'\" t
.\"     Title: \fBmysqlindexcheck\fR
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: 08/30/2013
.\"    Manual: MySQL Utilities
.\"    Source: MySQL 1.3.4
.\"  Language: English
.\"
.TH "\FBMYSQLINDEXCHECK\F" "1" "08/30/2013" "MySQL 1\&.3\&.4" "MySQL Utilities"
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.\" mysqlindexcheck
.\" utilities: mysqlindexcheck
.\" scripts
.SH "NAME"
mysqlindexcheck \- Identify Potentially Redundant Table Indexes
.SH "SYNOPSIS"
.HP \w'\fBmysqlindexcheck\ [\fR\fB\fIoptions\fR\fR\fB]\ \fR\fB\fIdb\fR\fR\fB[\fR\fB\fI:table\fR\fR\fB]\ \&.\&.\&.\fR\ 'u
\fBmysqlindexcheck [\fR\fB\fIoptions\fR\fR\fB] \fR\fB\fIdb\fR\fR\fB[\fR\fB\fI:table\fR\fR\fB] \&.\&.\&.\fR
.SH "DESCRIPTION"
.PP
This utility reads the indexes for one or more tables and identifies duplicate and potentially redundant indexes\&.
.PP
To check all tables in a database, specify only the database name\&. To check a specific table, name the table in
\fIdb\&.table\fR
format\&. It is possible to mix database and table names\&.
.PP
You can scan tables in any database except the internal databases
\fBmysql\fR,
\fBINFORMATION_SCHEMA\fR, and
\fBperformance_schema\fR\&.
.PP
Depending on the index type, the utility applies the following rules to compare indexes (designated as
idx_a
and
idx_b):
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBBTREE\fR
.sp
idx_b
is redundant to
idx_a
if and only if the first
\fIn\fR
columns in
idx_b
also appear in
idx_a\&. Order and uniqueness count\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBHASH\fR
.sp
idx_a
and
idx_b
are duplicates if and only if they contain the same columns in the same order\&. Uniqueness counts\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBSPATIAL\fR
.sp
idx_a
and
idx_b
are duplicates if and only if they contain the same column (only one column is permitted)\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBFULLTEXT\fR
.sp
idx_b
is redundant to
idx_a
if and only if all columns in
idx_b
are included in
idx_a\&. Order counts\&.
.RE
.PP
To see
\fBDROP\fR
statements to drop redundant indexes, specify the
\fB\-\-show\-drops\fR
option\&. To examine the existing indexes, use the
\fB\-\-verbose\fR
option, which prints the equivalent
\fBCREATE INDEX\fR
(or
\fBALTER TABLE\fR
for primary keys\&.
.PP
To display the best or worst nonprimary key indexes for each table, use the
\fB\-\-best\fR
or
\fB\-\-worst\fR
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\&.
.PP
To change the format of the index lists displayed for the
\fB\-\-show\-indexes\fR,
\fB\-\-best\fR, and
\fB\-\-worst\fR
options, use one of the following values with the
\fB\-\-format\fR
option:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBgrid\fR
(default)
.sp
Display output in grid or table format like that of the
\fBmysql\fR
monitor\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBcsv\fR
.sp
Display output in comma\-separated values format\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBtab\fR
.sp
Display output in tab\-separated format\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBsql\fR
.sp
print SQL statements rather than a list\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fBvertical\fR
.sp
Display output in single\-column format like that of the
\eG
command for the
\fBmysql\fR
monitor\&.
.RE
.PP
Note: The
\fB\-\-best\fR
and
\fB\-\-worst\fR
lists cannot be printed as SQL statements\&.
      OPTIONS
.PP
\fBmysqlindexcheck\fR
accepts the following command\-line options:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-help
.sp
Display a help message and exit\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-best[=<N>]
.sp
If
\fB\-\-stats\fR
is given, limit index statistics to the best
\fIN\fR
indexes\&. The default value of
\fIN\fR
is 5 if omitted\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-format=<index_format>, \-f<index_format>
.sp
Specify the index list display format for output produced by
\fB\-\-stats\fR\&. Permitted format values are
\fBgrid\fR,
\fBcsv\fR,
\fBtab\fR,
\fBsql\fR, and
\fBvertical\fR\&. The default is
\fBgrid\fR\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-server=<source>
.sp
Connection information for the server in the format: <\fIuser\fR>[:<\fIpasswd\fR>]@<\fIhost\fR>[:<\fIport\fR>][:<\fIsocket\fR>] or <\fIlogin\-path\fR>[:<\fIport\fR>][:<\fIsocket\fR>]\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-show\-drops, \-d
.sp
Display
\fBDROP\fR
statements for dropping indexes\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-show\-indexes, \-i
.sp
Display indexes for each table\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-skip, \-s
.sp
Skip tables that do not exist\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-stats
.sp
Show index performance statistics\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-verbose, \-v
.sp
Specify how much information to display\&. Use this option multiple times to increase the amount of information\&. For example,
\fB\-v\fR
= verbose,
\fB\-vv\fR
= more verbose,
\fB\-vvv\fR
= debug\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-version
.sp
Display version information and exit\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-\-worst[=<N>]
.sp
If
\fB\-\-stats\fR
is given, limit index statistics to the worst
\fIN\fR
indexes\&. The default value of
\fIN\fR
is 5 if omitted\&.
.RE
      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\&.
.PP
For the
\fB\-\-format\fR
option, the permitted values are not case sensitive\&. In addition, values may be specified as any unambiguous prefix of a valid value\&. For example,
\fB\-\-format=g\fR
specifies the grid format\&. An error occurs if a prefix matches more than one valid value\&.
.PP
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:
.sp
.if n \{\
.RS 4
.\}
.nf
$ mysqlindexcheck \-\-server=root@localhost employees
# Source on localhost: \&.\&.\&. connected\&.
# The following indexes are duplicates or redundant \e
  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 \e
  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 \e
  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 \e
  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)
.fi
.if n \{\
.RE
.\}
.SH "COPYRIGHT"
.br
.SH "SEE ALSO"
For more information, please refer to the MySQL Utilities section
of the MySQL Workbench Reference Manual, which is available online
at http://dev.mysql.com/doc/workbench/en/.
.SH AUTHOR
Oracle Corporation (http://dev.mysql.com/).