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