content_image/709010.jpg content_image/709011.jpg content_image/709012.jpg
considered unequal, and each NULL  forms a distinct value group of size 1. For nulls_ignored , NULL values are ignored. 

The method that is used for generating table statistics influences how the optimizer chooses indexes for query execution, as described in Section 8.3.8, “InnoDB and MyISAM Index Statistics Collection” . 

• myisam_use_mmap 

<img src='content_image/709010.jpg'>

Use memory mapping for reading and writing MyISAM  tables. 

• mysql_native_password_proxy_users 

<img src='content_image/709011.jpg'>

This variable controls whether the mysql_native_password  built-in authentication plugin supports proxy users. It has no effect unless the check_proxy_users  system variable is enabled. For information about user proxying, see Section 6.2.18, “Proxy Users” . 

• named_pipe 

<img src='content_image/709012.jpg'>

(Windows only.) Indicates whether the server supports connections over named pipes. 

