T{ T}:T{ T}:T{ T}:T{
Y T}:T{ T} T{ Com_grant T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_ha_close T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_ha_open T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_ha_read T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_help T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_insert T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_insert_select T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_kill T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_load T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ automatic-sp-privileges
T}:T{ Y T}:T{ Y T}:T{ Y T}:T{ T}:T{ T} T{ Com_load_master_data T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_load_master_table T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_lock_tables T}:T{ T}:T{ T}:T{ T}:T{
Y T}:T{ T} T{ Com_optimize T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_preload_keys T}:T{ T}:T{ T}:T{
T}:T{ Y T}:T{ T} T{ Com_prepare_sql T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_purge T}:T{ T}:T{
T}:T{ T}:T{ Y T}:T{ T} T{ Com_purge_before_date T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{
Com_rename_table T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{ T} T{ Com_repair T}:T{ T}:T{ T}:T{ T}:T{ Y T}:T{
T}
COMMAND OPTIONS
When you start the mysqld server, you can specify program options using any of the methods described in
Section 3, "Specifying Program Options". The most common methods are to provide options in an option file or on
the command line. However, in most cases it is desirable to make sure that the server uses the same options each
time it runs. The best way to ensure this is to list them in an option file. See Section 3.2, "Using Option
Files".
mysqld reads options from the [mysqld] and [server] groups. mysqld_safe reads options from the [mysqld],
[server], [mysqld_safe], and [safe_mysqld] groups. mysql.server reads options from the [mysqld] and
[mysql.server] groups.
An embedded MySQL server usually reads options from the [server], [embedded], and [xxxxx_SERVER] groups, where
xxxxx is the name of the application into which the server is embedded.
mysqld accepts many command options. For a brief summary, execute mysqld --help. To see the full list, use mysqld
--verbose --help.
The following list shows some of the most common server options. Additional options are described in other
sections:
� Options that affect security: See Section 5.3, "Security-Related mysqld Options".
� SSL-related options: See Section 7.7.3, "SSL Command Options".
� Binary log control options: See Section 10.3, "The Binary Log".
� Replication-related options: See Section 8, "Replication Startup Options".
� Options specific to particular storage engines: See Section 1.1, "MyISAM Startup Options", Section 5.3, "BDB
Startup Options", Section 2.4, "InnoDB Startup Options and System Variables", and Section 6.5.1, "MySQL
Cluster-Related Command Options for mysqld".
You can also set the values of server system variables by using variable names as options, as described later in this section.
� --help, -?
Display a short help message and exit. Use both the --verbose and --help options to see the full message.
� --allow-suspicious-udfs
This option controls whether user-defined functions that have only an xxx symbol for the main function can be loaded. By default, the option is off and only UDFs that have at least one auxiliary symbol can be loaded; this prevents attempts at loading functions from shared object files other than those containing legitimate UDFs. This option was added in version 5.0.3. See Section 2.4.6, "User-Defined Function Security Precautions".
� --ansi
Use standard (ANSI) SQL syntax instead of MySQL syntax. For more precise control over the server SQL mode, use the --sql-mode option instead. See Section 9.3, "Running MySQL in ANSI Mode", and the section called "SQL MODES".
� --basedir=path, -b path
The path to the MySQL installation directory. All paths are usually resolved relative to this directory.
� big-tables
Allow large result sets by saving all temporary sets in files. This option prevents most "table full" errors, but also slows down queries for which in-memory tables would suffice. Since MySQL 3.23.2, the server is able to handle large result sets automatically by using memory for small temporary tables and switching to disk tables where necessary.
� --bind-address=IP
The IP address to bind to.
� --bootstrap
This option is used by the mysql_install_db script to create the MySQL privilege tables without having to start a full MySQL server.
� --character-sets-dir=path
The directory where character sets are installed. See Section 9.1, "The Character Set Used for Data and Sorting".
� --character-set-client-handshake
Don't ignore character set information sent by the client. To ignore client information and use the default server character set, use --skip-character-set-client-handshake; this makes MySQL behave like MySQL 4.0.
� --character-set-filesystem=charset_name
The filesystem character set. This option sets the character_set_filesystem system variable. It was added in MySQL 5.0.19.
� --character-set-server=charset_name, -C charset_name
Use charset_name as the default server character set. See Section 9.1, "The Character Set Used for Data and Sorting". If you use this option to specify a non-default character set, you should also use --collation-server to specify the collation.
� --chroot=path
Put the mysqld server in a closed environment during startup by using the chroot() system call. This is a recommended security measure. Note that use of this option somewhat limits LOAD DATA INFILE and SELECT ... INTO OUTFILE.
� --collation-server=collation_name
Use collation_name as the default server collation. See Section 9.1, "The Character Set Used for Data and Sorting".
� --console
(Windows only.) Write error log messages to stderr and stdout even if --log-error is specified. mysqld does not close the console window if this option is used.
� --core-file
Write a core file if mysqld dies. For some systems, you must also specify the --core-file-size option to mysqld_safe. See mysqld_safe(1). Note that on some systems, such as Solaris, you do not get a core file if you are also using the --user option.
� --datadir=path, -h path
The path to the data directory.
� --debug[=debug_options], -# [debug_options]
If MySQL is configured with --with-debug, you can use this option to get a trace file of what mysqld is doing. The debug_options string often is �d:t:o,file_name'. The default is �d:t:i:o,mysqld.trace'. See Section 1.2, "Creating Trace Files".
� --default-character-set=charset_name (DEPRECATED)
Use charset_name as the default character set. This option is deprecated in favor of --character-set-server. See Section 9.1, "The Character Set Used for Data and Sorting".
� --default-collation=collation_name
Use collation_name as the default collation. This option is deprecated in favor of --collation-server. See Section 9.1, "The Character Set Used for Data and Sorting".
� --default-storage-engine=type
Set the default storage engine (table type) for tables. See Chapter 14, Storage Engines and Table Types.
� --default-table-type=type
This option is a synonym for --default-storage-engine.
� --default-time-zone=timezone
Set the default server time zone. This option sets the global time_zone system variable. If this option is not given, the default time zone is the same as the system time zone (given by the value of the system_time_zone system variable.
� --delay-key-write[={OFF|ON|ALL}]
Specify how to use delayed key writes. Delayed key writing causes key buffers not to be flushed between writes for MyISAM tables. OFF disables delayed key writes. ON enables delayed key writes for those tables that were created with the DELAY_KEY_WRITE option. ALL delays key writes for all MyISAM tables. See Section 5.2, "Tuning Server Parameters", and Section 1.1, "MyISAM Startup Options". Note: If you set this variable to ALL, you should not use MyISAM tables from within another program (such as another MySQL server or myisamchk) when the tables are in use. Doing so leads to index corruption.
� --des-key-file=file_name
Read the default DES keys from this file. These keys are used by the DES_ENCRYPT() and DES_DECRYPT() functions.
� --enable-named-pipe
Enable support for named pipes. This option applies only on Windows NT, 2000, XP, and 2003 systems, and can be used only with the mysqld-nt and mysqld-max-nt servers that support named-pipe connections.
� --exit-info[=flags], -T [flags]
This is a bit mask of different flags that you can use for debugging the mysqld server. Do not use this option unless you know exactly what it does!
� --external-locking
Enable external locking (system locking), which is disabled by default as of MySQL 4.0. Note that if you use this option on a system on which lockd does not fully work (such as Linux), it is easy for mysqld to deadlock. This option previously was named --enable-locking. Note: If you use this option to enable updates to MyISAM tables from many MySQL processes, you must ensure that the following conditions are satisfied: � You should not use the query cache for queries that use tables that are updated by another process. � You should not use --delay-key-write=ALL or DELAY_KEY_WRITE=1 on any shared tables. The easiest way to ensure this is to always use --external-locking together with --delay-key-write=OFF and --query-cache-size=0. (This is not done by default because in many setups it is useful to have a mixture of the preceding options.)
� --flush
Flush (synchronize) all changes to disk after each SQL statement. Normally, MySQL does a write of all changes to disk only after each SQL statement and lets the operating system handle the synchronizing to disk. See Section 4.2, "What to Do If MySQL Keeps Crashing".
� --init-file=file_name
Read SQL statements from this file at startup. Each statement must be on a single line and should not include comments.
� --innodb-safe-binlog
Adds consistency guarantees between the content of InnoDB tables and the binary log. See Section 10.3, "The Binary Log". This option was removed in MySQL 5.0.3, having been made obsolete by the introduction of XA transaction support.
� --innodb-xxx
The InnoDB options are listed in Section 2.4, "InnoDB Startup Options and System Variables".
� --language=lang_name, -L lang_name
Return client error messages in the given language. lang_name can be given as the language name or as the full pathname to the directory where the language files are installed. See Section 9.2, "Setting the Error Message Language".
� --large-pages
Some hardware/operating system architectures support memory pages greater than the default (usually 4KB). The actual implementation of this support depends on the underlying hardware and OS. Applications that perform a lot of memory accesses may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses. Currently, MySQL supports only the Linux implementation of large pages support (which is called HugeTLB in Linux). We have plans to extend this support to FreeBSD, Solaris and possibly other platforms. Before large pages can be used on Linux, it is necessary to configure the HugeTLB memory pool. For reference, consult the hugetlbpage.txt file in the Linux kernel source. This option is disabled by default. It was added in MySQL 5.0.3.
� --log[=file_name], -l [file_name]
Log connections and SQL statements received from clients to this file. See Section 10.2, "The General Query Log". If you omit the filename, MySQL uses host_name.log as the filename.
� --log-bin[=base_name]
Enable binary logging. The server logs all statements that change data to the binary log, which is used for backup and replication. See Section 10.3, "The Binary Log". The option value, if given, is the basename for the log sequence. The server creates binary log files in sequence by adding a numeric suffix to the basename. It is recommended that you specify a basename (see Section 8.1, "Open Issues in MySQL", for the reason). Otherwise, MySQL uses host_name-bin as the basename.
� --log-bin-index[=file_name]
The index file for binary log filenames. See Section 10.3, "The Binary Log". If you omit the filename, and if you didn't specify one with --log-bin, MySQL uses host_name-bin.index as the filename.
� --log-bin-trust-function-creators[={0|1}]
With no argument or an argument of 1, this option sets the log_bin_trust_function_creators system variable to 1. With an argument of 0, this option sets the system variable to 0. log_bin_trust_function_creators affects how MySQL enforces restrictions on stored function creation. See Section 5, "Binary Logging of Stored Routines and Triggers". This option was added in MySQL 5.0.16.
� --log-bin-trust-routine-creators[={0|1}]
This is the old name for --log-bin-trust-function-creators. Before MySQL 5.0.16, it also applies to stored procedures, not just stored functions and sets the log_bin_trust_routine_creators system variable. As of 5.0.16, this option is deprecated. It is recognized for backward compatibility but its use results in a warning. This option was added in MySQL 5.0.6.
� --log-error[=file_name]
Log errors and startup messages to this file. See Section 10.1, "The Error Log". If you omit the filename, MySQL uses host_name.err. If the filename has no extension, the server adds an extension of .err.
� --log-isam[=file_name]
Log all MyISAM changes to this file (used only when debugging MyISAM).
� --log-long-format (DEPRECATED)
Log extra information to the update log, binary update log, and slow query log, if they have been activated. For example, the username and timestamp are logged for all queries. This option is deprecated, as it now represents the default logging behavior. (See the description for --log-short-format.) The --log-queries-not-using-indexes option is available for the purpose of logging queries that do not use indexes to the slow query log.
� --log-queries-not-using-indexes
If you are using this option with --log-slow-queries, queries that do not use indexes are logged to the slow query log. See Section 10.4, "The Slow Query Log".
� --log-short-format
Log less information to the update log, binary update log, and slow query log, if they have been activated. For example, the username and timestamp are not logged for queries.
� --log-slow-admin-statements
Log slow administrative statements such as OPTIMIZE TABLE, ANALYZE TABLE, and ALTER TABLE to the slow query log.
� --log-slow-queries[=file_name]
Log all queries that have taken more than long_query_time seconds to execute to this file. See Section 10.4, "The Slow Query Log". See the descriptions of the --log-long-format and --log-short-format options for details.
� --log-tc=file_name
The name of the memory-mapped transaction coordinator log file (for XA transactions that affect multiple storage engines when the binary log is disabled). The default name is tc.log. The file is created under the data directory if not given as a full pathname. Currently, this option is unused. Added in MySQL 5.0.3.
� --log-tc-size=size
The size in bytes of the memory-mapped transaction coordinator log. The default size is 24KB. Added in MySQL 5.0.3.
� --log-warnings[=level], -W [level]
Print out warnings such as Aborted connection... to the error log. Enabling this option is recommended, for example, if you use replication (you get more information about what is happening, such as messages about network failures and reconnections). This option is enabled(1) by default, and the default level value if omitted is 1. To disable this option, use --log-warnings=0. Aborted connections are not logged to the error log unless the value is greater than 1. See Section 2.10, "Communication Errors and Aborted Connections".
� --low-priority-updates
Give table-modifying operations (INSERT, REPLACE, DELETE, UPDATE) lower priority than selects. This can also be done
via {INSERT | REPLACE | DELETE | UPDATE} LOW_PRIORITY ... to lower the priority of only one query, or by SET
LOW_PRIORITY_UPDATES=1 to change the priority in one thread. See Section 3.2, "Table Locking Issues".
� --memlock
Lock the mysqld process in memory. This works on systems such as Solaris that support the mlockall() system call. This might help if you have a problem where the operating system is causing mysqld to swap on disk. Note that use of this option requires that you run the server as root, which is normally not a good idea for security reasons. See Section 5.5, "How to Run MySQL as a Normal User".
� --myisam-recover[=option[,option]...]]
Set the MyISAM storage engine recovery mode. The option value is any combination of the values of DEFAULT, BACKUP,
FORCE, or QUICK. If you specify multiple values, separate them by commas. You can also use a value of "" to disable
this option. If this option is used, each time mysqld opens a MyISAM table, it checks whether the table is marked as
crashed or wasn't closed properly. (The last option works only if you are running with external locking disabled.) If
this is the case, mysqld runs a check on the table. If the table was corrupted, mysqld attempts to repair it.
The following options affect how the repair works:
allbox tab(:); l l l l l l l l l l. T{ Option T}:T{ Description T} T{ DEFAULT T}:T{ The same as not giving any
option to --myisam-recover. T} T{ BACKUP T}:T{ If the data file was changed during recovery, save a backup of the
tbl_name.MYD
file as
tbl_name-datetime.BAK. T} T{ FORCE T}:T{ Run recovery even if we would lose more than one row
from the
.MYD file. T} T{ QUICK T}:T{ Don't check the rows in the table if there aren't any delete
blocks. T}
Before the server automatically repairs a table, it writes a note about the repair to the error log. If you want to
be able to recover from most problems without user intervention, you should use the options BACKUP,FORCE. This forces
a repair of a table even if some rows would be deleted, but it keeps the old data file as a backup so that you can
later examine what happened.
See Section 1.1, "MyISAM Startup Options".
� --ndb-connectstring=connect_string
When using the NDB storage engine, it is possible to point out the management server that distributes the cluster configuration by setting the connect string option. See Section 4.4.2, "The Cluster connectstring", for syntax.
� --ndbcluster
If the binary includes support for the NDB Cluster storage engine, this option enables the engine, which is disabled by default. See Chapter 15, MySQL Cluster.
� --old-passwords
Force the server to generate short (pre-4.1) password hashes for new passwords. This is useful for compatibility when the server must support older client programs. See Section 6.9, "Password Hashing as of MySQL 4.1".
� --one-thread
Only use one thread (for debugging under Linux). This option is available only if the server is built with debugging enabled. See Section 1, "Debugging a MySQL Server".
� --open-files-limit=count
Change the number of file descriptors available to mysqld. If this option is not set or is set to 0, mysqld uses the value to reserve file descriptors with setrlimit(). If the value is 0, mysqld reserves max_connections�5 or max_connections + table_open_cache�2 files (whichever is larger). You should try increasing this value if mysqld gives you the error Too many open files.
� --pid-file=path
The pathname of the process ID file. This file is used by other programs such as mysqld_safe to determine the server's process ID.
� --port=port_num, -P port_num
The port number to use when listening for TCP/IP connections. The port number must be 1024 or higher unless the server is started by the root system user.
� --port-open-timeout=num
On some systems, when the server is stopped, the TCP/IP port might not become available immediately. If the server is restarted quickly afterward, its attempt to reopen the port can fail. This option indicates how many seconds the server should wait for the TCP/IP port to become free if it cannot be opened. The default is not to wait. This option was added in MySQL 5.0.19.
� --safe-mode
Skip some optimization stages.
� --safe-show-database (DEPRECATED)
See Section 6.3, "Privileges Provided by MySQL".
� --safe-user-create
If this option is enabled, a user cannot create new MySQL users by using the GRANT statement, if the user doesn't have the INSERT privilege for the mysql.user table or any column in the table.
� --secure-auth
Disallow authentication by clients that attempt to use accounts that have old (pre-4.1) passwords.
� --shared-memory
Enable shared-memory connections by local clients. This option is available only on Windows.
� --shared-memory-base-name=name
The name of shared memory to use for shared-memory connections. This option is available only on Windows. The default name is MYSQL. The name is case sensitive.
� --skip-bdb
Disable the BDB storage engine. This saves memory and might speed up some operations. Do not use this option if you require BDB tables.
� --skip-concurrent-insert
Turn off the ability to select and insert at the same time on MyISAM tables. (This is to be used only if you think you have found a bug in this feature.) See Section 3.3, "Concurrent Inserts".
� --skip-external-locking
Do not use external locking (system locking). With external locking disabled, you must shut down the server to use myisamchk. (See Section 4.3, "MySQL Stability".) To avoid this requirement, use the CHECK TABLE and REPAIR TABLE statements to check and repair MyISAM tables. External locking has been disabled by default since MySQL 4.0.
� --skip-grant-tables
This option causes the server not to use the privilege system at all, which gives anyone with access to the server unrestricted access to all databases. You can cause a running server to start using the grant tables again by executing mysqladmin flush-privileges or mysqladmin reload command from a system shell, or by issuing a MySQL FLUSH PRIVILEGES statement after connecting to the server. This option also suppresses loading of user-defined functions (UDFs).
� --skip-host-cache
Do not use the internal hostname cache for faster name-to-IP resolution. Instead, query the DNS server every time a client connects. See Section 5.6, "How MySQL Uses DNS".
� --skip-innodb
Disable the InnoDB storage engine. This saves memory and disk space and might speed up some operations. Do not use this option if you require InnoDB tables.
� --skip-merge
Disable the MERGE storage engine. This option was added in MySQL 5.0.24. It can be used if the following behavior is undesirable: If a user has access to MyISAM table t, that user can create a MERGE table m that accesses t. However, if the user's privileges on t are subsequently revoked, the user can continue to access t by doing so through m.
� --skip-name-resolve
Do not resolve hostnames when checking client connections. Use only IP numbers. If you use this option, all Host column values in the grant tables must be IP numbers or localhost. See Section 5.6, "How MySQL Uses DNS".
� --skip-ndbcluster
Disable the NDB Cluster storage engine. This is the default for binaries that were built with NDB Cluster storage engine support; the server allocates memory and other resources for this storage engine only if the --ndbcluster option is given explicitly. See Section 4.3, "Quick Test Setup of MySQL Cluster", for an example of usage.
� --skip-networking
Don't listen for TCP/IP connections at all. All interaction with mysqld must be made via named pipes or shared memory (on Windows) or Unix socket files (on Unix). This option is highly recommended for systems where only local clients are allowed. See Section 5.6, "How MySQL Uses DNS".
� --ssl*
Options that begin with --ssl specify whether to allow clients to connect via SSL and indicate where to find SSL keys and certificates. See Section 7.7.3, "SSL Command Options".
� --standalone
Available on Windows NT-based systems only; instructs the MySQL server not to run as a service.
� --symbolic-links, --skip-symbolic-links
Enable or disable symbolic link support. This option has different effects on Windows and Unix:
� On Windows, enabling symbolic links allows you to establish a symbolic link to a database directory by creating a
db_name.sym file that contains the path to the real directory. See Section 6.1.3, "Using Symbolic Links for
Databases on Windows".
� On Unix, enabling symbolic links means that you can link a MyISAM index file or data file to another directory
with the INDEX DIRECTORY or DATA DIRECTORY options of the CREATE TABLE statement. If you delete or rename the
table, the files that its symbolic links point to also are deleted or renamed. See Section 6.1.2, "Using Symbolic
Links for Tables on Unix".
� --skip-safemalloc
If MySQL is configured with --with-debug=full, all MySQL programs check for memory overruns during each memory allocation and memory freeing operation. This checking is very slow, so for the server you can avoid it when you don't need it by using the --skip-safemalloc option.
� --skip-show-database
With this option, the SHOW DATABASES statement is allowed only to users who have the SHOW DATABASES privilege, and the statement displays all database names. Without this option, SHOW DATABASES is allowed to all users, but displays each database name only if the user has the SHOW DATABASES privilege or some privilege for the database. Note that any global privilege is considered a privilege for the database.
� --skip-stack-trace
Don't write stack traces. This option is useful when you are running mysqld under a debugger. On some systems, you also must use this option to get a core file. See Section 1, "Debugging a MySQL Server".
� --skip-thread-priority
Disable using thread priorities for faster response time.
� --socket=path
On Unix, this option specifies the Unix socket file to use when listening for local connections. The default value is /tmp/mysql.sock. On Windows, the option specifies the pipe name to use when listening for local connections that use a named pipe. The default value is MySQL (not case sensitive).
� --sql-mode=value[,value[,value...]]
Set the SQL mode. See the section called "SQL MODES".
� --sysdate-is-now
As of MySQL 5.0.13, SYSDATE() by default returns the time at which it executes, not the time at which the statement in which it occurs begins executing. This differs from the behavior of NOW(). This option causes SYSDATE() to be an alias for NOW(). For information about the implications for binary logging and replication, see the description for SYSDATE() in Section 5, "Date and Time Functions" and for SET TIMESTAMP in Section 5.3, "SET Syntax". This option was added in MySQL 5.0.20.
� --tc-heuristic-recover={COMMIT|ROLLBACK}
The type of decision to use in the heuristic recovery process. Currently, this option is unused. Added in MySQL 5.0.3.
� --temp-pool
This option causes most temporary files created by the server to use a small set of names, rather than a unique name for each new file. This works around a problem in the Linux kernel dealing with creating many new files with different names. With the old behavior, Linux seems to "leak" memory, because it is being allocated to the directory entry cache rather than to the disk cache.
� --transaction-isolation=level
Sets the default transaction isolation level. The level value can be READ-UNCOMMITTED, READ-COMMITTED, REPEATABLE-READ, or SERIALIZABLE. See Section 4.6, "SET TRANSACTION Syntax".
� --tmpdir=path, -t path
The path of the directory to use for creating temporary files. It might be useful if your default /tmp directory resides on a partition that is too small to hold temporary tables. This option accepts several paths that are used in round-robin fashion. Paths should be separated by colon characters (`:') on Unix and semicolon characters (`;') on Windows, NetWare, and OS/2. If the MySQL server is acting as a replication slave, you should not set --tmpdir to point to a directory on a memory-based filesystem or to a directory that is cleared when the server host restarts. For more information about the storage location of temporary files, see Section 4.4, "Where MySQL Stores Temporary Files". A replication slave needs some of its temporary files to survive a machine restart so that it can replicate temporary tables or LOAD DATA INFILE operations. If files in the temporary file directory are lost when the server restarts, replication fails.
� --user={user_name|user_id}, -u {user_name|user_id}
Run the mysqld server as the user having the name user_name or the numeric user ID user_id. ("User" in this context
refers to a system login account, not a MySQL user listed in the grant tables.)
This option is mandatory when starting mysqld as root. The server changes its user ID during its startup sequence,
causing it to run as that particular user rather than as root. See Section 5.1, "General Security Guidelines".
To avoid a possible security hole where a user adds a --user=root option to a my.cnf file (thus causing the server to
run as root), mysqld uses only the first --user option specified and produces a warning if there are multiple --user
options. Options in /etc/my.cnf and $MYSQL_HOME/my.cnf are processed before command-line options, so it is
recommended that you put a --user option in /etc/my.cnf and specify a value other than root. The option in
/etc/my.cnf is found before any other --user options, which ensures that the server runs as a user other than root,
and that a warning results if any other --user option is found.
� --version, -V
Display version information and exit.
You can assign a value to a server system variable by using an option of the form --var_name=value. For example, --key_buffer_size=32M sets the key_buffer_size variable to a value of 32MB.
Note that when you assign a value to a variable, MySQL might automatically correct the value to stay within a given range, or adjust the value to the closest allowable value if only certain values are allowed.
If you want to restrict the maximum value to which a variable can be set at runtime with SET, you can define this by using the --maximum-var_name=value command-line option.
It is also possible to set variables by using --set-variable=var_name=value or -O var_name=value syntax. This syntax is deprecated.
You can change the values of most system variables for a running server with the SET statement. See Section 5.3, "SET Syntax".
the section called "SYSTEM VARIABLES", provides a full description for all variables, and additional information for setting them at server startup and runtime. Section 5.2, "Tuning Server Parameters", includes information on optimizing the server by tuning system variables.
SYSTEM VARIABLES
The mysql server maintains many system variables that indicate how it is configured. Each system variable has a
default value. System variables can be set at server startup using options on the command line or in an option
file. Most of them can be changed dynamically while the server is running by means of the SET statement, which
enables you to modify operation of the server without having to stop and restart it. You can refer to system
variable values in expressions.
There are several ways to see the names and values of system variables:
� To see the values that a server will use based on its compiled-in defaults and any option files that it reads,
use this command:
mysqld --verbose --help
� To see the values that a server will use based on its compiled-in defaults, ignoring the settings in any
option files, use this command:
mysqld --no-defaults --verbose --help
� To see the current values used by a running server, use the SHOW VARIABLES statement.
This section provides a description of each system variable. Variables with no version indicated are present in
all MySQL 5.0 releases. For historical information concerning their implementation, please see MySQL 3.23, 4.0,
4.1 Reference Manual.
For additional system variable information, see these sections:
� the section called "USING SYSTEM VARIABLES", discusses the syntax for setting and displaying system variable
values.
� the section called "Dynamic System Variables", lists the variables that can be set at runtime.
� Information on tuning sytem variables can be found in Section 5.2, "Tuning Server Parameters".
� Section 2.4, "InnoDB Startup Options and System Variables", lists InnoDB system variables.
Note: Some of the following variable descriptions refer to "enabling" or "disabling" a variable. These variables
can be enabled with the SET statement by setting them to ON or 1, or disabled by setting them to OFF or 0.
However, to set such a variable on the command line or in an option file, you must set it to 1 or 0; setting it
to ON or OFF will not work. For example, on the command line, --delay_key_write=1 works but --delay_key_write=ON
does not.
Values for buffer sizes, lengths, and stack sizes are given in bytes unless otherwise specified.
� auto_increment_increment
auto_increment_increment and auto_increment_offset are intended for use with master-to-master replication, and
can be used to control the operation of AUTO_INCREMENT columns. Both variables can be set globally or locally,
and each can assume an integer value between 1 and 65,535 inclusive. Setting the value of either of these two
variables to 0 causes its value to be set to 1 instead. Attempting to set the value of either of these two
variables to an integer greater than 65,535 or less than 0 causes its value to be set to 65,535 instead.
Attempting to set the value of auto_increment_increment or auto_increment_offset to a non-integer value gives
rise to an error, and the actual value of the variable remains unchanged.
These two variables affect AUTO_INCREMENT column behavior as follows:
� auto_increment_increment controls the interval between successive column values. For example:
mysql> SHOW VARIABLES LIKE 'auto_inc%';
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| auto_increment_increment | 1 |
| auto_increment_offset | 1 |
+--------------------------+-------+
2 rows in set (0.00 sec)
mysql> CREATE TABLE autoinc1
-> (col INT NOT NULL AUTO_INCREMENT PRIMARY KEY);
Query OK, 0 rows affected (0.04 sec)
mysql> SET @@auto_increment_increment=10;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE 'auto_inc%';
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| auto_increment_increment | 10 |
| auto_increment_offset | 1 |
+--------------------------+-------+
2 rows in set (0.01 sec)
mysql> INSERT INTO autoinc1 VALUES (NULL), (NULL), (NULL), (NULL);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql> SELECT col FROM autoinc1;
+-----+
| col |
+-----+
| 1 |
| 11 |
| 21 |
| 31 |
+-----+
4 rows in set (0.00 sec)
(Note how SHOW VARIABLES is used here to obtain the current values for these variables.)
� auto_increment_offset determines the starting point for the AUTO_INCREMENT column value. Consider the
following, assuming that these statements are executed during the same session as the example given in the
description for auto_increment_increment:
mysql> SET @@auto_increment_offset=5;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE 'auto_inc%';
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| auto_increment_increment | 10 |
| auto_increment_offset | 5 |
+--------------------------+-------+
2 rows in set (0.00 sec)
mysql> CREATE TABLE autoinc2
-> (col INT NOT NULL AUTO_INCREMENT PRIMARY KEY);
Query OK, 0 rows affected (0.06 sec)
mysql> INSERT INTO autoinc2 VALUES (NULL), (NULL), (NULL), (NULL);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql> SELECT col FROM autoinc2;
+-----+
| col |
+-----+
| 5 |
| 15 |
| 25 |
| 35 |
+-----+
4 rows in set (0.02 sec)
If the value of auto_increment_offset is greater than that of auto_increment_increment, the value of
auto_increment_offset is ignored.
Should one or both of these variables be changed and then new rows inserted into a table containing an
AUTO_INCREMENT column, the results may seem counterintuitive because the series of AUTO_INCREMENT values is
calculated without regard to any values already present in the column, and the next value inserted is the
least value in the series that is greater than the maximum existing value in the AUTO_INCREMENT column. In
other words, the series is calculated like so:
auto_increment_offset + N � auto_increment_increment
where N is a positive integer value in the series [1, 2, 3, ...]. For example:
mysql> SHOW VARIABLES LIKE 'auto_inc%';
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| auto_increment_increment | 10 |
| auto_increment_offset | 5 |
+--------------------------+-------+
2 rows in set (0.00 sec)
mysql> SELECT col FROM autoinc1;
+-----+
| col |
+-----+
| 1 |
| 11 |
| 21 |
| 31 |
+-----+
4 rows in set (0.00 sec)
mysql> INSERT INTO autoinc1 VALUES (NULL), (NULL), (NULL), (NULL);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql> SELECT col FROM autoinc1;
+-----+
| col |
+-----+
| 1 |
| 11 |
| 21 |
| 31 |
| 35 |
| 45 |
| 55 |
| 65 |
+-----+
8 rows in set (0.00 sec)
The values shown for auto_increment_increment and auto_increment_offset generate the series 5 + N � 10, that is,
[5, 15, 25, 35, 45, ...]. The greatest value present in the col column prior to the INSERT is 31, and the next
available value in the AUTO_INCREMENT series is 35, so the inserted values for col begin at that point and the
results are as shown for the SELECT query.
It is important to remember that it is not possible to confine the effects of these two variables to a single
table, and thus they do not take the place of the sequences offered by some other database management systems;
these variables control the behavior of all AUTO_INCREMENT columns in all tables on the MySQL server. If one of
these variables is set globally, its effects persist until the global value is changed or overridden by setting
them locally, or until mysqld is restarted. If set locally, the new value affects AUTO_INCREMENT columns for all
tables into which new rows are inserted by the current user for the duration of the session, unless the values
are changed during that session.
The auto_increment_increment variable was added in MySQL 5.0.2. Its default value is 1. See Section 13,
"Auto-Increment in Multiple-Master Replication".
� > auto_increment_offset
This variable was introduced in MySQL 5.0.2. Its default value is 1. For particulars, see the description for
auto_increment_increment.
� back_log
The number of outstanding connection requests MySQL can have. This comes into play when the main MySQL thread
gets very many connection requests in a very short time. It then takes some time (although very little) for
the main thread to check the connection and start a new thread. The back_log value indicates how many requests
can be stacked during this short time before MySQL momentarily stops answering new requests. You need to
increase this only if you expect a large number of connections in a short period of time.
In other words, this value is the size of the listen queue for incoming TCP/IP connections. Your operating
system has its own limit on the size of this queue. The manual page for the Unix listen() system call should
have more details. Check your OS documentation for the maximum value for this variable. back_log cannot be
set higher than your operating system limit.
� basedir
The MySQL installation base directory. This variable can be set with the --basedir option.
� bdb_cache_size
The size of the buffer that is allocated for caching indexes and rows for BDB tables. If you don't use BDB
tables, you should start mysqld with --skip-bdb to not allocate memory for this cache.
� bdb_home
The base directory for BDB tables. This should be assigned the same value as the datadir variable.
� bdb_log_buffer_size
The size of the buffer that is allocated for caching indexes and rows for BDB tables. If you don't use BDB
tables, you should set this to 0 or start mysqld with --skip-bdb to not allocate memory for this cache.
� bdb_logdir
The directory where the BDB storage engine writes its log files. This variable can be set with the
--bdb-logdir option.
� bdb_max_lock
The maximum number of locks that can be active for a BDB table (10,000 by default). You should increase this
value if errors such as the following occur when you perform long transactions or when mysqld has to examine
many rows to calculate a query:
bdb: Lock table is out of available locks
Got error 12 from ...
� bdb_shared_data
This is ON if you are using --bdb-shared-data to start Berkeley DB in multi-process mode. (Do not use
DB_PRIVATE when initializing Berkeley DB.)
� bdb_tmpdir
The BDB temporary file directory.
� binlog_cache_size
The size of the cache to hold the SQL statements for the binary log during a transaction. A binary log cache
is allocated for each client if the server supports any transactional storage engines and if the server has
the binary log enabled (--log-bin option). If you often use large, multiple-statement transactions, you can
increase this cache size to get more performance. The Binlog_cache_use and Binlog_cache_disk_use status
variables can be useful for tuning the size of this variable. See Section 10.3, "The Binary Log".
� bulk_insert_buffer_size
MyISAM uses a special tree-like cache to make bulk inserts faster for INSERT ... SELECT, INSERT ... VALUES
(...), (...), ..., and LOAD DATA INFILE when adding data to non-empty tables. This variable limits the size of
the cache tree in bytes per thread. Setting it to 0 disables this optimization. The default value is 8MB.
� character_set_client
The character set for statements that arrive from the client.
� character_set_connection
The character set used for literals that do not have a character set introducer and for number-to-string
conversion.
� character_set_database
The character set used by the default database. The server sets this variable whenever the default database
changes. If there is no default database, the variable has the same value as character_set_server.
� character_set_filesystem
The filesystem character set. This variable is used to interpret string literals that refer to filenames, such
as in the LOAD DATA INFILE and SELECT ... INTO OUTFILE statements and the LOAD_FILE() function. Such filenames
are converted from character_set_client to character_set_filesystem before the file opening attempt occurs.
The default value is binary, which means that no conversion occurs. For systems on which multi-byte filenames
are allowed, a different value may be more appropriate. For example, if the system represents filenames using
UTF-8, set character_set_filesytem to �utf8'. This variable was added in MySQL 5.0.19.
� character_set_results
The character set used for returning query results to the client.
� character_set_server
The server's default character set.
� character_set_system
The character set used by the server for storing identifiers. The value is always utf8.
� character_sets_dir
The directory where character sets are installed.
� collation_connection
The collation of the connection character set.
� collation_database
The collation used by the default database. The server sets this variable whenever the default database
changes. If there is no default database, the variable has the same value as collation_server.
� collation_server
The server's default collation.
� completion_type
The transaction completion type:
� If the value is 0 (the default), COMMIT and ROLLBACK are unaffected.
� If the value is 1, COMMIT and ROLLBACK are equivalent to COMMIT AND CHAIN and ROLLBACK AND CHAIN,
respectively. (A new transaction starts immediately with the same isolation level as the just-terminated
transaction.)
� If the value is 2, COMMIT and ROLLBACK are equivalent to COMMIT RELEASE and ROLLBACK RELEASE, respectively.
(The server disconnects after terminating the transaction.)
This variable was added in MySQL 5.0.3
� concurrent_insert
If ON (the default), MySQL allows INSERT and SELECT statements to run concurrently for MyISAM tables that have
no free blocks in the middle. You can turn this option off by starting mysqld with --safe or --skip-new.
In MySQL 5.0.6, this variable was changed to take three integer values:
allbox tab(:); l l l l l l l l. T{ Value T}:T{ Description T} T{ 0 T}:T{ Off T} T{ 1 T}:T{ (Default) Enables
concurrent insert for MyISAM tables
that don't have holes T} T{ 2 T}:T{ Enables concurrent inserts for all MyISAM tables. If
table has a hole and is in use by another thread
the new row will be inserted at end of table. If
table is not in use, MySQL does a normal read lock
and inserts the new row into the hole. T}
See also Section 3.3, "Concurrent Inserts".
� connect_timeout
The number of seconds that the mysqld server waits for a connect packet before responding with Bad handshake.
� datadir
The MySQL data directory. This variable can be set with the --datadir option.
� date_format
This variable is not implemented.
� datetime_format
This variable is not implemented.
� default_week_format
The default mode value to use for the WEEK() function. See Section 5, "Date and Time Functions".
� delay_key_write
This option applies only to MyISAM tables. It can have one of the following values to affect handling of the
DELAY_KEY_WRITE table option that can be used in CREATE TABLE statements.
allbox tab(:); l l l l l l l l. T{ Option T}:T{ Description T} T{ OFF T}:T{ DELAY_KEY_WRITE is ignored. T}
T{ ON T}:T{ MySQL honors any DELAY_KEY_WRITE option specified in
CREATE TABLE statements. This
is the default value. T} T{ ALL T}:T{ All new opened tables are treated as if they were
created with the
DELAY_KEY_WRITE option enabled. T}
If DELAY_KEY_WRITE is enabled for a table, the key buffer is not flushed for the table on every index update,
but only when the table is closed. This speeds up writes on keys a lot, but if you use this feature, you
should add automatic checking of all MyISAM tables by starting the server with the --myisam-recover option
(for example, --myisam-recover=BACKUP,FORCE). See the section called "COMMAND OPTIONS", and Section 1.1,
"MyISAM Startup Options".
Note that enabling external locking with --external-locking offers no protection against index corruption for
tables that use delayed key writes.
� delayed_insert_limit
After inserting delayed_insert_limit delayed rows, the INSERT DELAYED handler thread checks whether there are
any SELECT statements pending. If so, it allows them to execute before continuing to insert delayed rows.
� delayed_insert_timeout
How many seconds an INSERT DELAYED handler thread should wait for INSERT statements before terminating.
� delayed_queue_size
This is a per-table limit on the number of rows to queue when handling INSERT DELAYED statements. If the queue
becomes full, any client that issues an INSERT DELAYED statement waits until there is room in the queue again.
� div_precision_increment
This variable indicates the number of digits of precision by which to increase the result of division
operations performed with the / operator. The default value is 4. The minimum and maximum values are 0 and 30,
respectively. The following example illustrates the effect of increasing the default value.
mysql> SELECT 1/7;
+--------+
| 1/7 |
+--------+
| 0.1429 |
+--------+
mysql> SET div_precision_increment = 12;
mysql> SELECT 1/7;
+----------------+
| 1/7 |
+----------------+
| 0.142857142857 |
+----------------+
This variable was added in MySQL 5.0.6.
� engine_condition_pushdown
This variable applies to NDB. By default it is 0 (OFF): If you execute a query such as SELECT * FROM t WHERE
mycol = 42, where mycol is a non-indexed column, the query is executed as a full table scan on every NDB node.
Each node sends every row to the MySQL server, which applies the WHERE condition. If engine_condition_pushdown
is set to 1 (ON), the condition is "pushed down" to the storage engine and sent to the NDB nodes. Each node
uses the condition to perform the scan, and only sends back to the MySQL server the rows that match the
condition.
This variable was added in MySQL 5.0.3. Before that, the default NDB behavior is the same as for a value of
OFF.
� expire_logs_days
The number of days for automatic binary log removal. The default is 0, which means "no automatic removal."
Possible removals happen at startup and at binary log rotation.
� flush
If ON, the server flushes (synchronizes) all changes to disk after each SQL statement. Normally, MySQL does a
write of all changes to disk only after each SQL statement and lets the operating system handle the
synchronizing to disk. See Section 4.2, "What to Do If MySQL Keeps Crashing". This variable is set to ON if
you start mysqld with the --flush option.
� flush_time
If this is set to a non-zero value, all tables are closed every flush_time seconds to free up resources and
synchronize unflushed data to disk. We recommend that this option be used only on Windows 9x or Me, or on
systems with minimal resources.
� ft_boolean_syntax
The list of operators supported by boolean full-text searches performed using IN BOOLEAN MODE. See
Section 7.1, "Boolean Full-Text Searches".
The default variable value is �+ -><()~*:""&|'. The rules for changing the value are as follows:
� Operator function is determined by position within the string.
� The replacement value must be 14 characters.
� Each character must be an ASCII non-alphanumeric character.
� Either the first or second character must be a space.
� No duplicates are allowed except the phrase quoting operators in positions 11 and 12. These two characters
are not required to be the same, but they are the only two that may be.
� Positions 10, 13, and 14 (which by default are set to `:', `&', and `|') are reserved for future
extensions.
� ft_max_word_len
The maximum length of the word to be included in a FULLTEXT index.
Note: FULLTEXT indexes must be rebuilt after changing this variable. Use REPAIR TABLE tbl_name QUICK.
� ft_min_word_len
The minimum length of the word to be included in a FULLTEXT index.
Note: FULLTEXT indexes must be rebuilt after changing this variable. Use REPAIR TABLE tbl_name QUICK.
� ft_query_expansion_limit
The number of top matches to use for full-text searches performed using WITH QUERY EXPANSION.
� ft_stopword_file
The file from which to read the list of stopwords for full-text searches. All the words from the file are
used; comments are not honored. By default, a built-in list of stopwords is used (as defined in the
myisam/ft_static.c file). Setting this variable to the empty string () disables stopword filtering.
Note: FULLTEXT indexes must be rebuilt after changing this variable or the contents of the stopword file. Use
REPAIR TABLE tbl_name QUICK.
� group_concat_max_len
The maximum allowed result length for the GROUP_CONCAT() function. The default is 1024.
� have_archive
YES if mysqld supports ARCHIVE tables, NO if not.
� have_bdb
YES if mysqld supports BDB tables. DISABLED if --skip-bdb is used.
� have_blackhole_engine
YES if mysqld supports BLACKHOLE tables, NO if not.
� have_compress
YES if the zlib compression library is available to the server, NO if not. If not, the COMPRESS() and
UNCOMPRESS() functions cannot be used.
� have_crypt
YES if the crypt() system call is available to the server, NO if not. If not, the ENCRYPT() function cannot be
used.
� have_csv
YES if mysqld supports ARCHIVE tables, NO if not.
� have_example_engine
YES if mysqld supports EXAMPLE tables, NO if not.
have_federated_engine
YES if mysqld supports FEDERATED tables, NO if not. This variable was added in MySQL 5.0.3.
� have_geometry
YES if the server supports spatial data types, NO if not.
� have_innodb
YES if mysqld supports InnoDB tables. DISABLED if --skip-innodb is used.
� have_isam
In MySQL 5.0, this variable appears only for reasons of backward compatibility. It is always NO because ISAM
tables are no longer supported.
� have_ndbcluster
YES if mysqld supports NDB Cluster tables. DISABLED if --skip-ndbcluster is used.
� have_openssl
YES if mysqld supports SSL connections, NO if not.
� have_query_cache
YES if mysqld supports the query cache, NO if not.
� have_raid
In MySQL 5.0, this variable appears only for reasons of backward compatibility. It is always NO because RAID
tables are no longer supported.
� have_rtree_keys
YES if RTREE indexes are available, NO if not. (These are used for spatial indexes in MyISAM tables.)
� have_symlink
YES if symbolic link support is enabled, NO if not. This is required on Unix for support of the DATA DIRECTORY
and INDEX DIRECTORY table options, and on Windows for support of data directory symlinks.
� init_connect
A string to be executed by the server for each client that connects. The string consists of one or more SQL
statements. To specify multiple statements, separate them by semicolon characters. For example, each client
begins by default with autocommit mode enabled. There is no global system variable to specify that autocommit
should be disabled by default, but init_connect can be used to achieve the same effect:
SET GLOBAL init_connect='SET AUTOCOMMIT=0';
This variable can also be set on the command line or in an option file. To set the variable as just shown using
an option file, include these lines:
[mysqld]
init_connect='SET AUTOCOMMIT=0'
Note that the content of init_connect is not executed for users that have the SUPER privilege. This is done so
that an erroneous value for init_connect does not prevent all clients from connecting. For example, the value
might contain a statement that has a syntax error, thus causing client connections to fail. Not executing
init_connect for users that have the SUPER privilege enables them to open a connection and fix the init_connect
value.
� init_file
The name of the file specified with the --init-file option when you start the server. This should be a file
containing SQL statements that you want the server to execute when it starts. Each statement must be on a
single line and should not include comments.
� init_slave
This variable is similar to init_connect, but is a string to be executed by a slave server each time the SQL
thread starts. The format of the string is the same as for the init_connect variable.
� innodb_xxx
InnoDB system variables are listed in Section 2.4, "InnoDB Startup Options and System Variables".
� interactive_timeout
The number of seconds the server waits for activity on an interactive connection before closing it. An
interactive client is defined as a client that uses the CLIENT_INTERACTIVE option to mysql_real_connect(). See
also wait_timeout.
� join_buffer_size
The size of the buffer that is used for joins that do not use indexes and thus perform full table scans.
Normally, the best way to get fast joins is to add indexes. Increase the value of join_buffer_size to get a
faster full join when adding indexes is not possible. One join buffer is allocated for each full join between
two tables. For a complex join between several tables for which indexes are not used, multiple join buffers
might be necessary.
� key_buffer_size
Index blocks for MyISAM tables are buffered and are shared by all threads. key_buffer_size is the size of the
buffer used for index blocks. The key buffer is also known as the key cache.
The maximum allowable setting for key_buffer_size is 4GB. The effective maximum size might be less, depending
on your available physical RAM and per-process RAM limits imposed by your operating system or hardware
platform.
Increase the value to get better index handling (for all reads and multiple writes) to as much as you can
afford. Using a value that is 25% of total memory on a machine that mainly runs MySQL is quite common.
However, if you make the value too large (for example, more than 50% of your total memory) your system might
start to page and become extremely slow. MySQL relies on the operating system to perform filesystem caching
for data reads, so you must leave some room for the filesystem cache. Consider also the memory requirements of
other storage engines.
For even more speed when writing many rows at the same time, use LOCK TABLES. See Section 2.16, "Speed of
INSERT Statements".
You can check the performance of the key buffer by issuing a SHOW STATUS statement and examining the
Key_read_requests, Key_reads, Key_write_requests, and Key_writes status variables. (See Section 5.4, "SHOW
Syntax".) The Key_reads/Key_read_requests ratio should normally be less than 0.01. The
Key_writes/Key_write_requests ratio is usually near 1 if you are using mostly updates and deletes, but might
be much smaller if you tend to do updates that affect many rows at the same time or if you are using the
DELAY_KEY_WRITE table option.
The fraction of the key buffer in use can be determined using key_buffer_size in conjunction with the
Key_blocks_unused status variable and the buffer block size, which is available from the key_cache_block_size
system variable:
1 - ((Key_blocks_unused � key_cache_block_size) / key_buffer_size)
This value is an approximation because some space in the key buffer may be allocated internally for
administrative structures.
It is possible to create multiple MyISAM key caches. The size limit of 4GB applies to each cache individually,
not as a group. See Section 4.6, "The MyISAM Key Cache".
� key_cache_age_threshold
This value controls the demotion of buffers from the hot sub-chain of a key cache to the warm sub-chain. Lower
values cause demotion to happen more quickly. The minimum value is 100. The default value is 300. See
Section 4.6, "The MyISAM Key Cache".
� key_cache_block_size
The size in bytes of blocks in the key cache. The default value is 1024. See Section 4.6, "The MyISAM Key
Cache".
� key_cache_division_limit
The division point between the hot and warm sub-chains of the key cache buffer chain. The value is the
percentage of the buffer chain to use for the warm sub-chain. Allowable values range from 1 to 100. The
default value is 100. See Section 4.6, "The MyISAM Key Cache".
� language
The language used for error messages.
� large_file_support
Whether mysqld was compiled with options for large file support.
� large_pages
Whether large page support is enabled. This variable was added in MySQL 5.0.3.
� license
The type of license the server has.
� local_infile
Whether LOCAL is supported for LOAD DATA INFILE statements. See Section 5.4, "Security Issues with LOAD DATA
LOCAL".
� locked_in_memory
Whether mysqld was locked in memory with --memlock.
� log
Whether logging of all statements to the general query log is enabled. See Section 10.2, "The General Query
Log".
� log_bin
Whether the binary log is enabled. See Section 10.3, "The Binary Log".
� log_bin_trust_function_creators
This variable applies when binary logging is enabled. It controls whether stored function creators can be
trusted not to create stored functions that will cause unsafe events to be written to the binary log. If set
to 0 (the default), users are not allowed to create or alter stored functions unless they have the SUPER
privilege in addition to the CREATE ROUTINE or ALTER ROUTINE privilege. A setting of 0 also enforces the
restriction that a function must be declared with the DETERMINISTIC characteristic, or with the READS SQL DATA
or NO SQL characteristic. If the variable is set to 1, MySQL does not enforce these restrictions on stored
function creation. See Section 5, "Binary Logging of Stored Routines and Triggers".
This variable was added in MySQL 5.0.16.
� log_bin_trust_routine_creators
This is the old name for log_bin_trust_function_creators. Before MySQL 5.0.16, it also applies to stored
procedures, not just stored functions. As of 5.0.16, this variable is deprecated. It is recognized for
backward compatibility but its use results in a warning.
This variable was added in MySQL 5.0.6.
� log_error
The location of the error log.
� log_queries_not_using_indexes
Whether queries that do not use indexes are logged to the slow query log. See Section 10.4, "The Slow Query
Log". This variable was added in MySQL 5.0.23.
� log_slave_updates
Whether updates received by a slave server from a master server should be logged to the slave's own binary
log. Binary logging must be enabled on the slave for this variable to have any effect. See Section 8,
"Replication Startup Options".
� log_slow_queries
Whether slow queries should be logged. "Slow" is determined by the value of the long_query_time variable. See
Section 10.4, "The Slow Query Log".
� log_warnings
Whether to produce additional warning messages. It is enabled(1) by default. Aborted connections are not
logged to the error log unless the value is greater than 1.
� long_query_time
If a query takes longer than this many seconds, the server increments the Slow_queries status variable. If you
are using the --log-slow-queries option, the query is logged to the slow query log file. This value is
measured in real time, not CPU time, so a query that is under the threshold on a lightly loaded system might
be above the threshold on a heavily loaded one. The minimum value is 1. The default is 10. See Section 10.4,
"The Slow Query Log".
� low_priority_updates
If set to 1, all INSERT, UPDATE, DELETE, and LOCK TABLE WRITE statements wait until there is no pending SELECT
or LOCK TABLE READ on the affected table. This variable previously was named sql_low_priority_updates.
� lower_case_file_system
This variable describes the case sensitivity of filenames on the filesystem where the data directory is
located. OFF means filenames are case sensitive, ON means they are not case sensitive.
� lower_case_table_names
If set to 1, table names are stored in lowercase on disk and table name comparisons are not case sensitive. If
set to 2 table names are stored as given but compared in lowercase. This option also applies to database names
and table aliases. See Section 2.2, "Identifier Case Sensitivity".
If you are using InnoDB tables, you should set this variable to 1 on all platforms to force names to be
converted to lowercase.
You should not set this variable to 0 if you are running MySQL on a system that does not have case-sensitive
filenames (such as Windows or Mac OS X). If this variable is not set at startup and the filesystem on which
the data directory is located does not have case-sensitive filenames, MySQL automatically sets
lower_case_table_names to 2.
� max_allowed_packet
The maximum size of one packet or any generated/intermediate string.
The packet message buffer is initialized to net_buffer_length bytes, but can grow up to max_allowed_packet
bytes when needed. This value by default is small, to catch large (possibly incorrect) packets.
You must increase this value if you are using large BLOB columns or long strings. It should be as big as the
largest BLOB you want to use. The protocol limit for max_allowed_packet is 1GB.
� max_binlog_cache_size
If a multiple-statement transaction requires more than this amount of memory, the server generates a
Multi-statement transaction required more than 'max_binlog_cache_size' bytes of storage error.
� max_binlog_size
If a write to the binary log causes the current log file size to exceed the value of this variable, the server
rotates the binary logs (closes the current file and opens the next one). You cannot set this variable to more
than 1GB or to less than 4096 bytes. The default value is 1GB.
A transaction is written in one chunk to the binary log, so it is never split between several binary logs.
Therefore, if you have big transactions, you might see binary logs larger than max_binlog_size.
If max_relay_log_size is 0, the value of max_binlog_size applies to relay logs as well.
� max_connect_errors
If there are more than this number of interrupted connections from a host, that host is blocked from further
connections. You can unblock blocked hosts with the FLUSH HOSTS statement.
� max_connections
The number of simultaneous client connections allowed. Increasing this value increases the number of file
descriptors that mysqld requires. See Section 4.8, "How MySQL Opens and Closes Tables", for comments on file
descriptor limits. See also Section 2.6, "Too many connections".
� max_delayed_threads
Do not start more than this number of threads to handle INSERT DELAYED statements. If you try to insert data
into a new table after all INSERT DELAYED threads are in use, the row is inserted as if the DELAYED attribute
wasn't specified. If you set this to 0, MySQL never creates a thread to handle DELAYED rows; in effect, this
disables DEL