.. program:: pt-config-diff =========================== :program:`pt-config-diff` =========================== .. highlight:: perl NAME ==== :program:`pt-config-diff` - Diff MySQL configuration files and server variables. SYNOPSIS ======== Usage ----- :: pt-config-diff [OPTION...] CONFIG CONFIG [CONFIG...] :program:`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``: .. code-block:: perl pt-config-diff h=host1 h=host2 Diff config from ``[mysqld]`` section in :file:`my.cnf` against ``host1`` config: .. code-block:: perl pt-config-diff /etc/my.cnf h=host1 Diff the ``[mysqld]`` section of two option files: .. code-block:: perl 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 `_. See also "BUGS" for more information on filing bugs and getting help. DESCRIPTION =========== :program:`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``, :program:`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. :file:`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, :program:`pt-config-diff` prints a report to ``STDOUT`` that looks similar to the following: .. code-block:: perl 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: .. code-block:: perl 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 =========== :program:`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. .. option:: --ask-pass Prompt for a password when connecting to MySQL. .. option:: --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. .. option:: --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``\ .) .. option:: --daemonize Fork to the background and detach from the shell. POSIX operating systems only. .. option:: --defaults-file short form: -F; type: string Only read mysql options from the given file. You must give an absolute pathname. .. option:: --help Show help and exit. .. option:: --host short form: -h; type: string Connect to host. .. option:: --ignore-variables type: array Ignore, do not compare, these variables. .. option:: --password short form: -p; type: string Password to use for connection. .. option:: --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. .. option:: --port short form: -P; type: int Port number to use for connection. .. option:: --[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. .. option:: --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. .. option:: --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. .. option:: --socket short form: -S; type: string Socket file to use for connection. .. option:: --user short form: -u; type: string MySQL user if not current user. .. option:: --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. * 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. * 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. 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: .. code-block:: perl 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 `_. If possible, include debugging output by running the tool with \ ``PTDEBUG``\ ; see "ENVIRONMENT". AUTHORS ======= Baron Schwartz and Daniel Nichter COPYRIGHT, LICENSE, AND WARRANTY ================================ This program is copyright 2011 Percona Inc. Feedback and improvements are welcome. VERSION ======= pt-config-diff 1.0.1