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FBMYSQLCHECKFR(1)
NAME
mysqlcheck - a table maintenance and repair program
SYNOPSIS
mysqlcheck [options] [db_name [tbl_name ...]]
DESCRIPTION
The mysqlcheck client checks, repairs, optimizes, and analyzes tables.
mysqlcheck is similar in function to myisamchk, but works differently. The
main operational difference is that mysqlcheck must be used when the mysqld
server is running, whereas myisamchk should be used when it is not. The
benefit of using mysqlcheck is that you do not have to stop the server to
check or repair your tables.
mysqlcheck uses the SQL statements CHECK TABLE, REPAIR TABLE, ANALYZE
TABLE, and OPTIMIZE TABLE in a convenient way for the user. It determines
which statements to use for the operation you want to perform, and then
sends the statements to the server to be executed. For details about which
storage engines each statement works with, see the descriptions for those
statements in Chapter 13, SQL Statement Syntax.
The MyISAM storage engine supports all four statements, so mysqlcheck can
be used to perform all four operations on MyISAM tables. Other storage
engines do not necessarily support all operations. In such cases, an error
message is displayed. For example, if test.t is a MEMORY table, an attempt
to check it produces this result:
shell> mysqlcheck test t
test.t
note : The storage engine for the table doesn't support check
There are three general ways to invoke mysqlcheck:
shell> mysqlcheck [options] db_name [tables]
shell> mysqlcheck [options] --databases db_name1 [db_name2 db_name3...]
shell> mysqlcheck [options] --all-databases
If you do not name any tables following db_name or if you use the
--databases or --all-databases option, entire databases are checked.
mysqlcheck has a special feature compared to other client programs. The
default behavior of checking tables (--check) can be changed by renaming
the binary. If you want to have a tool that repairs tables by default, you
should just make a copy of mysqlcheck named mysqlrepair, or make a symbolic
link to mysqlcheck named mysqlrepair. If you invoke mysqlrepair, it repairs
tables.
The following names can be used to change mysqlcheck default behavior:
mysqlrepairThe default option is --repairmysqlanalyzeThe default option is
--analyzemysqloptimizeThe default option is --optimize.PP mysqlcheck
supports the following options:
· --help, -?
Display a help message and exit.
· --all-databases, -A
Check all tables in all databases. This is the same as using the
--databases option and naming all the databases on the command line.
· --all-in-1, -1
Instead of issuing a statement for each table, execute a single
statement for each database that names all the tables from that database
to be processed.
· --analyze, -a
Analyze the tables.
· --auto-repair
If a checked table is corrupted, automatically fix it. Any necessary
repairs are done after all tables have been checked.
· --character-sets-dir=path
The directory where character sets are installed. See Section 9.1, The
Character Set Used for Data and Sorting.
· --check, -c
Check the tables for errors. This is the default operation.
· --check-only-changed, -C
Check only tables that have changed since the last check or that have
not been closed properly.
· --check-upgrade, -g
Invoke CHECK TABLE with the FOR UPGRADE option to check tables for
incompatibilities with the current version of the server. This option
was added in MySQL 5.0.19.
· --compress
Compress all information sent between the client and the server if both
support compression.
· --databases, -B
Process all tables in the named databases. Normally, mysqlcheck treats
the first name argument on the command line as a database name and
following names as table names. With this option, it treats all name
arguments as database names.
· --debug[=debug_options], -# [debug_options]
Write a debugging log. A typical debug_options string is often
'd:t:o,file_name'.
· --default-character-set=charset_name
Use charset_name as the default character set. See Section 9.1, The
Character Set Used for Data and Sorting.
· --extended, -e
If you are using this option to check tables, it ensures that they are
100% consistent but takes a long time.
If you are using this option to repair tables, it runs an extended
repair that may not only take a long time to execute, but may produce a
lot of garbage rows also!
· --fast, -F
Check only tables that have not been closed properly.
· --force, -f
Continue even if an SQL error occurs.
· --host=host_name, -h host_name
Connect to the MySQL server on the given host.
· --medium-check, -m
Do a check that is faster than an --extended operation. This finds only
99.99% of all errors, which should be good enough in most cases.
· --optimize, -o
Optimize the tables.
· --password[=password], -p[password]
The password to use when connecting to the server. If you use the short
option form (-p), you cannot have a space between the option and the
password. If you omit the password value following the --password or -p
option on the command line, you are prompted for one.
Specifying a password on the command line should be considered insecure.
See Section 7.6, Keeping Your Password Secure.
· --port=port_num, -P port_num
The TCP/IP port number to use for the connection.
· --protocol={TCP|SOCKET|PIPE|MEMORY}
The connection protocol to use.
· --quick, -q
If you are using this option to check tables, it prevents the check from
scanning the rows to check for incorrect links. This is the fastest
check method.
If you are using this option to repair tables, it tries to repair only
the index tree. This is the fastest repair method.
· --repair, -r
Perform a repair that can fix almost anything except unique keys that
are not unique.
· --silent, -s
Silent mode. Print only error messages.
· --socket=path, -S path
For connections to localhost, the Unix socket file to use, or, on
Windows, the name of the named pipe to use.
· --ssl*
Options that begin with --ssl specify whether to connect to the server
via SSL and indicate where to find SSL keys and certificates. See
Section 7.7.3, SSL Command Options.
· --tables
Overrides the --databases or -B option. All name arguments following the
option are regarded as table names.
· --use-frm
For repair operations on MyISAM tables, get the table structure from the
.frm file so that the table can be repaired even if the .MYI header is
corrupted.
· --user=user_name, -u user_name
The MySQL username to use when connecting to the server.
· --verbose, -v
Verbose mode. Print information about the various stages of program
operation.
· --version, -V
Display version information and exit.
SEE ALSO
msql2mysql(1), myisam_ftdump(1), myisamchk(1), myisamlog(1), myisampack(1),
mysql(1), mysql.server(1), mysql_config(1), mysql_fix_privilege_tables(1),
mysql_upgrade(1), mysql_zap(1), mysqlaccess(1), mysqladmin(1),
mysqlbinlog(1), mysqld(1), mysqld_multi(1), mysqld_safe(1), mysqldump(1),
mysqlhotcopy(1), mysqlimport(1), mysqlmanager(1), mysqlshow(1), perror(1),
replace(1), safe_mysqld(1)
For more information, please refer to the MySQL Reference Manual, which may
already be installed locally and which is also available online at
http://dev.mysql.com/doc/.
AUTHOR
MySQL AB (http://www.mysql.com/). This software comes with no warranty.
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