<b>MySQL数据库中部份数据破坏恢复历程</b>[MySQL防范]

注:此为记录我当时操作的全部历程
d:\documents and settings\administrator>c:
c:\>cd MySQL
c:\mysql>cd data
c:\mysql\data>cd hw_enterprice
c:\mysql\data\hw_enterprice>myisamchk function_products.frm
'myisamchk' 不是内部或外部号令,也不是可运行的程序或批处理文件.
c:\mysql\data\hw_enterprice>cd\
c:\>cd mysql
c:\mysql>cd bin
注:查看myisamchk的帮忙信息
c:\mysql\bin>myisamchk
myisamchk  ver 2.6 for win95/win98 at i32
by monty, for your professional use
this software comes with no warranty: see the public for details.

description, check and repair of isam tables.
used without options all tables on the command will be checked for errors
usage: myisamchk [options] tables[.myi]

global options:
  -#, --debug=...     output debug log. often this is 'd:t:o,filename'
  -?, --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
  -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!
  -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.
                      this is alpha code. use at your own risk!
  -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-character-set=name
                      change the character set 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
  -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'.
  -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
c:\mysql\bin>myisamchk c:\mysql\data\hw_enterprice\function_products.frm
myisamchk: error: 'c:\mysql\data\hw_enterprice\function_products.frm' is not a m
yisam-table

c:\mysql\bin>myisamchk c:\mysql\data\hw_enterprice\function_products.myi
checking myisam file: c:\mysql\data\hw_enterprice\function_products.myi
data records:   85207   deleted blocks:      39
myisamchk: warning: table is marked as crashed
myisamchk: warning: 1 clients is using or hasn't closed the table properly
- check file-size
- check key delete-chain
- check record delete-chain
myisamchk: error: record delete-link-chain corrupted
- check index reference
- check data record references index: 1
- check data record references index: 2
- check data record references index: 3
- check record links
myisamchk: error: wrong bytesec: 0-195-171 at linkstart: 841908
myisam-table 'c:\MySQL\data\hw_enterprice\function_products.myi' is corrupted
fix it using switch "-r" or "-o"

c:\MySQL\bin>myisamchk --recover --quick  c:\MySQL\data\hw_enterprice\function_p
roducts.myi
- check key delete-chain
- check record delete-chain
myisamchk: error: record delete-link-chain corrupted
myisamchk: error: quick-recover aborted; run recovery without switch 'q'
updating myisam file: c:\MySQL\data\hw_enterprice\function_products.myi
myisam-table 'c:\MySQL\data\hw_enterprice\function_products.myi' is not fixed be
cause of errors
try fixing it by using the --safe-recover (-o) or the --force (-f) option

c:\MySQL\bin>myisamchk --safe-recover  c:\MySQL\data\hw_enterprice\function_prod
ucts.myi
- recovering (with keycache) myisam-table 'c:\MySQL\data\hw_enterprice\function_
products.myi'
data records: 85207
wrong bytesec:   0-195-171 at     841908; skipped
data records: 85215

% myisamchk --recover --quick /path/to/tblname 
% myisamchk --recover /path/to/tblname 
% myisamchk --safe-recover /path/to/tblname