|o||Read the tools documentation|
|o||Review the tools known BUGS|
|o||Test the tool on a non-production server|
|o||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" isnt 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 are.
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 Perls 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; its equivalent to --defaults-file.)
--database short form: -D; type: string
Connect to this database.
--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.
--[no]ignore-case default: yes
Compare the variables case-insensitively.
--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. The tool wont 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.
--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 tools 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: 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.
--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. --[no]version-check default: yes
This is a standard check for updates automatically feature, with two additional features. First, the tool checks the version of other programs on the local system in addition to its own version. For example, it checks the version of every MySQL server it connects to, Perl, and the Perl module DBD::mysql. 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.
Any updates or known problems are printed to STDOUT before the tools normal output. This feature should never interfere with the normal operation of the tool.
For more information, visit <https://www.percona.com/version-check>.
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.
dsn: charset; copy: yes
Default character set.
dsn: database; copy: yes
dsn: mysql_read_default_file; copy: yes
Only read default options from the given file
dsn: host; copy: yes
Connect to host.
dsn: password; copy: yes
Password to use when connecting.
dsn: port; copy: yes
Port number to use for connection.
dsn: mysql_socket; copy: yes
Socket file to use for connection.
dsn: user; copy: yes
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 <http://www.percona.com/bugs/pt-config-diff>.
Please report bugs at <https://bugs.launchpad.net/percona-toolkit>. Include the following information in your bug report:
If possible, include debugging output by running the tool with PTDEBUG; see ENVIRONMENT.
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.)
Visit <http://www.percona.com/software/percona-toolkit/> to download the latest release of Percona Toolkit. Or, get the latest release from the command line:
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 <http://www.percona.com/software/> to learn about other free, open-source software from Percona.
This program is copyright 2011-2015 Percona LLC and/or its affiliates.
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.
|perl v5.20.3||PT-CONFIG-DIFF (1)||2015-04-10|