Documentation Home
MySQL 8.0 参考手册  / 第 27 章 MySQL 性能模式  /  27.15 性能模式系统变量

27.15 性能模式系统变量

性能模式实现了几个提供配置信息的系统变量:

Press CTRL+C to copy
mysql> SHOW VARIABLES LIKE 'perf%'; +----------------------------------------------------------+-------+ | Variable_name | Value | +----------------------------------------------------------+-------+ | performance_schema | ON | | performance_schema_accounts_size | -1 | | performance_schema_digests_size | 10000 | | performance_schema_events_stages_history_long_size | 10000 | | performance_schema_events_stages_history_size | 10 | | performance_schema_events_statements_history_long_size | 10000 | | performance_schema_events_statements_history_size | 10 | | performance_schema_events_transactions_history_long_size | 10000 | | performance_schema_events_transactions_history_size | 10 | | performance_schema_events_waits_history_long_size | 10000 | | performance_schema_events_waits_history_size | 10 | | performance_schema_hosts_size | -1 | | performance_schema_max_cond_classes | 80 | | performance_schema_max_cond_instances | -1 | | performance_schema_max_digest_length | 1024 | | performance_schema_max_file_classes | 50 | | performance_schema_max_file_handles | 32768 | | performance_schema_max_file_instances | -1 | | performance_schema_max_index_stat | -1 | | performance_schema_max_memory_classes | 320 | | performance_schema_max_metadata_locks | -1 | | performance_schema_max_mutex_classes | 350 | | performance_schema_max_mutex_instances | -1 | | performance_schema_max_prepared_statements_instances | -1 | | performance_schema_max_program_instances | -1 | | performance_schema_max_rwlock_classes | 40 | | performance_schema_max_rwlock_instances | -1 | | performance_schema_max_socket_classes | 10 | | performance_schema_max_socket_instances | -1 | | performance_schema_max_sql_text_length | 1024 | | performance_schema_max_stage_classes | 150 | | performance_schema_max_statement_classes | 192 | | performance_schema_max_statement_stack | 10 | | performance_schema_max_table_handles | -1 | | performance_schema_max_table_instances | -1 | | performance_schema_max_table_lock_stat | -1 | | performance_schema_max_thread_classes | 50 | | performance_schema_max_thread_instances | -1 | | performance_schema_session_connect_attrs_size | 512 | | performance_schema_setup_actors_size | -1 | | performance_schema_setup_objects_size | -1 | | performance_schema_users_size | -1 | +----------------------------------------------------------+-------+

Performance Schema 系统变量可以在服务器启动时在命令行或选项文件中设置,许多可以在运行时设置。请参阅 第 27.13 节,“性能模式选项和变量参考”

如果未明确设置,性能模式会在服务器启动时自动调整其几个参数的值。有关详细信息,请参阅 第 27.3 节,“性能模式启动配置”

Performance Schema 系统变量具有以下含义: