MySQL连接查询流程源码

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版本: 不详, 仅做参考用

初始化:

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1. main
   
2.     |–mysqld
3.         |–my_init // 初始话线程变量，互斥量
4.         |–load_defaults // 获取配置
5.         |–init_common_variables // 初始化变量
6.         |–init_server_components // 初始化插件
7.         | |–plugin_init
8.         | | |–plugin_initialize
9.         | |–initialize_storage_engine
10.         |–network_init // 监听网络
11.         |–grant_init
12.         |–servers_init
13.         |–udf_init

插件启动:

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1. main
   
2.     |–mysqld_main
3.         |–init_server_components
4.             |–plugin_init
5.                 |–plugin_initialize
6.                     |–ha_initialize_handlerton
7.                         |–innobase_init

登录过程:

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1. main
   
2.     |–mysqld_main
3.         |–network_init // 建立socket监听，一个针对网络，一个针对unix域
4.         |–handle_connections_sockets
5.             |–poll
6.             |–mysql_socket_accept // 和客户端建立连接
7.             |–create_new_thread // 针对每个socket连接建立一个新的线程
8.                 |–create_thread_to_handle_connection
9.                     |–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
10.                     |–mysql_thread_create(启动的线程执行函数，inline_mysql_thread_create)
11.                         |–spawn_thread_v1
12.                             |–pthread_create(pfs_spawn_thread)

处理连接:

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1. pfs_spawn_thread
   
2.     |–handle_one_connection
3.         |–do_handle_one_connection
4.             |–MYSQL_CALLBACK_ELSE(thread_scheduler, init_new_connection_thread, (), 0)
5.             | |–init_new_connection_handler_thread
6.             |–thd_prepare_connection
7.             | |–login_connection // 判断是否可以login，不可以则断开连接返回错误
8.             | | |–check_connection
9.             | | | |–acl_authenticate
10.             | | | |–do_auth_once
11.             | | | |–native_password_authenticate
12.             | | | |–server_mpvio_write_packet
13.             | | | | |–send_server_handshake_packet // 发送handshake包到客户端
14.             | | | | |–my_net_write
15.             | | | | | |–net_write_buff // 将数据写入到内存
16.             | | | | |–net_flush // 将内存中数据发送到网络
17.             | | | |–server_mpvio_read_packet // 从客户端接收Login Request信息
18.             | | | |–my_net_read
19.             | | |–Protocol::end_statement
20.             | | |–Protocol::send_ok
21.             | | |–net_send_ok // 发送response ok
22.             | | |–my_net_write
23.             | |–prepare_new_connection_state
24.             |–do_command
25.                 |–dispatch_command
26.                     |–mysql_parse

select命令:

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1. pfs_swpawn_thread
   
2.     |–handle_one_connection
3.         |–do_handle_one_connection
4.             |–do_command
5.                 |–dispatch_command
6.                     |–mysql_parse
7.                         |–parse_sql
8.                         | |–MYSQLparse
9.                         |–mysql_execute_command
10.                             |–select_precheck
11.                             | |–check_table_access
12.                             |–execute_sqlcom_select
13.                             | |–open_normal_and_derived_tables
14.                             | |–open_tables
15.                             | | |–open_and_process_table
16.                             | | |–open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx)
17.                             | | |–Table_cache::get_table
18.                             | | |–get_table_share_with_discover
19.                             | | | |–get_table_share
20.                             | | | |–open_table_def
21.                             | | |–my_malloc // 申请表数据结构
22.                             | | |–open_table_from_share
23.                             | | |–handler::ha_open
24.                             | | |–ha_innobase::open
25.                             | | |–dict_table_open_on_name
26.                             | | |–dict_load_table
27.                             | | |–btr_pcur_is_on_user_rec
28.                             | | |–dict_load_table_low
29.                             | | | |–dict_mem_table_create
30.                             | | |–fil_space_for_table_exists_in_mem
31.                             | | |–fil_open_single_table_tablespace // 打开表空间文件
32.                             | |–mysql_handle_derived
33.                             |–handle_select
34.                                 |–mysql_select
35.                                     |–mysql_prepare_select
36.                                     | |–JOIN::prepare
37.                                     |–mysql_execute_select
38.                                         |–JOIN::exec
39.                                             |–select_send::send_result_set_metadata
40.                                             | |–Protocol::send_result_set_metadata
41.                                             |–do_select
42.                                                 |–sub_select
43.                                                     |–evaluate_join_record
44.                                                         |–end_send
45.                                                             |–select_send::send_data
46.                                                                 |–Protocol::write