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- Committer: Daniel Nichter
- Date: 2011-12-29 22:16:13 UTC
- Revision ID: daniel@percona.com-20111229221613-oprw0q2td34r6zkb
Update release date.
- files removed:
- docs/user/authors.rst
- files modified:
- Changelog
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docs/user/pt-slave-restart.rst
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################
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pt-slave-restart
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################
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.. highlight:: perl
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****
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NAME
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****
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pt-slave-restart - Watch and restart MySQL replication after errors.
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********
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SYNOPSIS
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********
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Usage: pt-slave-restart [OPTION...] [DSN]
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pt-slave-restart watches one or more MySQL replication slaves for
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errors, and tries to restart replication if it stops.
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*****
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RISKS
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*****
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The following section is included to inform users about the potential risks,
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whether known or unknown, of using this tool. The two main categories of risks
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are those created by the nature of the tool (e.g. read-only tools vs. read-write
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tools) and those created by bugs.
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pt-slave-restart is a brute-force way to try to keep a slave server running when
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it is having problems with replication. Don't be too hasty to use it unless you
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need to. If you use this tool carelessly, you might miss the chance to really
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solve the slave server's problems.
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At the time of this release there is a bug that causes an invalid
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\ ``CHANGE MASTER TO``\ statement to be executed.
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The authoritative source for updated information is always the online issue
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tracking system. Issues that affect this tool will be marked as such. You can
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see a list of such issues at the following URL:
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`http://www.percona.com/bugs/pt-slave-restart <http://www.percona.com/bugs/pt-slave-restart>`_.
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See also "BUGS" for more information on filing bugs and getting help.
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***********
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DESCRIPTION
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***********
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pt-slave-restart watches one or more MySQL replication slaves and tries to skip
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statements that cause errors. It polls slaves intelligently with an
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exponentially varying sleep time. You can specify errors to skip and run the
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slaves until a certain binlog position.
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Note: it has come to my attention that Yahoo! had or has an internal tool
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called fix_repl, described to me by a past Yahoo! employee and mentioned in
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the first edition of High Performance MySQL. Apparently this tool does the
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same thing. Make no mistake, though: this is not a way to "fix replication."
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In fact I would not even encourage its use on a regular basis; I use it only
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when I have an error I know I just need to skip past.
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******
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OUTPUT
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******
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If you specify "--verbose", pt-slave-restart prints a line every time it sees
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the slave has an error. See "--verbose" for details.
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*****
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SLEEP
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*****
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pt-slave-restart sleeps intelligently between polling the slave. The current
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sleep time varies.
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\*
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The initial sleep time is given by "--sleep".
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\*
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If it checks and finds an error, it halves the previous sleep time.
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\*
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If it finds no error, it doubles the previous sleep time.
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\*
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The sleep time is bounded below by "--min-sleep" and above by
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"--max-sleep".
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\*
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Immediately after finding an error, pt-slave-restart assumes another error is
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very likely to happen next, so it sleeps the current sleep time or the initial
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sleep time, whichever is less.
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***********
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EXIT STATUS
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***********
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An exit status of 0 (sometimes also called a return value or return code)
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indicates success. Any other value represents the exit status of the Perl
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process itself, or of the last forked process that exited if there were multiple
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servers to monitor.
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*************
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COMPATIBILITY
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*************
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pt-slave-restart should work on many versions of MySQL. Lettercase of many
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output columns from SHOW SLAVE STATUS has changed over time, so it treats them
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all as lowercase.
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*******
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OPTIONS
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*******
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This tool accepts additional command-line arguments. Refer to the
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"SYNOPSIS" and usage information for details.
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--always
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Start slaves even when there is no error. With this option enabled,
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pt-slave-restart will not let you stop the slave manually if you want to!
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--ask-pass
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Prompt for a password when connecting to MySQL.
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--charset
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short form: -A; type: string
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Default character set. If the value is utf8, sets Perl's binmode on
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STDOUT to utf8, passes the mysql_enable_utf8 option to DBD::mysql, and
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runs SET NAMES UTF8 after connecting to MySQL. Any other value sets
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binmode on STDOUT without the utf8 layer, and runs SET NAMES after
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connecting to MySQL.
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--[no]check-relay-log
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default: yes
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Check the last relay log file and position before checking for slave errors.
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By default pt-slave-restart will not doing anything (it will just sleep)
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if neither the relay log file nor the relay log position have changed since
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the last check. This prevents infinite loops (i.e. restarting the same
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error in the same relay log file at the same relay log position).
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For certain slave errors, however, this check needs to be disabled by
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specifying \ ``--no-check-relay-log``\ . Do not do this unless you know what
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you are doing!
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--config
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type: Array
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Read this comma-separated list of config files; if specified, this must be the
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first option on the command line.
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--daemonize
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Fork to the background and detach from the shell. POSIX
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operating systems only.
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--database
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short form: -D; type: string
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Database to use.
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--defaults-file
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short form: -F; type: string
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Only read mysql options from the given file. You must give an absolute
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pathname.
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--error-length
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type: int
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Max length of error message to print. When "--verbose" is set high enough to
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print the error, this option will truncate the error text to the specified
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length. This can be useful to prevent wrapping on the terminal.
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--error-numbers
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type: hash
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Only restart this comma-separated list of errors. Makes pt-slave-restart only
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try to restart if the error number is in this comma-separated list of errors.
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If it sees an error not in the list, it will exit.
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The error number is in the \ ``last_errno``\ column of \ ``SHOW SLAVE STATUS``\ .
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--error-text
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type: string
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Only restart errors that match this pattern. A Perl regular expression against
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which the error text, if any, is matched. If the error text exists and matches,
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pt-slave-restart will try to restart the slave. If it exists but doesn't match,
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pt-slave-restart will exit.
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The error text is in the \ ``last_error``\ column of \ ``SHOW SLAVE STATUS``\ .
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--help
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Show help and exit.
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--host
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short form: -h; type: string
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Connect to host.
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--log
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type: string
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Print all output to this file when daemonized.
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--max-sleep
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type: float; default: 64
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Maximum sleep seconds.
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The maximum time pt-slave-restart will sleep before polling the slave again.
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This is also the time that pt-slave-restart will wait for all other running
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instances to quit if both "--stop" and "--monitor" are specified.
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See "SLEEP".
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--min-sleep
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type: float; default: 0.015625
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The minimum time pt-slave-restart will sleep before polling the slave again.
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See "SLEEP".
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--monitor
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Whether to monitor the slave (default). Unless you specify --monitor
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explicitly, "--stop" will disable it.
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--password
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short form: -p; type: string
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Password to use when connecting.
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--pid
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type: string
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Create the given PID file when daemonized. The file contains the process
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ID of the daemonized instance. The PID file is removed when the
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daemonized instance exits. The program checks for the existence of the
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PID file when starting; if it exists and the process with the matching PID
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exists, the program exits.
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--port
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short form: -P; type: int
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Port number to use for connection.
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--quiet
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short form: -q
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Suppresses normal output (disables "--verbose").
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--recurse
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type: int; default: 0
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Watch slaves of the specified server, up to the specified number of servers deep
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in the hierarchy. The default depth of 0 means "just watch the slave
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specified."
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pt-slave-restart examines \ ``SHOW PROCESSLIST``\ and tries to determine which
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connections are from slaves, then connect to them. See "--recursion-method".
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Recursion works by finding all slaves when the program starts, then watching
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them. If there is more than one slave, \ ``pt-slave-restart``\ uses \ ``fork()``\ to
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monitor them.
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This also works if you have configured your slaves to show up in \ ``SHOW SLAVE
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HOSTS``\ . The minimal configuration for this is the \ ``report_host``\ parameter, but
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there are other "report" parameters as well for the port, username, and
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password.
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--recursion-method
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type: string
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Preferred recursion method used to find slaves.
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Possible methods are:
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.. code-block:: perl
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METHOD USES
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=========== ================
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processlist SHOW PROCESSLIST
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hosts SHOW SLAVE HOSTS
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The processlist method is preferred because SHOW SLAVE HOSTS is not reliable.
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However, the hosts method is required if the server uses a non-standard
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port (not 3306). Usually pt-slave-restart does the right thing and finds
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the slaves, but you may give a preferred method and it will be used first.
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If it doesn't find any slaves, the other methods will be tried.
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--run-time
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type: time
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Time to run before exiting. Causes pt-slave-restart to stop after the specified
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time has elapsed. Optional suffix: s=seconds, m=minutes, h=hours, d=days; if no
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suffix, s is used.
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--sentinel
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type: string; default: /tmp/pt-slave-restart-sentinel
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Exit if this file exists.
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--set-vars
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type: string; default: wait_timeout=10000
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Set these MySQL variables. Immediately after connecting to MySQL, this string
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will be appended to SET and executed.
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--skip-count
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type: int; default: 1
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Number of statements to skip when restarting the slave.
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--sleep
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type: int; default: 1
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Initial sleep seconds between checking the slave.
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See "SLEEP".
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--socket
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short form: -S; type: string
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Socket file to use for connection.
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--stop
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Stop running instances by creating the sentinel file.
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Causes \ ``pt-slave-restart``\ to create the sentinel file specified by
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"--sentinel". This should have the effect of stopping all running
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instances which are watching the same sentinel file. If "--monitor" isn't
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specified, \ ``pt-slave-restart``\ will exit after creating the file. If it is
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specified, \ ``pt-slave-restart``\ will wait the interval given by
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"--max-sleep", then remove the file and continue working.
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You might find this handy to stop cron jobs gracefully if necessary, or to
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replace one running instance with another. For example, if you want to stop
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and restart \ ``pt-slave-restart``\ every hour (just to make sure that it is
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restarted every hour, in case of a server crash or some other problem), you
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could use a \ ``crontab``\ line like this:
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.. code-block:: perl
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0 * * * * pt-slave-restart --monitor --stop --sentinel /tmp/pt-slave-restartup
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The non-default "--sentinel" will make sure the hourly \ ``cron``\ job stops
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only instances previously started with the same options (that is, from the
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same \ ``cron``\ job).
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See also "--sentinel".
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--until-master
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type: string
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Run until this master log file and position. Start the slave, and retry if it
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fails, until it reaches the given replication coordinates. The coordinates are
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the logfile and position on the master, given by relay_master_log_file,
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exec_master_log_pos. The argument must be in the format "file,pos". Separate
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the filename and position with a single comma and no space.
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This will also cause an UNTIL clause to be given to START SLAVE.
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After reaching this point, the slave should be stopped and pt-slave-restart
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will exit.
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--until-relay
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type: string
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Run until this relay log file and position. Like "--until-master", but in
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the slave's relay logs instead. The coordinates are given by relay_log_file,
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relay_log_pos.
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--user
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short form: -u; type: string
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User for login if not current user.
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--verbose
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short form: -v; cumulative: yes; default: 1
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Be verbose; can specify multiple times. Verbosity 1 outputs connection
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information, a timestamp, relay_log_file, relay_log_pos, and last_errno.
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Verbosity 2 adds last_error. See also "--error-length". Verbosity 3 prints
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the current sleep time each time pt-slave-restart sleeps.
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--version
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Show version and exit.
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***********
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DSN OPTIONS
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***********
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These DSN options are used to create a DSN. Each option is given like
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\ ``option=value``\ . The options are case-sensitive, so P and p are not the
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same option. There cannot be whitespace before or after the \ ``=``\ and
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if the value contains whitespace it must be quoted. DSN options are
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comma-separated. See the percona-toolkit manpage for full details.
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\* A
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dsn: charset; copy: yes
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Default character set.
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\* D
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dsn: database; copy: yes
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Default database.
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\* F
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dsn: mysql_read_default_file; copy: yes
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Only read default options from the given file
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\* h
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dsn: host; copy: yes
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Connect to host.
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\* p
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dsn: password; copy: yes
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Password to use when connecting.
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\* P
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dsn: port; copy: yes
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Port number to use for connection.
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\* S
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dsn: mysql_socket; copy: yes
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Socket file to use for connection.
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\* u
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dsn: user; copy: yes
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User for login if not current user.
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***********
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ENVIRONMENT
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***********
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The environment variable \ ``PTDEBUG``\ enables verbose debugging output to STDERR.
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To enable debugging and capture all output to a file, run the tool like:
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.. code-block:: perl
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PTDEBUG=1 pt-slave-restart ... > FILE 2>&1
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Be careful: debugging output is voluminous and can generate several megabytes
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of output.
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*******************
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SYSTEM REQUIREMENTS
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*******************
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You need Perl, DBI, DBD::mysql, and some core packages that ought to be
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installed in any reasonably new version of Perl.
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****
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BUGS
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****
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For a list of known bugs, see `http://www.percona.com/bugs/pt-slave-restart <http://www.percona.com/bugs/pt-slave-restart>`_.
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Please report bugs at `https://bugs.launchpad.net/percona-toolkit <https://bugs.launchpad.net/percona-toolkit>`_.
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Include the following information in your bug report:
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\* Complete command-line used to run the tool
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\* Tool "--version"
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\* MySQL version of all servers involved
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\* Output from the tool including STDERR
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\* Input files (log/dump/config files, etc.)
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If possible, include debugging output by running the tool with \ ``PTDEBUG``\ ;
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see "ENVIRONMENT".
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***********
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DOWNLOADING
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***********
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Visit `http://www.percona.com/software/percona-toolkit/ <http://www.percona.com/software/percona-toolkit/>`_ to download the
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latest release of Percona Toolkit. Or, get the latest release from the
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command line:
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.. code-block:: perl
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wget percona.com/get/percona-toolkit.tar.gz
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wget percona.com/get/percona-toolkit.rpm
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wget percona.com/get/percona-toolkit.deb
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You can also get individual tools from the latest release:
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.. code-block:: perl
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wget percona.com/get/TOOL
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Replace \ ``TOOL``\ with the name of any tool.
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*******
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AUTHORS
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*******
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Baron Schwartz
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*********************
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ABOUT PERCONA TOOLKIT
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*********************
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This tool is part of Percona Toolkit, a collection of advanced command-line
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tools developed by Percona for MySQL support and consulting. Percona Toolkit
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was forked from two projects in June, 2011: Maatkit and Aspersa. Those
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projects were created by Baron Schwartz and developed primarily by him and
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Daniel Nichter, both of whom are employed by Percona. Visit
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`http://www.percona.com/software/ <http://www.percona.com/software/>`_ for more software developed by Percona.
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********************************
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COPYRIGHT, LICENSE, AND WARRANTY
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********************************
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This program is copyright 2007-2011 Baron Schwartz, 2011 Percona Inc.
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Feedback and improvements are welcome.
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THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
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WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation, version 2; OR the Perl Artistic License. On UNIX and similar
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systems, you can issue \`man perlgpl' or \`man perlartistic' to read these
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licenses.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place, Suite 330, Boston, MA 02111-1307 USA.
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*******
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VERSION
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*******
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pt-slave-restart 1.0.2
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Loggerhead is a web-based interface for Breezy
Version: 2.0.1