PT-CONFIG-DIFF(1p)					User Contributed Perl Documentation					PT-CONFIG-DIFF(1p)

NAME

       pt-config-diff - Diff MySQL configuration files and server variables.

SYNOPSIS

       Usage: pt-config-diff [OPTION...] CONFIG CONFIG [CONFIG...]

       pt-config-diff diffs MySQL configuration files and server variables.  CONFIG can be a filename or a DSN.  At least two CONFIG sources must
       be given.  Like standard Unix diff, there is no output if there are no differences.

       Diff host1 config from SHOW VARIABLES against host2:

	 pt-config-diff h=host1 h=host2

       Diff config from [mysqld] section in my.cnf against host1 config:

	 pt-config-diff /etc/my.cnf h=host1

       Diff the [mysqld] section of two option files:

	  pt-config-diff /etc/my-small.cnf /etc/my-large.cnf

RISKS

       The following section is included to inform users about the potential risks, whether known or unknown, of using this tool.  The two main
       categories of risks are those created by the nature of the tool (e.g. read-only tools vs. read-write tools) and those created by bugs.

       pt-config-diff reads MySQL's configuration and examines it and is thus very low risk.

       At the time of this release there are no known bugs that pose a serious risk.

       The authoritative source for updated information is always the online issue tracking system.  Issues that affect this tool will be marked
       as such.  You can see a list of such issues at the following URL: http://www.percona.com/bugs/pt-config-diff
       <http://www.percona.com/bugs/pt-config-diff>.

       See also "BUGS" for more information on filing bugs and getting help.

DESCRIPTION

       pt-config-diff diffs MySQL configurations by examining the values of server system variables from two or more CONFIG sources specified on
       the command line.  A CONFIG source can be a DSN or a filename containing the output of "mysqld --help --verbose", "my_print_defaults",
       "SHOW VARIABLES", or an option file (e.g. my.cnf).

       For each DSN CONFIG, pt-config-diff connects to MySQL and gets variables and values by executing "SHOW /*!40103 GLOBAL*/ VARIABLES".  This
       is an "active config" because it shows what server values MySQL is actively (currently) running with.

       Only variables that all CONFIG sources have are compared because if a variable is not present then we cannot know or safely guess its
       value.  For example, if you compare an option file (e.g. my.cnf) to an active config (i.e. SHOW VARIABLES from a DSN CONFIG), the option
       file will probably only have a few variables, whereas the active config has every variable.  Only values of the variables present in both
       configs are compared.

       Option file and DSN configs provide the best results.

OUTPUT

       There is no output when there are no differences.  When there are differences, pt-config-diff prints a report to STDOUT that looks similar
       to the following:

	 2 config differences
	 Variable		   my.master.cnf   my.slave.cnf
	 ========================= =============== ===============
	 datadir		   /tmp/12345/data /tmp/12346/data
	 port			   12345	   12346

       Comparing MySQL variables is difficult because there are many variations and subtleties across the many versions and distributions of
       MySQL.  When a comparison fails, the tool prints a warning to STDERR, such as the following:

	 Comparing log_error values (mysqld.log, /tmp/12345/data/mysqld.log)
	 caused an error: Argument "/tmp/12345/data/mysqld.log" isn't numeric
	 in numeric eq (==) at ./pt-config-diff line 2311.

       Please report these warnings so the comparison functions can be improved.

EXIT STATUS

       pt-config-diff exits with a zero exit status when there are no differences, and 1 if there are.

OPTIONS

       This tool accepts additional command-line arguments.  Refer to the "SYNOPSIS" and usage information for details.

       --ask-pass
	   Prompt for a password when connecting to MySQL.

       --charset
	   short form: -A; type: string

	   Default character set.  If the value is utf8, sets Perl's binmode on STDOUT to utf8, passes the mysql_enable_utf8 option to DBD::mysql,
	   and runs SET NAMES UTF8 after connecting to MySQL.  Any other value sets binmode on STDOUT without the utf8 layer, and runs SET NAMES
	   after connecting to MySQL.

       --config
	   type: Array

	   Read this comma-separated list of config files; if specified, this must be the first option on the command line.  (This option does not
	   specify a CONFIG; it's equivalent to "--defaults-file".)

       --daemonize
	   Fork to the background and detach from the shell.  POSIX operating systems only.

       --defaults-file
	   short form: -F; type: string

	   Only read mysql options from the given file.  You must give an absolute pathname.

       --help
	   Show help and exit.

       --host
	   short form: -h; type: string

	   Connect to host.

       --ignore-variables
	   type: array

	   Ignore, do not compare, these variables.

       --password
	   short form: -p; type: string

	   Password to use for connection.

       --pid
	   type: string

	   Create the given PID file when daemonized.  The file contains the process ID of the daemonized instance.  The PID file is removed when
	   the daemonized instance exits.  The program checks for the existence of the PID file when starting; if it exists and the process with
	   the matching PID exists, the program exits.

       --port
	   short form: -P; type: int

	   Port number to use for connection.

       --[no]report
	   default: yes

	   Print the MySQL config diff report to STDOUT.  If you just want to check if the given configs are different or not by examining the
	   tool's exit status, then specify "--no-report" to suppress the report.

       --report-width
	   type: int; default: 78

	   Truncate report lines to this many characters.  Since some variable values can be long, or when comparing multiple configs, it may help
	   to increase the report width so values are not truncated beyond readability.

       --set-vars
	   type: string; default: wait_timeout=10000

	   Set these MySQL variables.  Immediately after connecting to MySQL, this string will be appended to SET and executed.

       --socket
	   short form: -S; type: string

	   Socket file to use for connection.

       --user
	   short form: -u; type: string

	   MySQL user if not current user.

       --version
	   Show version and exit.

DSN OPTIONS

       These DSN options are used to create a DSN.  Each option is given like "option=value".  The options are case-sensitive, so P and p are not
       the same option.  There cannot be whitespace before or after the "=" and if the value contains whitespace it must be quoted.  DSN options
       are comma-separated.  See the percona-toolkit manpage for full details.

       o   A

	   dsn: charset; copy: yes

	   Default character set.

       o   D

	   dsn: database; copy: yes

	   Default database.

       o   F

	   dsn: mysql_read_default_file; copy: yes

	   Only read default options from the given file

       o   h

	   dsn: host; copy: yes

	   Connect to host.

       o   p

	   dsn: password; copy: yes

	   Password to use when connecting.

       o   P

	   dsn: port; copy: yes

	   Port number to use for connection.

       o   S

	   dsn: mysql_socket; copy: yes

	   Socket file to use for connection.

       o   u

	   dsn: user; copy: yes

	   User for login if not current user.

ENVIRONMENT

       The environment variable "PTDEBUG" enables verbose debugging output to STDERR.  To enable debugging and capture all output to a file, run
       the tool like:

	  PTDEBUG=1 pt-config-diff ... > FILE 2>&1

       Be careful: debugging output is voluminous and can generate several megabytes of output.

SYSTEM REQUIREMENTS

       You need Perl, DBI, DBD::mysql, and some core packages that ought to be installed in any reasonably new version of Perl.

BUGS

       For a list of known bugs, see http://www.percona.com/bugs/pt-config-diff <http://www.percona.com/bugs/pt-config-diff>.

       Please report bugs at https://bugs.launchpad.net/percona-toolkit <https://bugs.launchpad.net/percona-toolkit>.  Include the following
       information in your bug report:

       o   Complete command-line used to run the tool

       o   Tool "--version"

       o   MySQL version of all servers involved

       o   Output from the tool including STDERR

       o   Input files (log/dump/config files, etc.)

       If possible, include debugging output by running the tool with "PTDEBUG"; see "ENVIRONMENT".

DOWNLOADING

       Visit http://www.percona.com/software/percona-toolkit/ <http://www.percona.com/software/percona-toolkit/> to download the latest release of
       Percona Toolkit.  Or, get the latest release from the command line:

	  wget percona.com/get/percona-toolkit.tar.gz

	  wget percona.com/get/percona-toolkit.rpm

	  wget percona.com/get/percona-toolkit.deb

       You can also get individual tools from the latest release:

	  wget percona.com/get/TOOL

       Replace "TOOL" with the name of any tool.

AUTHORS

       Baron Schwartz and Daniel Nichter

ABOUT PERCONA TOOLKIT

       This tool is part of Percona Toolkit, a collection of advanced command-line tools developed by Percona for MySQL support and consulting.
       Percona Toolkit was forked from two projects in June, 2011: Maatkit and Aspersa.  Those projects were created by Baron Schwartz and
       developed primarily by him and Daniel Nichter, both of whom are employed by Percona.  Visit <http://www.percona.com/software/> for more
       software developed by Percona.

COPYRIGHT, LICENSE, AND WARRANTY
       This program is copyright 2011-2012 Percona Inc.  Feedback and improvements are welcome.

       THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
       MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

       This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
       the Free Software Foundation, version 2; OR the Perl Artistic License.  On UNIX and similar systems, you can issue `man perlgpl' or `man
       perlartistic' to read these licenses.

       You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation,
       Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.

VERSION

       pt-config-diff 2.1.2

perl v5.14.2							    2012-06-15							PT-CONFIG-DIFF(1p)