Oracle 5.0 Reference Manual page 352

•
Recordblocks
How many blocks (links) are used. For fixed-format tables, this is the same as the number of rows.
•
Deleteblocks
How many blocks (links) are deleted.
•
Recorddata
How many bytes in the data file are used.
•
Deleted data
How many bytes in the data file are deleted (unused).
•
Lost space
If a row is updated to a shorter length, some space is lost. This is the sum of all such losses, in
bytes.
•
Linkdata
When the dynamic table format is used, row fragments are linked with pointers (4 to 7 bytes each).
Linkdata
4.6.3.6.
myisamchk
Memory allocation is important when you run myisamchk.
its memory-related variables are set to. If you are going to use
should first decide how much memory you want it to use. The default is to use only about 3MB to
perform repairs. By using larger values, you can get
have more than 512MB RAM available, you could use options such as these (in addition to any other
options you might specify):
shell> myisamchk --sort_buffer_size=256M \
Using
--sort_buffer_size=16M
Be aware that
system, out of memory errors can easily occur. If this happens, run
tmpdir=path
When performing repair operations,
• Twice the size of the data file (the original file and a copy). This space is not needed if you do a
repair with
available on the same file system as the original data file, as the copy is created in the same
directory as the original.
• Space for the new index file that replaces the old one. The old index file is truncated at the start of
the repair operation, so you usually ignore this space. This space must be available on the same file
system as the original data file.
• When using
recover
directory (specified by
of space required:
(largest_key
— MyISAM Table-Maintenance Utility
myisamchk
is the sum of the amount of storage used by all such pointers.
Memory Usage
--key_buffer_size=512M \
--read_buffer_size=64M \
--write_buffer_size=64M ...
uses temporary files in TMPDIR. If
myisamchk
[325] option to specify a directory located on a file system that has more space.
[324]; in this case, only the index file is re-created. This space must be
--quick
[324] or
--recover
[324]), you need space on disk for sorting. This space is allocated in the temporary
or
TMPDIR
+ row_pointer_length) *
myisamchk
is probably enough for most cases.
also needs a lot of disk space:
myisamchk
[325]
--sort-recover
[325]). The following formula yields the amount
--tmpdir=path
number_of_rows
332
uses no more memory than
myisamchk
on very large tables, you
myisamchk
to operate faster. For example, if you
points to a memory file
TMPDIR
with the
myisamchk
(but not when using
* 2
--
--safe-