All MySQL clients that communicate with the server using the
mysqlclient
library use the following environment variables:
Name | Description |
MYSQL_UNIX_PORT | The default socket. Used with 'localhost'. |
MYSQL_TCP_PORT | The default TCP port. |
MYSQL_PWD | The default password. |
mysql
mysqlaccess
mysqladmin
mysqld
mysqldump
mysqlimport
LOAD DATA INFILE
. See section LOAD DATA INFILE syntax
mysqlshow
mysqlbug
mysql_install_db
isamchk
make_binary_release
msql2mysql
mSQL
program to
MySQL. Doesn't handle all cases but gives a good start when
converting.
replace
replace a
b b a -- files
swaps a
and b
in the given files.
safe_mysqld
For information about how to use isamchk to repair a crashed table: See section How to repair tables..
isamchk
doesn't use any more memory than you define with
the -O
options. The default is to use only about 2M to fix
things.
But isamchk
uses temporary files in TMPDIR
. If
TMPDIR
points to a memory file system you may easily get out of
memory errors.
Using -O sortbuffer=16M
should probably be enough for most cases.
To get a description/statistics from a table use the methods below. We will explain some of the information in more detail later.
isamchk -d table_name
--skip-locking
isamchk
may report an error for a table that is updated while
isamchk runs, but there isn't any risk of destroying data.
isamchk -d -v table_name
isamchk -eis table_name
isamchk -eiv table_name
Example of isamchk -d
output:
ISAM file: company.ISM Data records: 1403698 Deleted blocks: 0 Recordlength: 226 Record format: Fixed length 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 isamchk -d -v
output:
ISAM file: company.ISM Isam-version: 2 Creation time: 1996-08-28 11:44:22 Recover time: 1997-01-12 18:35:29 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 Record format: Fixed length r table description: Key Start Len Index Type Root Blocksize Rec/key 1 2 8 unique double 15845376 1024 1 2 15 10 multip. text packed stripped 25062400 1024 2 3 219 8 multip. double 40907776 1024 73 4 63 10 multip. text packed stripped 48097280 1024 5 5 167 2 multip. unsigned short 55200768 1024 4840 6 177 4 multip. unsigned long 65145856 1024 1346 7 155 4 multip. text 75090944 1024 4995 8 138 4 multip. unsigned long 85036032 1024 87 9 177 4 multip. unsigned long 96481280 1024 178 193 1 text
Example of isamchk -eis
output:
Checking ISAM file: company.ISM 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 Recordblocks: 1403698 Deleteblocks: 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 contexts switches 639, Involuntary contexts switches 28966
Example of isamchk -eiv
output:
Checking ISAM file: company.ISM Data records: 1403698 Deleted blocks: 0 - check file-size - check delete-chain 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 Recordblocks: 1403698 Deleteblocks: 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 contexts switches 10604, Involuntary contexts switches 122798
Here are the data file sizes of the table used above.
-rw-rw-r-- 1 monty tcx 317235748 Jan 12 17:30 company.ISD -rw-rw-r-- 1 davida tcx 96482304 Jan 12 18:35 company.ISM
Explanations for the things isamchk
prints:
ISAM file
Isam-version
Creation time
Recover time
Data records
Deleted blocks
Datafile: Parts
Data
records
.
Deleted data
Datafile pointer
Keyfile pointer
Max datafile length
.ISD
) get.
Max keyfile length
.ISM
) get.
Recordlength
Record format
Fixed
length
.
table description
Key
Start
Len
Index
unique
or multip.
. If one value can exist multiple times
in this index.
Type
C
data-type
with the options packed, stripped or empty.
Root
Blocksize
Rec/key
isamchk -a
. If this is not updated at all, a default
value of 30 is given.
Keyblocks used
Packed
CHAR
/VARCHAR
/DECIMAL
keys. For long strings like
names, this can significantly reduce the space used. In the above example
the 4 key is 10 characters long and gets a 60% reduction in space.
Max levels
Records
M.recordlength
Packed
Recordspace used
Empty space
Blocks/Record
isamchk
. See section How to repair tables..
Recordblocks
Deleteblocks
Recorddata
Deleted data
Lost space
Linkdata
pack_isam
is an extra that you get when ordering more that 10
licenses or extended support. Since pack_isam
is distributed
binary only, pack_isam
is only available on some platforms.
Of course, all future updates to pack_isam
is included in the
price. pack_isam
may at some time be included as standard when
we get some kind of turnover for MySQL.
pack_isam
works by compressing each column in the table
separately. The information needed to decompress is read into memory
when the table is opened. This gives a much better performance when
accessing individual records as one only has to uncompress exactly one
record, not a much larger disk block like when using Stacker on MSDOS.
MySQL uses memory mapping (mmap) on compressed tables and falls back to normal read/write file usage if mmap doesn't work.
Usually, pack_isam
packs the datafile 40-70%.
There is currently two limitations with pack_isam
:
Fixing these limitations is on our TODO but with low priority.
pack_isam
options:
> pack_isam --help pack_isam Ver 5.0 for SOLARIS 2.5 on SPARCstation Copyright (C) 1994-1997 TcX AB & Monty Program KB & Detron HB. This is not free software. You must have a license to use this program This software comes with ABSOLUTELY NO WARRANTY Pack a ISAM-database to take much smaller space Keys are not updated, one must run isamchk -rq on datafile afterwards Usage: pack_isam [OPTIONS] -b, --backup Make a backup of the table as table_name.OLD -f, --force Force packing of table even if it's gets bigger or tempfile exists. -j, --join=# Join all given tables into table. All tables MUST be identical. -p, --packlength=# Force storage size of recordlength (1,2 or 3) -s, --silent Be more silent. -t, --test Don't pack table only test packing it -v, --verbose Write info about progress and packing result -w, --wait Wait and retry if table is in use -T, --tmp_dir=# Use temporary directory to store temporary table -#, --debug=... output debug log. Often this is 'd:t:o,filename` -?, --help display this help and exit -V, --version output version information and exit
Typical run:
(/my/monty/tmp) ls -l station.* -rw-rw-r-- 1 monty my 994128 Apr 17 19:00 station.ISD -rw-rw-r-- 1 monty my 53248 Apr 17 19:00 station.ISM -rw-rw-r-- 1 monty my 5767 Apr 17 19:00 station.frm (/my/monty/tmp) isamchk -dvv station ISAM file: station Isam-version: 2 Creation time: 1996-03-13 10:08:58 Recover time: 1997-02-02 3:06:43 Data records: 1192 Deleted blocks: 0 Datafile: Parts: 1192 Deleted data: 0 Datafilepointer (bytes): 2 Keyfile pointer (bytes): 2 Max datafile length: 54657023 Max keyfile length: 33554431 Recordlength: 834 Record format: Fixed length table description: Key Start Len Index Type Root Blocksize Rec/key 1 2 4 unique unsigned long 1024 1024 1 2 32 30 multip. text 10240 1024 1 column Start Length Type 1 1 1 2 2 4 3 6 4 4 10 1 5 11 20 6 31 1 7 32 30 8 62 35 9 97 35 10 132 35 11 167 4 12 171 16 13 187 35 14 222 4 15 226 16 16 242 20 17 262 20 18 282 20 19 302 30 20 332 4 21 336 4 22 340 1 23 341 8 24 349 8 25 357 8 26 365 2 27 367 2 28 369 4 29 373 4 30 377 1 31 378 2 32 380 8 33 388 4 34 392 4 35 396 4 36 400 4 37 404 1 38 405 4 39 409 4 40 413 4 41 417 4 42 421 4 43 425 4 44 429 20 45 449 30 46 479 1 47 480 1 48 481 79 49 560 79 50 639 79 51 718 79 52 797 8 53 805 1 54 806 1 55 807 20 56 827 4 57 831 4 Compressing station.ISD: (1192 records) - Calculating statistics normal: 20 empty-space: 16 empty-zero: 12 empty-fill: 11 pre-space: 0 end-space: 12 intervall-fields: 5 zero: 7 Original trees: 57 After join: 17 - Compressing file 87.14% (/my/monty/tmp) ls -l station.* -rw-rw-r-- 1 monty my 127874 Apr 17 19:00 station.ISD -rw-rw-r-- 1 monty my 55296 Apr 17 19:04 station.ISM -rw-rw-r-- 1 monty my 5767 Apr 17 19:00 station.frm (my/monty/tmp) isamchk -dvv station ISAM file: station Isam-version: 2 Creation time: 1996-03-13 10:08:58 Recover time: 1997-04-17 19:04:26 Data records: 1192 Deleted blocks: 0 Datafile: Parts: 1192 Deleted data: 0 Datafilepointer (bytes): 3 Keyfile pointer (bytes): 1 Max datafile length: 16777215 Max keyfile length: 131071 Recordlength: 834 Record format: Compressed table description: Key Start Len Index Type Root Blocksize Rec/key 1 2 4 unique unsigned long 10240 1024 1 2 32 30 multip. text 54272 1024 1 Field Start Length Type Huff tree Bits 1 1 1 constant 1 0 2 2 4 zerofill(1) 2 9 3 6 4 no zeros, zerofill(1) 2 9 4 10 1 3 9 5 11 20 table-lockup 4 0 6 31 1 3 9 7 32 30 no endspace, not_always 5 9 8 62 35 no endspace, not_always, no empty 6 9 9 97 35 no empty 7 9 10 132 35 no endspace, not_always, no empty 6 9 11 167 4 zerofill(1) 2 9 12 171 16 no endspace, not_always, no empty 5 9 13 187 35 no endspace, not_always, no empty 6 9 14 222 4 zerofill(1) 2 9 15 226 16 no endspace, not_always, no empty 5 9 16 242 20 no endspace, not_always 8 9 17 262 20 no endspace, no empty 8 9 18 282 20 no endspace, no empty 5 9 19 302 30 no endspace, no empty 6 9 20 332 4 allways zero 2 9 21 336 4 allways zero 2 9 22 340 1 3 9 23 341 8 table-lockup 9 0 24 349 8 table-lockup 10 0 25 357 8 allways zero 2 9 26 365 2 2 9 27 367 2 no zeros, zerofill(1) 2 9 28 369 4 no zeros, zerofill(1) 2 9 29 373 4 table-lockup 11 0 30 377 1 3 9 31 378 2 no zeros, zerofill(1) 2 9 32 380 8 no zeros 2 9 33 388 4 allways zero 2 9 34 392 4 table-lockup 12 0 35 396 4 no zeros, zerofill(1) 13 9 36 400 4 no zeros, zerofill(1) 2 9 37 404 1 2 9 38 405 4 no zeros 2 9 39 409 4 allways zero 2 9 40 413 4 no zeros 2 9 41 417 4 allways zero 2 9 42 421 4 no zeros 2 9 43 425 4 allways zero 2 9 44 429 20 no empty 3 9 45 449 30 no empty 3 9 46 479 1 14 4 47 480 1 14 4 48 481 79 no endspace, no empty 15 9 49 560 79 no empty 2 9 50 639 79 no empty 2 9 51 718 79 no endspace 16 9 52 797 8 no empty 2 9 53 805 1 17 1 54 806 1 3 9 55 807 20 no empty 3 9 56 827 4 no zeros, zerofill(2) 2 9 57 831 4 no zeros, zerofill(1) 2 9
Go to the first, previous, next, last section, table of contents.