myisamchk

MyISAM table-maintenance utility

   myisamchk  Ver 2.7 for debian-linux-gnu at i686
By Monty, for your professional use
This software comes with NO WARRANTY: see the PUBLIC for details.

Description, check and repair of MyISAM tables.
Used without options all tables on the command will be checked for errors
Usage: myisamchk [OPTIONS] tables[.MYI]

Global options:
  -H, --HELP          Display this help and exit.
  -?, --help          Display this help and exit.
  -O, --set-variable var=option.
                      Change the value of a variable. Please note that
                      this option is deprecated; you can set variables
                      directly with '--variable-name=value'.
  -t, --tmpdir=path   Path for temporary files. Multiple paths can be
                      specified, separated by colon (:), they will be used
                      in a round-robin fashion.
  -s, --silent	      Only print errors.  One can use two -s to make
		      myisamchk very silent.
  -v, --verbose       Print more information. This can be used with
                      --description and --check. Use many -v for more verbosity.
  -V, --version       Print version and exit.
  -w, --wait          Wait if table is locked.

Check options (check is the default action for myisamchk):
  -c, --check	      Check table for errors.
  -e, --extend-check  Check the table VERY throughly.  Only use this in
                      extreme cases as myisamchk should normally be able to
                      find out if the table is ok even without this switch.
  -F, --fast	      Check only tables that haven't been closed properly.
  -C, --check-only-changed
		      Check only tables that have changed since last check.
  -f, --force         Restart with '-r' if there are any errors in the table.
		      States will be updated as with '--update-state'.
  -i, --information   Print statistics information about table that is checked.
  -m, --medium-check  Faster than extend-check, but only finds 99.99% of
		      all errors.  Should be good enough for most cases.
  -U  --update-state  Mark tables as crashed if you find any errors.
  -T, --read-only     Don't mark table as checked.

Repair options (When using '-r' or '-o'):
  -B, --backup	      Make a backup of the .MYD file as 'filename-time.BAK'.
  --correct-checksum  Correct checksum information for table.
  -D, --data-file-length=#  Max length of data file (when recreating data
                      file when it's full).
  -e, --extend-check  Try to recover every possible row from the data file
		      Normally this will also find a lot of garbage rows;
		      Don't use this option if you are not totally desperate.
  -f, --force         Overwrite old temporary files.
  -k, --keys-used=#   Tell MyISAM to update only some specific keys. # is a
	              bit mask of which keys to use. This can be used to
		      get faster inserts.
  --max-record-length=#
                      Skip rows bigger than this if myisamchk can't allocate
		      memory to hold it.
  -r, --recover       Can fix almost anything except unique keys that aren't
                      unique.
  -n, --sort-recover  Forces recovering with sorting even if the temporary
		      file would be very big.
  -p, --parallel-recover
                      Uses the same technique as '-r' and '-n', but creates
                      all the keys in parallel, in different threads.
  -o, --safe-recover  Uses old recovery method; Slower than '-r' but can
		      handle a couple of cases where '-r' reports that it
		      can't fix the data file.
  --character-sets-dir=...
                      Directory where character sets are.
  --set-collation=name
 		      Change the collation used by the index.
  -q, --quick         Faster repair by not modifying the data file.
                      One can give a second '-q' to force myisamchk to
		      modify the original datafile in case of duplicate keys.
		      NOTE: Tables where the data file is currupted can't be
		      fixed with this option.
  -u, --unpack        Unpack file packed with myisampack.

Other actions:
  -a, --analyze	      Analyze distribution of keys. Will make some joins in
		      MySQL faster.  You can check the calculated distribution
		      by using '--description --verbose table_name'.
  --stats_method=name Specifies how index statistics collection code should
                      treat NULLs. Possible values of name are "nulls_unequal"
                      (default for 4.1/5.0), "nulls_equal" (emulate 4.0), and 
                      "nulls_ignored".
  -d, --description   Prints some information about table.
  -A, --set-auto-increment[=value]
		      Force auto_increment to start at this or higher value
		      If no value is given, then sets the next auto_increment
		      value to the highest used value for the auto key + 1.
  -S, --sort-index    Sort index blocks.  This speeds up 'read-next' in
		      applications.
  -R, --sort-records=#
		      Sort records according to an index.  This makes your
		      data much more localized and may speed up things
		      (It may be VERY slow to do a sort the first time!).
  -b,  --block-search=#
                       Find a record, a block at given offset belongs to.

Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf /usr/etc/my.cnf ~/.my.cnf 
The following groups are read: myisamchk
The following options may be given as the first argument:
--print-defaults        Print the program argument list and exit.
--no-defaults           Don't read default options from any option file.
--defaults-file=#       Only read default options from the given file #.
--defaults-extra-file=# Read this file after the global files are read.

Variables (--variable-name=value)
and boolean options {FALSE|TRUE}  Value (after reading options)
--------------------------------- -----------------------------
character-sets-dir                (No default value)
data-file-length                  0
keys-used                         18446744073709551615
max-record-length                 9223372036854775807
set-auto-increment                0
set-collation                     (No default value)
sort-records                      0
tmpdir                            (No default value)
key_buffer_size                   520192
key_cache_block_size              1024
myisam_block_size                 1024
read_buffer_size                  262136
write_buffer_size                 262136
sort_buffer_size                  2097144
sort_key_blocks                   16
decode_bits                       9
ft_min_word_len                   4
ft_max_word_len                   84
ft_stopword_file                  (No default value)
stats_method                      nulls_unequal