Manual Reference Pages  - \FBMYSQLCHECK\FR (1)


.ds Aq ’

NAME

mysqlcheck - a table maintenance program

CONTENTS

SYNOPSIS

mysqlcheck [options] [db_name [tbl_name ...]]

DESCRIPTION

The mysqlcheck client performs table maintenance: It checks, repairs, optimizes, or analyzes tables.

Each table is locked and therefore unavailable to other sessions while it is being processed, although for check operations, the table is locked with a READ lock only (see Section 13.3.5, \(lqLOCK TABLES and UNLOCK TABLES Syntax\(rq, for more information about READ and WRITE locks). Table maintenance operations can be time-consuming, particularly for large tables. If you use the --databases or --all-databases option to process all tables in one or more databases, an invocation of mysqlcheck might take a long time. (This is also true for mysql_upgrade because that program invokes mysqlcheck to check all tables and repair them if necessary.)

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 perform table maintenance.

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 Section 13.7.2, \(lqTable Maintenance Statements\(rq.

The MyISAM storage engine supports all four maintenance operations, so mysqlcheck can be used to perform any of them 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 doesnt support check

If mysqlcheck is unable to repair a table, see Section 2.12.4, \(lqRebuilding or Repairing Tables or Indexes\(rq for manual table repair strategies. This will be the case, for example, for InnoDB tables, which can be checked with CHECK TABLE, but not repaired with REPAIR TABLE.

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.

There are three general ways to invoke mysqlcheck:

shell> mysqlcheck [options] db_name [tbl_name ...]
shell> mysqlcheck [options] --databases db_name ...
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 names shown in the following table can be used to change mysqlcheck default behavior.

Command Meaning
mysqlrepair The default option is --repair
mysqlanalyze The default option is --analyze
mysqloptimize The default option is --optimize

mysqlcheck supports the following options, which can be specified on the command line or in the [mysqlcheck] and [client] groups of an option file. mysqlcheck also supports the options for processing option files described at Section 4.2.3.4, \(lqCommand-Line Options that Affect Option-File Handling\(rq.

o

o --help, -?

Display a help message and exit.

o

o --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.

o

o --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.

o

o --analyze, -a

Analyze the tables.

o

o --auto-repair

If a checked table is corrupted, automatically fix it. Any necessary repairs are done after all tables have been checked.

o

o --bind-address=ip_address

On a computer having multiple network interfaces, this option can be used to select which interface is employed when connecting to the MySQL server.

This option is supported only in the version of mysqlcheck that is supplied with MySQL Cluster. It is not available in standard MySQL Server 5.5 releases.

o

o --character-sets-dir=path

The directory where character sets are installed. See Section 10.5, \(lqCharacter Set Configuration\(rq.

o

o --check, -c

Check the tables for errors. This is the default operation.

o

o --check-only-changed, -C

Check only tables that have changed since the last check or that have not been closed properly.

o

o --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 automatically enables the --fix-db-names and --fix-table-names options.

o

o --compress

Compress all information sent between the client and the server if both support compression.

o

o --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.

o

o --debug[=debug_options], -# [debug_options]

Write a debugging log. A typical debug_options string is d:t:o,file_name. The default is d:t:o.

o

o --debug-check

Print some debugging information when the program exits.

o

o --debug-info

Print debugging information and memory and CPU usage statistics when the program exits.

o

o --default-character-set=charset_name

Use charset_name as the default character set. See Section 10.5, \(lqCharacter Set Configuration\(rq.

o

o --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!

o

o --default-auth=plugin

The client-side authentication plugin to use. See Section 6.3.6, \(lqPluggable Authentication\(rq.

This option was added in MySQL 5.5.10.

o

o --fast, -F

Check only tables that have not been closed properly.

o

o --fix-db-names

Convert database names to 5.1 format. Only database names that contain special characters are affected.

o

o --fix-table-names

Convert table names to 5.1 format. Only table names that contain special characters are affected. This option also applies to views.

o

o --force, -f

Continue even if an SQL error occurs.

o

o --host=host_name, -h host_name

Connect to the MySQL server on the given host.

o

o --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.

o

o --optimize, -o

Optimize the tables.

o

o --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, mysqlcheck prompts for one.

Specifying a password on the command line should be considered insecure. See Section 6.1.2.1, \(lqEnd-User Guidelines for Password Security\(rq. You can use an option file to avoid giving the password on the command line.

o

o --pipe, -W

On Windows, connect to the server using a named pipe. This option applies only if the server supports named-pipe connections.

o

o --plugin-dir=path

The directory in which to look for plugins. It may be necessary to specify this option if the --default-auth option is used to specify an authentication plugin but mysqlcheck does not find it. See Section 6.3.6, \(lqPluggable Authentication\(rq.

This option was added in MySQL 5.5.10.

o

o --port=port_num, -P port_num

The TCP/IP port number to use for the connection.

o

o --protocol={TCP|SOCKET|PIPE|MEMORY}

The connection protocol to use for connecting to the server. It is useful when the other connection parameters normally would cause a protocol to be used other than the one you want. For details on the permissible values, see Section 4.2.2, \(lqConnecting to the MySQL Server\(rq.

o

o --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.

o

o --repair, -r

Perform a repair that can fix almost anything except unique keys that are not unique.

o

o --silent, -s

Silent mode. Print only error messages.

o

o --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.

o

o --ssl*

Options that begin with --ssl specify whether to connect to the server using SSL and indicate where to find SSL keys and certificates. See Section 6.3.8.4, \(lqSSL Command Options\(rq.

o

o --tables

Override the --databases or -B option. All name arguments following the option are regarded as table names.

o

o --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.

o

o --user=user_name, -u user_name

The MySQL user name to use when connecting to the server.

o

o --verbose, -v

Verbose mode. Print information about the various stages of program operation.

o

o --version, -V

Display version information and exit.

o

o --write-binlog

This option is enabled by default, so that ANALYZE TABLE, OPTIMIZE TABLE, and REPAIR TABLE statements generated by mysqlcheck are written to the binary log. Use --skip-write-binlog to cause NO_WRITE_TO_BINLOG to be added to the statements so that they are not logged. Use the --skip-write-binlog when these statements should not be sent to replication slaves or run when using the binary logs for recovery from backup.

COPYRIGHT

Copyright © 1997, 2013, Oracle and/or its affiliates. All rights reserved.

This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited.

The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing.

If this software or related documentation is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable:

U.S. GOVERNMENT RIGHTS Programs, software, databases, and related documentation and technical data delivered to U.S. Government customers are "commercial computer software" or "commercial technical data" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, duplication, disclosure, modification, and adaptation shall be subject to the restrictions and license terms set forth in the applicable Government contract, and, to the extent applicable by the terms of the Government contract, the additional rights set forth in FAR 52.227-19, Commercial Computer Software License (December 2007). Oracle USA, Inc., 500 Oracle Parkway, Redwood City, CA 94065.

This software is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications which may create a risk of personal injury. If you use this software in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure the safe use of this software. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software in dangerous applications.

Oracle is a registered trademark of Oracle Corporation and/or its affiliates. MySQL is a trademark of Oracle Corporation and/or its affiliates, and shall not be used without Oracle’s express written authorization. Other names may be trademarks of their respective owners.

This software and documentation may provide access to or information on content, products, and services from third parties. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to third-party content, products, and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred due to your access to or use of third-party content, products, or services.

This document in any form, software or printed matter, contains proprietary information that is the exclusive property of Oracle. Your access to and use of this material is subject to the terms and conditions of your Oracle Software License and Service Agreement, which has been executed and with which you agree to comply. This document and information contained herein may not be disclosed, copied, reproduced, or distributed to anyone outside Oracle without prior written consent of Oracle or as specifically provided below. This document is not part of your license agreement nor can it be incorporated into any contractual agreement with Oracle or its subsidiaries or affiliates.

This documentation is NOT distributed under a GPL license. Use of this documentation is subject to the following terms:

You may create a printed copy of this documentation solely for your own personal use. Conversion to other formats is allowed as long as the actual content is not altered or edited in any way. You shall not publish or distribute this documentation in any form or on any media, except if you distribute the documentation in a manner similar to how Oracle disseminates it (that is, electronically for download on a Web site with the software) or on a CD-ROM or similar medium, provided however that the documentation is disseminated together with the software on the same medium. Any other use, such as any dissemination of printed copies or use of this documentation, in whole or in part, in another publication, requires the prior written consent from an authorized representative of Oracle. Oracle and/or its affiliates reserve any and all rights to this documentation not expressly granted above.

For more information on the terms of this license, or for details on how the MySQL documentation is built and produced, please visit \m[blue]MySQL Contact & Questions\m[].

For additional licensing information, including licenses for third-party libraries used by MySQL products, see Preface and Legal Notices.

For help with using MySQL, please visit either the \m[blue]MySQL Forums\m[] or \m[blue]MySQL Mailing Lists\m[] where you can discuss your issues with other MySQL users.

For additional documentation on MySQL products, including translations of the documentation into other languages, and downloadable versions in variety of formats, including HTML and PDF formats, see the \m[blue]MySQL Documentation Library\m[].

SEE ALSO

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

Oracle Corporation (http://dev.mysql.com/).


MySQL 5.5 \FBMYSQLCHECK\FR (1) 03/22/2013
blog comments powered by Disqus