(mysql.info.gz) myisamchk general options

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 5.7.3.2 General Options for `myisamchk'
 .......................................
 
 The options described in this section can be used for any type of table
 maintenance operation performed by `myisamchk'.  The sections following
 this one describe options that pertain only to specific operations,
 such as table checking or repairing.
 
 `--help, -?'
      Display a help message and exit.
 
 `--debug=DEBUG_OPTIONS, -# DEBUG_OPTIONS'
      Write a debugging log. The DEBUG_OPTIONS string often is
      `'d:t:o,FILE_NAME''.
 
 `--silent, -s'
      Silent mode.  Write output only when errors occur. You can use `-s'
      twice (`-ss') to make `myisamchk' very silent.
 
 `--verbose, -v'
      Verbose mode.  Print more information. This can be used with `-d'
      and `-e'. Use `-v' multiple times (`-vv', `-vvv') for even more
      output.
 
 `--version, -V'
      Display version information and exit.
 
 `--wait, -w'
      Instead of terminating with an error if the table is locked, wait
      until the table is unlocked before continuing.  Note that if you
      are running `mysqld' with the `--skip-external-locking' option,
      the table can be locked only by another `myisamchk' command.
 
 
 You can also set the following variables by using `--VAR_NAME=VALUE'
 options:
 
 *Variable*                *Default Value*
 `decode_bits'             9
 `ft_max_word_len'         version-dependent
 `ft_min_word_len'         4
 `ft_stopword_file'        built-in list
 `key_buffer_size'         523264
 `myisam_block_size'       1024
 `read_buffer_size'        262136
 `sort_buffer_size'        2097144
 `sort_key_blocks'         16
 `write_buffer_size'       262136
 
 It is also possible to set variables by using
 `--set-variable=VAR_NAME=VALUE' or `-O VAR_NAME=VALUE' syntax. However,
 this syntax is deprecated as of MySQL 4.0.
 
 The possible `myisamchk' variables and their default values can be
 examined with `myisamchk --help':
 
 `sort_buffer_size' is used when the keys are repaired by sorting keys,
 which is the normal case when you use `--recover'.
 
 `key_buffer_size' is used when you are checking the table with
 `--extend-check' or when the keys are repaired by inserting keys row by
 row into the table (like when doing normal inserts). Repairing through
 the key buffer is used in the following cases:
 
    * You use `--safe-recover'.
 
    * The temporary files needed to sort the keys would be more than
      twice as big as when creating the key file directly.  This is
      often the case when you have large key values for  `CHAR',
      `VARCHAR', or `TEXT' columns, because the sort operation needs to
      store the complete key values as it proceeds. If you have lots of
      temporary space and you can force `myisamchk' to repair by
      sorting, you can use the `--sort-recover' option.
 
 
 Repairing through the key buffer takes much less disk space than using
 sorting, but is also much slower.
 
 If you want a faster repair, set the `key_buffer_size' and
 `sort_buffer_size' variables to about 25% of your available memory.
 You can set both variables to large values, because only one of them is
 used at a time.
 
 `myisam_block_size' is the size used for index blocks. It is available
 as of MySQL 4.0.0.
 
 The `ft_min_word_len' and `ft_max_word_len' variables are available as
 of MySQL 4.0.0.  `ft_stopword_file' is available as of MySQL 4.0.19.
 
 `ft_min_word_len' and `ft_max_word_len' indicate the minimum and
 maximum word length for `FULLTEXT' indexes. `ft_stopword_file' names
 the stopword file. These need to be set under the following
 circumstances.
 
 If you use `myisamchk' to perform an operation that modifies table
 indexes (such as repair or analyze), the `FULLTEXT' indexes are rebuilt
 using the default full-text parameter values for minimum and maximum
 word length and the stopword file unless you specify otherwise.  This
 can result in queries failing.
 
 The problem occurs because these parameters are known only by the
 server.  They are not stored in `MyISAM' index files.  To avoid the
 problem if you have modified the minimum or maximum word length or the
 stopword file in the server, specify the same `ft_min_word_len',
 `ft_max_word_len', and `ft_stopword_file' values to `myisamchk' that
 you use for `mysqld'. For example, if you have set the minimum word
 length to 3, you can repair a table with `myisamchk' like this:
 
      shell> myisamchk --recover --ft_min_word_len=3 TBL_NAME.MYI
 
 To ensure that `myisamchk' and the server use the same values for
 full-text parameters, you can place each one in both the `[mysqld]' and
 `[myisamchk]' sections of an option file:
 
      [mysqld]
      ft_min_word_len=3
 
      [myisamchk]
      ft_min_word_len=3
 
 An alternative to using `myisamchk' is to use the `REPAIR TABLE',
 `ANALYZE TABLE', `OPTIMIZE TABLE', or `ALTER TABLE'.  These statements
 are performed by the server, which knows the proper full-text parameter
 values to use.
 

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