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