Getting Information About a Table

To get a description of a table or statistics about it, use the commands shown here. We explain some of the information in more detail later:

Example of myisamchk -d output:

 MyISAM file:     company.MYI
 Record format:   Fixed length
 Data records:    1403698  Deleted blocks:         0
 Recordlength:    226
 table description:
 Key Start Len Index   Type
 1   2     8   unique  double
 2   15    10  multip. text packed stripped
 3   219   8   multip. double
 4   63    10  multip. text packed stripped
 5   167   2   multip. unsigned short
 6   177   4   multip. unsigned long
 7   155   4   multip. text
 8   138   4   multip. unsigned long
 9   177   4   multip. unsigned long
     193   1           text
 

Example of myisamchk -d -v output:

 MyISAM file:         company
 Record format:       Fixed length
 File-version:        1
 Creation time:       1999-10-30 12:12:51
 Recover time:        1999-10-31 19:13:01
 Status:              checked
 Data records:           1403698  Deleted blocks:              0
 Datafile parts:         1403698  Deleted data:                0
 Datafilepointer (bytes):      3  Keyfile pointer (bytes):     3
 Max datafile length: 3791650815  Max keyfile length: 4294967294
 Recordlength:               226
 table description:
 Key Start Len Index   Type                  Rec/key     Root Blocksize
 1   2     8   unique  double                      1 15845376      1024
 2   15    10  multip. text packed stripped        2 25062400      1024
 3   219   8   multip. double                     73 40907776      1024
 4   63    10  multip. text packed stripped        5 48097280      1024
 5   167   2   multip. unsigned short           4840 55200768      1024
 6   177   4   multip. unsigned long            1346 65145856      1024
 7   155   4   multip. text                     4995 75090944      1024
 8   138   4   multip. unsigned long              87 85036032      1024
 9   177   4   multip. unsigned long             178 96481280      1024
     193   1           text
 

Example of myisamchk -eis output:

 Checking MyISAM file: company
 Key:  1:  Keyblocks used:  97%  Packed:    0%  Max levels:  4
 Key:  2:  Keyblocks used:  98%  Packed:   50%  Max levels:  4
 Key:  3:  Keyblocks used:  97%  Packed:    0%  Max levels:  4
 Key:  4:  Keyblocks used:  99%  Packed:   60%  Max levels:  3
 Key:  5:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 Key:  6:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 Key:  7:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 Key:  8:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 Key:  9:  Keyblocks used:  98%  Packed:    0%  Max levels:  4
 Total:    Keyblocks used:  98%  Packed:   17%
 Records:          1403698    M.recordlength:     226
 Packed:             0%
 Recordspace used:     100%   Empty space:          0%
 Blocks/Record:   1.00
 Record blocks:    1403698    Delete blocks:        0
 Recorddata:     317235748    Deleted data:         0
 Lost space:             0    Linkdata:             0
 User time 1626.51, System time 232.36
 Maximum resident set size 0, Integral resident set size 0
 Non physical pagefaults 0, Physical pagefaults 627, Swaps 0
 Blocks in 0 out 0, Messages in 0 out 0, Signals 0
 Voluntary context switches 639, Involuntary context switches 28966
 

Example of myisamchk -eiv output:

 Checking MyISAM file: company
 Data records: 1403698   Deleted blocks:       0
 - check file-size
 - check delete-chain
 block_size 1024:
 index  1:
 index  2:
 index  3:
 index  4:
 index  5:
 index  6:
 index  7:
 index  8:
 index  9:
 No recordlinks
 - check index reference
 - check data record references index: 1
 Key:  1:  Keyblocks used:  97%  Packed:    0%  Max levels:  4
 - check data record references index: 2
 Key:  2:  Keyblocks used:  98%  Packed:   50%  Max levels:  4
 - check data record references index: 3
 Key:  3:  Keyblocks used:  97%  Packed:    0%  Max levels:  4
 - check data record references index: 4
 Key:  4:  Keyblocks used:  99%  Packed:   60%  Max levels:  3
 - check data record references index: 5
 Key:  5:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 - check data record references index: 6
 Key:  6:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 - check data record references index: 7
 Key:  7:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 - check data record references index: 8
 Key:  8:  Keyblocks used:  99%  Packed:    0%  Max levels:  3
 - check data record references index: 9
 Key:  9:  Keyblocks used:  98%  Packed:    0%  Max levels:  4
 Total:    Keyblocks used:   9%  Packed:   17%
 - check records and index references
 [LOTS OF ROW NUMBERS DELETED]
 Records:          1403698    M.recordlength:     226   Packed:             0%
 Recordspace used:     100%   Empty space:          0%  Blocks/Record:   1.00
 Record blocks:    1403698    Delete blocks:        0
 Recorddata:     317235748    Deleted data:         0
 Lost space:             0    Linkdata:             0
 User time 1639.63, System time 251.61
 Maximum resident set size 0, Integral resident set size 0
 Non physical pagefaults 0, Physical pagefaults 10580, Swaps 0
 Blocks in 4 out 0, Messages in 0 out 0, Signals 0
 Voluntary context switches 10604, Involuntary context switches 122798
 

Here are the sizes of the data and index files for the table used in the preceding examples:

-rw-rw-r--   1 monty    tcx     317235748 Jan 12 17:30 company.MYD
-rw-rw-r--   1 davida   tcx      96482304 Jan 12 18:35 company.MYM

Explanations for the types of information myisamchk produces are given here. The ``keyfile'' is the index file. ``Record'' and ``row'' are synonymous:

If a table has been compressed with myisampack, myisamchk -d prints additional information about each table column. See myisampack, for an example of this information and a description of what it means.