content_image/791898.jpg content_image/791901.jpg content_image/791902.jpg
Maximum Value 

7 

The default mode value to use for the WEEK()  function. See Section 12.7, “Date and Time Functions” . 

• delay_key_write 

<img src='content_image/791898.jpg'>

This variable specifies how to use delayed key writes. It applies only to MyISAM  tables. Delayed key writing causes key buffers not to be flushed between writes. See also Section 16.2.1, “MyISAM Startup Options” . 

This variable can have one of the following values to affect handling of the DELAY_KEY_WRITE  table option that can be used in CREATE TABLE  statements. 

<img src='content_image/791901.jpg'>

<img src='content_image/791902.jpg'>

## Note 

If you set this variable to ALL , you should not use MyISAM  tables from within another program (such as another MySQL server or myisamchk ) when the tables are in use. Doing so leads to index corruption. 

If DELAY_KEY_WRITE  is enabled for a table, the key buffer is not flushed for the table on every index update, but only when the table is closed. This speeds up writes on keys a lot, but if you use this feature, you should add automatic checking of all MyISAM  tables by starting the server with the myisam_recover_options  system variable set (for example, 

