The most significant N  bytes in the value are always 0 and are not stored. 

• no zeros 

Do not store zeros. 

• always zero 

Zero values are stored using one bit. 

• Huff tree 

The number of the Huffman tree associated with the column. 

• Bits 

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: 

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) 

myisamchk -eiv  output includes the following information: 

• Data records 

The number of rows in the table. 

• Deleted blocks 

