REPAIR [NO_WRITE_TO_BINLOG | LOCAL] TABLE
tbl_name [, tbl_name] ...
[QUICK] [EXTENDED] [USE_FRM]
REPAIR TABLE repairs a possibly
corrupted table. By default, it has the same effect as
myisamchk --recover
tbl_name.
REPAIR TABLE works for
MyISAM and for ARCHIVE
tables. See Section 13.1, “The MyISAM Storage Engine”, and
Section 13.8, “The ARCHIVE Storage Engine”.
This statement requires SELECT
and INSERT privileges for the
table.
Normally, you should never have to run this statement. However,
if disaster strikes, REPAIR TABLE
is very likely to get back all your data from a
MyISAM table. If your tables become corrupted
often, you should try to find the reason for it, to eliminate
the need to use REPAIR TABLE. See
Section B.5.4.2, “What to Do If MySQL Keeps Crashing”, and
Section 13.1.4, “MyISAM Table Problems”.
Caution
It is best to make a backup of a table before performing a table repair operation; under some circumstances the operation might cause data loss. Possible causes include but are not limited to file system errors.
Warning
If the server dies during a REPAIR
TABLE operation, it is essential after restarting it
that you immediately execute another
REPAIR TABLE statement for the
table before performing any other operations on it. In the
worst case, you might have a new clean index file without
information about the data file, and then the next operation
you perform could overwrite the data file. This is an unlikely
but possible scenario that underscores the value of making a
backup first.
REPAIR TABLE returns a result set
with the following columns.
| Column | Value |
Table |
The table name |
Op |
Always repair
|
Msg_type |
status, error,
info, or warning
|
Msg_text |
An informational message |
The REPAIR TABLE statement might
produce many rows of information for each repaired table. The
last row has a Msg_type value of
status and Msg_test
normally should be OK. If you do not get
OK for a MyISAM table, you
should try repairing it with myisamchk
--safe-recover. (REPAIR
TABLE does not implement all the options of
myisamchk.) With myisamchk
--safe-recover, you can also use options that
REPAIR TABLE does not support,
such as --max-record-length.
If you use the QUICK option,
REPAIR TABLE tries to repair only
the index file, and not the data file. This type of repair is
like that done by myisamchk --recover
--quick.
If you use the EXTENDED option, MySQL creates
the index row by row instead of creating one index at a time
with sorting. This type of repair is like that done by
myisamchk --safe-recover.
The USE_FRM option is available for use if
the .MYI index file is missing or if its
header is corrupted. This option tells MySQL not to trust the
information in the .MYI file header and to
re-create it using information from the
.frm file. This kind of repair cannot be
done with myisamchk.
Note
Use the USE_FRM option
only if you cannot use regular
REPAIR modes! Telling the server to ignore
the .MYI file makes important table
metadata stored in the .MYI unavailable
to the repair process, which can have deleterious
consequences:
The current
AUTO_INCREMENTvalue is lost.The link to deleted records in the table is lost, which means that free space for deleted records will remain unoccupied thereafter.
The
.MYIheader indicates whether the table is compressed. If the server ignores this information, it cannot tell that a table is compressed and repair can cause change or loss of table contents. This means thatUSE_FRMshould not be used with compressed tables. That should not be necessary, anyway: Compressed tables are read only, so they should not become corrupt.
Caution
As of MySQL 5.0.62, if you use USE_FRM for
a table that was created by a different version of the MySQL
server than the one you are currently running,
REPAIR TABLE will not attempt
to repair the table. In this case, the result set returned by
REPAIR TABLE contains a line
with a Msg_type value of
error and a Msg_text
value of Failed repairing incompatible .FRM
file.
Prior to MySQL 5.0.62, do not use
USE_FRM if your table was created by a
different version of the MySQL server. Doing so risks the loss
of all rows in the table. It is particularly dangerous to use
USE_FRM after the server returns this
message:
Table upgrade required. Please do
"REPAIR TABLE `tbl_name`" to fix it!
If USE_FRM is not used,
REPAIR TABLE checks the table to
see whether an upgrade is required. If so, it performs the
upgrade, following the same rules as
CHECK TABLE ... FOR
UPGRADE. See Section 12.4.2.3, “CHECK TABLE Syntax”, for more
information. As of MySQL 5.0.62, REPAIR
TABLE without USE_FRM upgrades the
.frm file to the current version.
By default, REPAIR TABLE
statements are written to the binary log so that they will be
replicated to replication slaves. Logging can be suppressed with
the optional NO_WRITE_TO_BINLOG keyword or
its alias LOCAL.
User Comments
false positive case after upgrade
the character sets dir configuration was missing and no tables repair was needed.
i had a strange issue.
i had upgraded mysql from public repository with apt-get
and after then had disk full error and had to restart.
after repairing the disk full error i have discovered the data selected from tables is gibberish.
in phpmyadmin the type of all tables was VIEW
and they all ware corrupt even if i repair them or optimize or check... and when i repair it with myisamchk it does nothing.
just shows :
myisamchk -eron emaillist, the errors:
- recovering (with sort) MyISAM-table 'emaillist'
Data records: 4255
- Fixing index 1
Found link that points at -1735598930481103523 (outside data file) at 27888
Found block that points outside data file at 268252
Found block that points outside data file at 268572
Found block that points outside data file at 268844
Found block that points outside data file at 268916
and nothing was changed after the repair.
in phpmyadmin when i click on a table it selected SHOW FULL COLUMNS and it showd an error similar to: the table is corrupt unknown COLLATIONS #16 error #1273
i have started to search, where are those collation numbers came from, and found that in mysql schema database there is a collations table
and my number 16 was missing
and i saw that the list is suspiciously small.
when i ran 'mysql --help' there was no charset directory
the solution was to set the in my.cnf
[mysqld]
character-sets-dir=/usr/share/mysql/charsets
and it worked like a charm
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