MySQL连接查询流程源码分析

初始化

main    |-mysqld        |-my_init   // 初始话线程变量，互斥量        |-load_defaults // 获取配置        |-init_common_variables // 初始化变量        |-init_server_components    // 初始化插件        |   |-plugin_init        |   |   |-plugin_initialize        |   |-initialize_storage_engine        |-network_init  // 监听网络        |-grant_init        |-servers_init        |-udf_init

插件启动

main    |-mysqld_main        |-init_server_components            |-plugin_init                |-plugin_initialize                    |-ha_initialize_handlerton                        |-innobase_init

登录过程

main    |-mysqld_main        |-network_init      // 建立socket监听，一个针对网络，一个针对unix域        |-handle_connections_sockets            |-poll            |-mysql_socket_accept   // 和客户端建立连接            |-create_new_thread     // 针对每个socket连接建立一个新的线程                |-create_thread_to_handle_connection                    |-waiting_thd_list->push_back(thd);mysql_cond_signal(&COND_thread_cache);   // 已有连接处理线程时，通过信号唤醒，处理线程函数为pfs_spawn_thread                    |-mysql_thread_create(启动的线程执行函数，inline_mysql_thread_create)                        |-spawn_thread_v1                            |-pthread_create(pfs_spawn_thread)

处理连接

pfs_spawn_thread    |-handle_one_connection        |-do_handle_one_connection            |-MYSQL_CALLBACK_ELSE(thread_scheduler, init_new_connection_thread, (), 0)            |   |-init_new_connection_handler_thread            |-thd_prepare_connection            |   |-login_connection  // 判断是否可以login，不可以则断开连接返回错误            |   |   |-check_connection            |   |   |   |-acl_authenticate            |   |   |       |-do_auth_once            |   |   |           |-native_password_authenticate            |   |   |               |-server_mpvio_write_packet            |   |   |               |   |-send_server_handshake_packet  // 发送handshake包到客户端            |   |   |               |       |-my_net_write            |   |   |               |       |   |-net_write_buff // 将数据写入到内存            |   |   |               |       |-net_flush // 将内存中数据发送到网络            |   |   |               |-server_mpvio_read_packet  // 从客户端接收Login Request信息            |   |   |                   |-my_net_read            |   |   |-Protocol::end_statement            |   |       |-Protocol::send_ok            |   |           |-net_send_ok           // 发送response ok            |   |               |-my_net_write            |   |-prepare_new_connection_state            |-do_command                |-dispatch_command                    |-mysql_parse       

处理命令select

pfs_swpawn_thread    |-handle_one_connection        |-do_handle_one_connection            |-do_command                |-dispatch_command                    |-mysql_parse                        |-parse_sql                        |   |-MYSQLparse                        |-mysql_execute_command                            |-select_precheck                            |   |-check_table_access                            |-execute_sqlcom_select                            |   |-open_normal_and_derived_tables                            |       |-open_tables                            |       |   |-open_and_process_table                            |       |       |-open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx)                            |       |           |-Table_cache::get_table                            |       |           |-get_table_share_with_discover                             |       |           |   |-get_table_share                            |       |           |       |-open_table_def                                                                    |       |           |-my_malloc // 申请表数据结构                            |       |           |-open_table_from_share                            |       |               |-handler::ha_open                            |       |                   |-ha_innobase::open                            |       |                       |-dict_table_open_on_name                            |       |                           |-dict_load_table                            |       |                               |-btr_pcur_is_on_user_rec                            |       |                               |-dict_load_table_low                            |       |                               |   |-dict_mem_table_create                            |       |                               |-fil_space_for_table_exists_in_mem                            |       |                               |-fil_open_single_table_tablespace // 打开表空间文件                            |       |-mysql_handle_derived                                          |-handle_select                                |-mysql_select                                    |-mysql_prepare_select                                    |   |-JOIN::prepare                                    |-mysql_execute_select                                        |-JOIN::exec                                            |-select_send::send_result_set_metadata                                            |   |-Protocol::send_result_set_metadata                                            |-do_select                                                |-sub_select                                                    |-evaluate_join_record                                                        |-end_send                                                            |-select_send::send_data                                                                |-Protocol::write