Provided by: percona-toolkit_3.0.13-1_all bug


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


       Usage: pt-config-diff [OPTIONS] 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


       Percona Toolkit is mature, proven in the real world, and well tested, but all database
       tools can pose a risk to the system and the database server.  Before using this tool,

       ·   Read the tool's documentation

       ·   Review the tool's known "BUGS"

       ·   Test the tool on a non-production server

       ·   Backup your production server and verify the backups


       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.


       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.


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


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

           Prompt for a password when connecting to MySQL.

           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.

           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".)

           short form: -D; type: string

           Connect to this database.

           short form: -F; type: string

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

           Show help and exit.

           short form: -h; type: string

           Connect to host.

           default: yes

           Compare the variables case-insensitively.

           type: array

           Ignore, do not compare, these variables.

           short form: -p; type: string

           Password to use for connection.

           type: string

           Create the given PID file.  The tool won't start if the PID file already exists and
           the PID it contains is different than the current PID.  However, if the PID file
           exists and the PID it contains is no longer running, the tool will overwrite the PID
           file with the current PID.  The PID file is removed automatically when the tool exits.

           short form: -P; type: int

           Port number to use for connection.

           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.

           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.

           type: Array

           Set the MySQL variables in this comma-separated list of "variable=value" pairs.

           By default, the tool sets:


           Variables specified on the command line override these defaults.  For example,
           specifying "--set-vars wait_timeout=500" overrides the defaultvalue of 10000.

           The tool prints a warning and continues if a variable cannot be set.

           short form: -S; type: string

           Socket file to use for connection.

           short form: -u; type: string

           MySQL user if not current user.

           Show version and exit.

           default: yes

           Check for the latest version of Percona Toolkit, MySQL, and other programs.

           This is a standard "check for updates automatically" feature, with two additional
           features.  First, the tool checks its own version and also the versions of the
           following software: operating system, Percona Monitoring and Management (PMM), MySQL,
           Perl, MySQL driver for Perl (DBD::mysql), and Percona Toolkit. Second, it checks for
           and warns about versions with known problems. For example, MySQL 5.5.25 had a critical
           bug and was re-released as 5.5.25a.

           A secure connection to Percona’s Version Check database server is done to perform
           these checks. Each request is logged by the server, including software version numbers
           and unique ID of the checked system. The ID is generated by the Percona Toolkit
           installation script or when the Version Check database call is done for the first

           Any updates or known problems are printed to STDOUT before the tool's normal output.
           This feature should never interfere with the normal operation of the tool.

           For more information, visit


       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.

       ·   A

           dsn: charset; copy: yes

           Default character set.

       ·   D

           dsn: database; copy: yes

           Default database.

       ·   F

           dsn: mysql_read_default_file; copy: yes

           Only read default options from the given file

       ·   h

           dsn: host; copy: yes

           Connect to host.

       ·   p

           dsn: password; copy: yes

           Password to use when connecting.  If password contains commas they must be escaped
           with a backslash: "exam\,ple"

       ·   P

           dsn: port; copy: yes

           Port number to use for connection.

       ·   S

           dsn: mysql_socket; copy: yes

           Socket file to use for connection.

       ·   u

           dsn: user; copy: yes

           User for login if not current user.


       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.


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


       For a list of known bugs, see <>.

       Please report bugs at <>.  Include the following
       information in your bug report:

       ·   Complete command-line used to run the tool

       ·   Tool "--version"

       ·   MySQL version of all servers involved

       ·   Output from the tool including STDERR

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

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


       Visit <> to download the latest release of
       Percona Toolkit.  Or, get the latest release from the command line:




       You can also get individual tools from the latest release:


       Replace "TOOL" with the name of any tool.


       Baron Schwartz and Daniel Nichter


       This tool is part of Percona Toolkit, a collection of advanced command-line tools for
       MySQL developed by Percona.  Percona Toolkit was forked from two projects in June, 2011:
       Maatkit and Aspersa.  Those projects were created by Baron Schwartz and primarily
       developed by him and Daniel Nichter.  Visit <> to learn
       about other free, open-source software from Percona.


       This program is copyright 2011-2018 Percona LLC and/or its affiliates.


       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.


       pt-config-diff 3.0.13


       Hey! The above document had some coding errors, which are explained below:

       Around line 5728:
           Non-ASCII character seen before =encoding in 'Percona’s'. Assuming UTF-8