MySQL:简单记录character_set_server影响参数

GLOBAL 级别继承

/* Set collactions that depends on the default collation */
  global_system_variables.collation_server=  default_charset_info;
  global_system_variables.collation_database=  default_charset_info;

  if (is_supported_parser_charset(default_charset_info))
  {
    global_system_variables.collation_connection= default_charset_info;
    global_system_variables.character_set_results= default_charset_info;
    global_system_variables.character_set_client= default_charset_info;
  }
  else
  {
    sql_print_information("'%s' can not be used as client character set. "
                          "'%s' will be used as default client character set.",
                          default_charset_info->csname,
                          my_charset_latin1.csname);
    global_system_variables.collation_connection= &my_charset_latin1;
    global_system_variables.character_set_results= &my_charset_latin1;
    global_system_variables.character_set_client= &my_charset_latin1;
  }


static Sys_var_struct Sys_character_set_server(
       "character_set_server", "The default character set",
       SESSION_VAR(collation_server), NO_CMD_LINE,
       offsetof(CHARSET_INFO, csname), DEFAULT(&default_charset_info), 
       NO_MUTEX_GUARD, IN_BINLOG, ON_CHECK(check_charset_not_null));

mysql> show global variables like '%char%';
+--------------------------+----------------+
| Variable_name            | Value          |
+--------------------------+----------------+
| character_set_client     | latin1         | --继承
| character_set_connection | latin1         | --继承
| character_set_database   | latin1         | --继承 建立数据库默认字符集
| character_set_filesystem | binary         |
| character_set_results    | latin1         | --继承
| character_set_server     | latin1         | --继承来源
| character_set_system     | utf8           | --内部使用UTF8比如临时表
+--------------------------+----------------+

+---------------------------+-------------------+
| Variable_name             | Value             |
+---------------------------+-------------------+
| collation_connection      | latin1_swedish_ci | --继承
| collation_database        | latin1_swedish_ci | --继承
| collation_server          | latin1_swedish_ci | --继承
| protocol_version          | 10                |
| slave_compressed_protocol | OFF               |
+---------------------------+-------------------+

session 级别 客户端将依据OS字符集更改，set names命令也影响这几个参数：

            /*
              Check if the changed variable was charset. In that case we need to
              update mysql->charset.
              */
            if (!strncmp(data->str, "character_set_client", data->length))
              is_charset= 1;
            else
              is_charset= 0;

export LC_ALL=zh_CN.GBK
export LANG=zh_CN.GBK

mysql> show  variables like '%char%';
+--------------------------+----------------+
| Variable_name            | Value          |
+--------------------------+----------------+
| character_set_client     | gbk            | --影响
| character_set_connection | gbk            | --影响
| character_set_database   | latin1         |
| character_set_filesystem | binary         |
| character_set_results    | gbk            | --影响
| character_set_server     | latin1         |
| character_set_system     | utf8           |
+--------------------------+----------------+
8 rows in set (0.00 sec)

mysql> exit
Bye
[root@mysqltest2 ~]# locale
LANG=zh_CN.GBK
LC_CTYPE="zh_CN.GBK"
LC_NUMERIC="zh_CN.GBK"
LC_TIME="zh_CN.GBK"
LC_COLLATE="zh_CN.GBK"
LC_MONETARY="zh_CN.GBK"
LC_MESSAGES="zh_CN.GBK"
LC_PAPER="zh_CN.GBK"
LC_NAME="zh_CN.GBK"
LC_ADDRESS="zh_CN.GBK"
LC_TELEPHONE="zh_CN.GBK"
LC_MEASUREMENT="zh_CN.GBK"
LC_IDENTIFICATION="zh_CN.GBK"
LC_ALL=zh_CN.GBK