MYSQLINDEXCHECK                 MySQL Utilities                MYSQLINDEXCHECK



NAME
       mysqlindexcheck - Identify Potentially Redundant Table Indexes

SYNOPSIS
       mysqlindexcheck [options] db[:table] ...

DESCRIPTION
       This utility reads the indexes for one or more tables and identifies
       duplicate and potentially redundant indexes.

       To check all tables in a database, only specify the database name. To
       check a specific table, name the table in db.table format. It is
       possible to mix database and table names.

       You can scan tables in any database except the internal databases
       mysql, INFORMATION_SCHEMA, and performance_schema.

       Depending on the index type, the utility applies the following rules to
       compare indexes (designated as idx_a and idx_b):

       o   BTREE

           idx_b is redundant to idx_a if and only if all the columns from
           idx_b are a prefix of idx_a. Order and uniqueness count.

       o   HASH

           idx_a and idx_b are redundant if they are duplicates, i.e. if and
           only if they contain the same columns in the same order.

       o   SPATIAL

           idx_a and idx_b are duplicates if and only if they contain the same
           column (only one column is permitted).

       o   FULLTEXT

           idx_b is redundant to idx_a if and only if all columns in idx_b are
           included in idx_a. Order does not count.

       To see DROP statements drop redundant indexes, specify the --show-drops
       option. To examine the existing indexes, use the --verbose option,
       which prints the equivalent CREATE INDEX (or ALTER TABLE) for primary
       keys.

       To display the best or worst non-primary key indexes for each table,
       use the --best or --worst option. This causes the output to show the
       best or worst indexes from tables with 10 or more rows. By default,
       each option shows five indexes. To override that, provide an integer
       value for the option.

       To change the format of the index lists displayed for the
       --show-indexes, --best, and --worst options, use one of the following
       values with the --format option:

       o   grid (default)

           Display output in grid or table format like that of the mysql
           client command-line tool.

       o   csv

           Display output in comma-separated values format.

       o   tab

           Display output in tab-separated format.

       o   sql

           Print SQL statements rather than a list.

       o   vertical

           Display output in single-column format like that of the \G command
           for the mysql client command-line tool.

           Note
           The --best and --worst lists cannot be printed as SQL statements.
       OPTIONS.PP mysqlindexcheck accepts the following command-line options:

       o   --help

           Display a help message and exit.

       o   --license

           Display license information and exit.

       o   --best[=<N>]

           If --stats is given, limit index statistics to the best N indexes.
           The default value of N is 5 if omitted.

       o   --format=<index_format>, -f<index_format>

           Specify the index list display format for output produced by
           --stats. Permitted format values are grid, csv, tab, sql, and
           vertical. The default is grid.

       o   --report-indexes, -r

           Reports if a table has neither UNIQUE indexes nor a PRIMARY key.

       o   --server=<source>

           Connection information for the server.

           To connect to a server, it is necessary to specify connection
           parameters such as user name, host name, password, and either a
           port or socket. MySQL Utilities provides a number of ways to
           provide this information. All of the methods require specifying
           your choice via a command-line option such as --server, --master,
           --slave, etc. The methods include the following in order of most
           secure to least secure.

           o   Use login-paths from your .mylogin.cnf file (encrypted, not
               visible). Example : <login-path>[:<port>][:<socket>]

           o   Use a configuration file (unencrypted, not visible) Note:
               available in release-1.5.0. Example :
               <configuration-file-path>[:<section>]

           o   Specify the data on the command-line (unencrypted, visible).
               Example : <user>[:<passwd>]@<host>[:<port>][:<socket>]


       o   --show-drops, -d

           Display DROP statements for dropping indexes.

       o   --show-indexes, -i

           Display indexes for each table.

       o   --skip, -s

           Skip tables that do not exist.

       o   --ssl-ca

           The path to a file that contains a list of trusted SSL CAs.

       o   --ssl-cert

           The name of the SSL certificate file to use for establishing a
           secure connection.

       o   --ssl-cert

           The name of the SSL key file to use for establishing a secure
           connection.

       o   --ssl

           Specifies if the server connection requires use of SSL. If an
           encrypted connection cannot be established, the connection attempt
           fails. Default setting is 0 (SSL not required).

       o   --stats

           Show index performance statistics.

       o   --verbose, -v

           Specify how much information to display. Use this option multiple
           times to increase the amount of information. For example, -v =
           verbose, -vv = more verbose, -vvv = debug.

       o   --version

           Display version information and exit.

       o   --worst[=<N>]

           If --stats is also passed in, limit index statistics to the worst N
           indexes. The default value of N is 5, if omitted.
       NOTES.PP You must provide connection parameters (user, host, password,
       and so forth) for an account that has the appropriate privileges to
       read all objects accessed during the operation.

       For the --format option, the permitted values are not case sensitive.
       In addition, values may be specified as any unambiguous prefix of a
       valid value. For example, --format=g specifies the grid format. An
       error occurs if a prefix matches more than one valid value.

       The path to the MySQL client tools should be included in the PATH
       environment variable in order to use the authentication mechanism with
       login-paths. This will allow the utility to use the my_print_defaults
       tools which is required to read the login-path values from the login
       configuration file (.mylogin.cnf).  EXAMPLES.PP To check all tables in
       the employees database on the local server to see the possible
       redundant and duplicate indexes, use this command:

           shell> mysqlindexcheck --server=root@localhost employees
           # Source on localhost: ... connected.
           # The following indexes are duplicates or redundant \
             for table employees.dept_emp:
           #
           CREATE INDEX emp_no ON employees.dept_emp (emp_no) USING BTREE
           #     may be redundant or duplicate of:
           ALTER TABLE employees.dept_emp ADD PRIMARY KEY (emp_no, dept_no)
           # The following indexes are duplicates or redundant \
             for table employees.dept_manager:
           #
           CREATE INDEX emp_no ON employees.dept_manager (emp_no) USING BTREE
           #     may be redundant or duplicate of:
           ALTER TABLE employees.dept_manager ADD PRIMARY KEY (emp_no, dept_no)
           # The following indexes are duplicates or redundant \
             for table employees.salaries:
           #
           CREATE INDEX emp_no ON employees.salaries (emp_no) USING BTREE
           #     may be redundant or duplicate of:
           ALTER TABLE employees.salaries ADD PRIMARY KEY (emp_no, from_date)
           # The following indexes are duplicates or redundant \
             for table employees.titles:
           #
           CREATE INDEX emp_no ON employees.titles (emp_no) USING BTREE
           #     may be redundant or duplicate of:
           ALTER TABLE employees.titles ADD PRIMARY KEY (emp_no, title, from_date)

       PERMISSIONS REQUIRED.PP Regarding the privileges needed to run this
       utility, the user needs SELECT privilege on the mysql database as well
       as for the databases which tables are being checked.

COPYRIGHT
       Copyright (C) 2006, 2015, Oracle and/or its affiliates. All rights
       reserved.

       This documentation is free software; you can redistribute it and/or
       modify it only under the terms of the GNU General Public License as
       published by the Free Software Foundation; version 2 of the License.

       This documentation is distributed in the hope that it will be useful,
       but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
       General Public License for more details.

       You should have received a copy of the GNU General Public License along
       with the program; if not, write to the Free Software Foundation, Inc.,
       51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see
       http://www.gnu.org/licenses/.


SEE ALSO
       For more information, please refer to the MySQL Utilities and Fabric
       documentation, which is available online at
       http://dev.mysql.com/doc/index-utils-fabric.html

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



MySQL 1.5.6                       09/15/2015                   MYSQLINDEXCHECK
