myisamchk — MyISAM Table-Maintenance Utility The most significant  N  bytes in the value are always 0 and are not stored. Do not store zeros. Zero values are stored using one bit. The number of the Huffman tree associated with the column. The number of bits used in the Huffman tree. The  Huff tree  and  Bits  fields are displayed if the table has been compressed with  myisampack . See Section 4.6.6, “myisampack — Generate Compressed, Read-Only MyISAM Tables” , for an example of this information. Example of  myisamchk -eiv  output: myisamchk -eiv  output includes the following information: The number of rows in the table. 576 • Deleted blocks • Data records • Bits • Huff tree • always zero • no zeros Checking MyISAM file: person Data records: 306688 Deleted blocks: 0 - check file-size - check record delete-chain No recordlinks - check key delete-chain block_size 1024: - check index reference - check data record references index: 1 Key: 1: Keyblocks used: 98% Packed: 0% Max levels: 3 - check data record references index: 2 Key: 2: Keyblocks used: 99% Packed: 97% Max levels: 3 - check data record references index: 3 Key: 3: Keyblocks used: 98% Packed: -14% Max levels: 3 Total: Keyblocks used: 98% Packed: 89% - check records and index references *** LOTS OF ROW NUMBERS DELETED *** Records: 306688 M.recordlength: 25 Packed: 83% Recordspace used: 97% Empty space: 2% Blocks/Record: 1.00 Record blocks: 306688 Delete blocks: 0 Record data: 7934464 Deleted data: 0 Lost space: 256512 Linkdata: 1156096 User time 43.08, System time 1.68 Maximum resident set size 0, Integral resident set size 0 Non-physical pagefaults 0, Physical pagefaults 0, Swaps 0 Blocks in 0 out 7, Messages in 0 out 0, Signals 0 Voluntary context switches 0, Involuntary context switches 0 Maximum memory usage: 1046926 bytes (1023k)