1MYSQLCHECK(1) MySQL Database System MYSQLCHECK(1)
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6 mysqlcheck - a table maintenance program
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9 mysqlcheck [options] [db_name [tbl_name ...]]
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12 The mysqlcheck client performs table maintenance: It checks, repairs,
13 optimizes, or analyzes tables.
14 Each table is locked and therefore unavailable to other sessions while
16 it is being processed, although for check operations, the table is
17 locked with a READ lock only (see Section 13.3.5, “LOCK TABLES and
18 UNLOCK TABLES Syntax”, for more information about READ and WRITE
19 locks). Table maintenance operations can be time-consuming,
20 particularly for large tables. If you use the --databases or
21 --all-databases option to process all tables in one or more databases,
22 an invocation of mysqlcheck might take a long time. (This is also true
23 for mysql_upgrade because that program invokes mysqlcheck to check all
24 tables and repair them if necessary.)
25 mysqlcheck is similar in function to myisamchk, but works differently.
27 The main operational difference is that mysqlcheck must be used when
28 the mysqld server is running, whereas myisamchk should be used when it
29 is not. The benefit of using mysqlcheck is that you do not have to stop
30 the server to perform table maintenance.
31 mysqlcheck uses the SQL statements CHECK TABLE, REPAIR TABLE, ANALYZE
33 TABLE, and OPTIMIZE TABLE in a convenient way for the user. It
34 determines which statements to use for the operation you want to
35 perform, and then sends the statements to the server to be executed.
36 For details about which storage engines each statement works with, see
37 the descriptions for those statements in Section 13.7.2, “Table
38 Maintenance Statements”.
39 The MyISAM storage engine supports all four maintenance operations, so
41 mysqlcheck can be used to perform any of them on MyISAM tables. Other
42 storage engines do not necessarily support all operations. In such
43 cases, an error message is displayed. For example, if test.t is a
44 MEMORY table, an attempt to check it produces this result:
45 shell> mysqlcheck test t
47 test.t
48 note : The storage engine for the table doesn't support check
49 If mysqlcheck is unable to repair a table, see Section 2.13.4,
51 “Rebuilding or Repairing Tables or Indexes” for manual table repair
52 strategies. This will be the case, for example, for InnoDB tables,
53 which can be checked with CHECK TABLE, but not repaired with REPAIR
54 TABLE.
55 The use of mysqlcheck with partitioned tables is not supported before
57 MySQL 5.1.27.
58 Caution
60 It is best to make a backup of a table before performing a table
61 repair operation; under some circumstances the operation might
62 cause data loss. Possible causes include but are not limited to
63 file system errors.
64 There are three general ways to invoke mysqlcheck:
66 shell> mysqlcheck [options] db_name [tbl_name ...]
68 shell> mysqlcheck [options] --databases db_name ...
69 shell> mysqlcheck [options] --all-databases
70 If you do not name any tables following db_name or if you use the
72 --databases or --all-databases option, entire databases are checked.
73 mysqlcheck has a special feature compared to other client programs. The
75 default behavior of checking tables (--check) can be changed by
76 renaming the binary. If you want to have a tool that repairs tables by
77 default, you should just make a copy of mysqlcheck named mysqlrepair,
78 or make a symbolic link to mysqlcheck named mysqlrepair. If you invoke
79 mysqlrepair, it repairs tables.
80 The names shown in the following table can be used to change mysqlcheck
82 default behavior.
83 ┌──────────────┬───────────────────────┐
85 │Command │ Meaning │
86 ├──────────────┼───────────────────────┤
87 │mysqlrepair │ The default option is │
88 │ │ --repair │
89 ├──────────────┼───────────────────────┤
90 │mysqlanalyze │ The default option is │
91 │ │ --analyze │
92 ├──────────────┼───────────────────────┤
93 │mysqloptimize │ The default option is │
94 │ │ --optimize │
95 └──────────────┴───────────────────────┘
96 mysqlcheck supports the following options, which can be specified on
98 the command line or in the [mysqlcheck] and [client] groups of an
99 option file. mysqlcheck also supports the options for processing
100 option files described at Section 4.2.3.4, “Command-Line Options that
101 Affect Option-File Handling”.
102 · --help, -?
104 Display a help message and exit.
106 · --all-databases, -A
108 Check all tables in all databases. This is the same as using the
110 --databases option and naming all the databases on the command
111 line.
112 · --all-in-1, -1
114 Instead of issuing a statement for each table, execute a single
116 statement for each database that names all the tables from that
117 database to be processed.
118 · --analyze, -a
120 Analyze the tables.
122 · --auto-repair
124 If a checked table is corrupted, automatically fix it. Any
126 necessary repairs are done after all tables have been checked.
127 · --bind-address=ip_address
129 On a computer having multiple network interfaces, this option can
131 be used to select which interface is employed when connecting to
132 the MySQL server.
133 This option is supported only in the version of mysqlcheck that is
135 supplied with MySQL Cluster, beginning with MySQL Cluster NDB
136 6.3.4. It is not available in standard MySQL 5.1 releases.
137 · --character-sets-dir=path
139 The directory where character sets are installed. See Section 10.5,
141 “Character Set Configuration”.
142 · --check, -c
144 Check the tables for errors. This is the default operation.
146 · --check-only-changed, -C
148 Check only tables that have changed since the last check or that
150 have not been closed properly.
151 · --check-upgrade, -g
153 Invoke CHECK TABLE with the FOR UPGRADE option to check tables for
155 incompatibilities with the current version of the server. This
156 option automatically enables the --fix-db-names and
157 --fix-table-names options. --check-upgrade was added in MySQL
158 5.1.7.
159 · --compress
161 Compress all information sent between the client and the server if
163 both support compression.
164 · --databases, -B
166 Process all tables in the named databases. Normally, mysqlcheck
168 treats the first name argument on the command line as a database
169 name and following names as table names. With this option, it
170 treats all name arguments as database names.
171 · --debug[=debug_options], -# [debug_options]
173 Write a debugging log. A typical debug_options string is
175 'd:t:o,file_name'. The default is 'd:t:o'.
176 · --debug-check
178 Print some debugging information when the program exits. This
180 option was added in MySQL 5.1.21.
181 · --debug-info
183 Print debugging information and memory and CPU usage statistics
185 when the program exits. This option was added in MySQL 5.1.14.
186 · --default-character-set=charset_name
188 Use charset_name as the default character set. See Section 10.5,
190 “Character Set Configuration”.
191 · --extended, -e
193 If you are using this option to check tables, it ensures that they
195 are 100% consistent but takes a long time.
196 If you are using this option to repair tables, it runs an extended
198 repair that may not only take a long time to execute, but may
199 produce a lot of garbage rows also!
200 · --fast, -F
202 Check only tables that have not been closed properly.
204 · --fix-db-names
206 Convert database names to 5.1 format. Only database names that
208 contain special characters are affected. This option was added in
209 MySQL 5.1.7.
210 · --fix-table-names
212 Convert table names to 5.1 format. Only table names that contain
214 special characters are affected. This option was added in MySQL
215 5.1.7. As of MySQL 5.1.23, this option also applies to views.
216 · --force, -f
218 Continue even if an SQL error occurs.
220 · --host=host_name, -h host_name
222 Connect to the MySQL server on the given host.
224 · --medium-check, -m
226 Do a check that is faster than an --extended operation. This finds
228 only 99.99% of all errors, which should be good enough in most
229 cases.
230 · --optimize, -o
232 Optimize the tables.
234 · --password[=password], -p[password]
236 The password to use when connecting to the server. If you use the
238 short option form (-p), you cannot have a space between the option
239 and the password. If you omit the password value following the
240 --password or -p option on the command line, mysqlcheck prompts for
241 one.
242 Specifying a password on the command line should be considered
244 insecure. See Section 6.1.2.1, “End-User Guidelines for Password
245 Security”. You can use an option file to avoid giving the password
246 on the command line.
247 · --pipe, -W
249 On Windows, connect to the server using a named pipe. This option
251 applies only if the server supports named-pipe connections.
252 · --port=port_num, -P port_num
254 The TCP/IP port number to use for the connection.
256 · --protocol={TCP|SOCKET|PIPE|MEMORY}
258 The connection protocol to use for connecting to the server. It is
260 useful when the other connection parameters normally would cause a
261 protocol to be used other than the one you want. For details on the
262 permissible values, see Section 4.2.2, “Connecting to the MySQL
263 Server”.
264 · --quick, -q
266 If you are using this option to check tables, it prevents the check
268 from scanning the rows to check for incorrect links. This is the
269 fastest check method.
270 If you are using this option to repair tables, it tries to repair
272 only the index tree. This is the fastest repair method.
273 · --repair, -r
275 Perform a repair that can fix almost anything except unique keys
277 that are not unique.
278 · --silent, -s
280 Silent mode. Print only error messages.
282 · --socket=path, -S path
284 For connections to localhost, the Unix socket file to use, or, on
286 Windows, the name of the named pipe to use.
287 · --ssl*
289 Options that begin with --ssl specify whether to connect to the
291 server using SSL and indicate where to find SSL keys and
292 certificates. See Section 6.3.6.4, “SSL Command Options”.
293 · --tables
295 Override the --databases or -B option. All name arguments following
297 the option are regarded as table names.
298 · --use-frm
300 For repair operations on MyISAM tables, get the table structure
302 from the .frm file so that the table can be repaired even if the
303 .MYI header is corrupted.
304 · --user=user_name, -u user_name
306 The MySQL user name to use when connecting to the server.
308 · --verbose, -v
310 Verbose mode. Print information about the various stages of program
312 operation.
313 · --version, -V
315 Display version information and exit.
317 · --write-binlog
319 This option is enabled by default, so that ANALYZE TABLE, OPTIMIZE
321 TABLE, and REPAIR TABLE statements generated by mysqlcheck are
322 written to the binary log. Use --skip-write-binlog to cause
323 NO_WRITE_TO_BINLOG to be added to the statements so that they are
324 not logged. Use the --skip-write-binlog when these statements
325 should not be sent to replication slaves or run when using the
326 binary logs for recovery from backup. This option was added in
327 MySQL 5.1.18.
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330 Copyright © 1997, 2013, Oracle and/or its affiliates. All rights
331 reserved.
332 This documentation is free software; you can redistribute it and/or
334 modify it only under the terms of the GNU General Public License as
335 published by the Free Software Foundation; version 2 of the License.
336 This documentation is distributed in the hope that it will be useful,
338 but WITHOUT ANY WARRANTY; without even the implied warranty of
339 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
340 General Public License for more details.
341 You should have received a copy of the GNU General Public License along
343 with the program; if not, write to the Free Software Foundation, Inc.,
344 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see
345 http://www.gnu.org/licenses/.
346
349 For more information, please refer to the MySQL Reference Manual, which
350 may already be installed locally and which is also available online at
351 http://dev.mysql.com/doc/.
352
354 Oracle Corporation (http://dev.mysql.com/).
355MySQL 5.1 11/04/2013 MYSQLCHECK(1)