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


       pt-slave-restart - Watch and restart MySQL replication after errors.


       Usage: pt-slave-restart [OPTIONS] [DSN]

       pt-slave-restart watches one or more MySQL replication slaves for errors, and tries to
       restart replication if it stops.


       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-slave-restart watches one or more MySQL replication slaves and tries to skip statements
       that cause errors.  It polls slaves intelligently with an exponentially varying sleep
       time.  You can specify errors to skip and run the slaves until a certain binlog position.

       Although this tool can help a slave advance past errors, you should not rely on it to
       "fix" replication.  If slave errors occur frequently or unexpectedly, you should identify
       and fix the root cause.


       pt-slave-restart prints a line every time it sees the slave has an error.  By default this
       line is: a timestamp, connection information, relay_log_file, relay_log_pos, and
       last_errno.  You can add more information using the "--verbose" option.  You can suppress
       all output using the "--quiet" option.


       pt-slave-restart sleeps intelligently between polling the slave.  The current sleep time

       ·   The initial sleep time is given by "--sleep".

       ·   If it checks and finds an error, it halves the previous sleep time.

       ·   If it finds no error, it doubles the previous sleep time.

       ·   The sleep time is bounded below by "--min-sleep" and above by "--max-sleep".

       ·   Immediately after finding an error, pt-slave-restart assumes another error is very
           likely to happen next, so it sleeps the current sleep time or the initial sleep time,
           whichever is less.


       As of Percona Toolkit 2.2.8, pt-slave-restart supports Global Transaction IDs introduced
       in MySQL 5.6.5.  It's important to keep in mind that:

       ·   pt-slave-restart will not skip transactions when multiple replication threads are
           being used (slave_parallel_workers > 0).  pt-slave-restart does not know what the GTID
           event is of the failed transaction of a specific slave thread.

       ·   The default behavior is to skip the next transaction from the slave's master.  Writes
           can originate on different servers, each with their own UUID.

           See "--master-uuid".


       An exit status of 0 (sometimes also called a return value or return code) indicates
       success.  Any other value represents the exit status of the Perl process itself, or of the
       last forked process that exited if there were multiple servers to monitor.


       pt-slave-restart should work on many versions of MySQL.  Lettercase of many output columns
       from SHOW SLAVE STATUS has changed over time, so it treats them all as lowercase.


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

           Start slaves even when there is no error.  With this option enabled, pt-slave-restart
           will not let you stop the slave manually if you want to!

           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.

           default: yes

           Check the last relay log file and position before checking for slave errors.

           By default pt-slave-restart will not doing anything (it will just sleep) if neither
           the relay log file nor the relay log position have changed since the last check.  This
           prevents infinite loops (i.e. restarting the same error in the same relay log file at
           the same relay log position).

           For certain slave errors, however, this check needs to be disabled by specifying
           "--no-check-relay-log".  Do not do this unless you know what you are doing!

           type: Array

           Read this comma-separated list of config files; if specified, this must be the first
           option on the command line.

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

           short form: -D; type: string

           Database to use.

           short form: -F; type: string

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

           type: int

           Max length of error message to print.  When "--verbose" is set high enough to print
           the error, this option will truncate the error text to the specified length.  This can
           be useful to prevent wrapping on the terminal.

           type: hash

           Only restart this comma-separated list of errors.  Makes pt-slave-restart only try to
           restart if the error number is in this comma-separated list of errors.  If it sees an
           error not in the list, it will exit.

           The error number is in the "last_errno" column of "SHOW SLAVE STATUS".

           type: string

           Only restart errors that match this pattern.  A Perl regular expression against which
           the error text, if any, is matched.  If the error text exists and matches, pt-slave-
           restart will try to restart the slave.  If it exists but doesn't match, pt-slave-
           restart will exit.

           The error text is in the "last_error" column of "SHOW SLAVE STATUS".

           Show help and exit.

           short form: -h; type: string

           Connect to host.

           type: string

           Print all output to this file when daemonized.

           type: float; default: 64

           Maximum sleep seconds.

           The maximum time pt-slave-restart will sleep before polling the slave again.  This is
           also the time that pt-slave-restart will wait for all other running instances to quit
           if both "--stop" and "--monitor" are specified.

           See "SLEEP".

           type: float; default: 0.015625

           The minimum time pt-slave-restart will sleep before polling the slave again.  See

           Whether to monitor the slave (default).  Unless you specify --monitor explicitly,
           "--stop" will disable it.

           short form: -p; type: string

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

           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.

           short form: -q

           Suppresses normal output (disables "--verbose").

           type: int; default: 0

           Watch slaves of the specified server, up to the specified number of servers deep in
           the hierarchy.  The default depth of 0 means "just watch the slave specified."

           pt-slave-restart examines "SHOW PROCESSLIST" and tries to determine which connections
           are from slaves, then connect to them.  See "--recursion-method".

           Recursion works by finding all slaves when the program starts, then watching them.  If
           there is more than one slave, "pt-slave-restart" uses "fork()" to monitor them.

           This also works if you have configured your slaves to show up in "SHOW SLAVE HOSTS".
           The minimal configuration for this is the "report_host" parameter, but there are other
           "report" parameters as well for the port, username, and password.

           type: array; default: processlist,hosts

           Preferred recursion method used to find slaves.

           Possible methods are:

             METHOD       USES
             ===========  ==================
             processlist  SHOW PROCESSLIST
             hosts        SHOW SLAVE HOSTS
             none         Do not find slaves

           The processlist method is preferred because SHOW SLAVE HOSTS is not reliable.
           However, the hosts method is required if the server uses a non-standard port (not
           3306).  Usually pt-slave-restart does the right thing and finds the slaves, but you
           may give a preferred method and it will be used first.  If it doesn't find any slaves,
           the other methods will be tried.

           type: time

           Time to run before exiting.  Causes pt-slave-restart to stop after the specified time
           has elapsed.  Optional suffix: s=seconds, m=minutes, h=hours, d=days; if no suffix, s
           is used.

           type: string; default: /tmp/pt-slave-restart-sentinel

           Exit if this file exists.

           type: string

           Sets the user to be used to connect to the slaves.  This parameter allows you to have
           a different user with less privileges on the slaves but that user must exist on all

           type: string

           Sets the password to be used to connect to the slaves.  It can be used with
           --slave-user and the password for the user must be the same on all slaves.

           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.

           type: int; default: 1

           Number of statements to skip when restarting the slave.

           type: string

           When using GTID, an empty transaction should be created in order to skip it.  If
           writes are coming from different nodes in the replication tree above, it is not
           possible to know which event from which UUID to skip.

           By default, transactions from the slave's master ('Master_UUID' from "SHOW SLAVE
           STATUS") are skipped.

           For example, with

             master1 -> slave1 -> slave2

           When skipping events on slave2 that were written to master1, you must specify the UUID
           of master1, else the tool will use the UUID of slave1 by default.


           type: int; default: 1

           Initial sleep seconds between checking the slave.

           See "SLEEP".

           short form: -S; type: string

           Socket file to use for connection.

           Stop running instances by creating the sentinel file.

           Causes "pt-slave-restart" to create the sentinel file specified by "--sentinel".  This
           should have the effect of stopping all running instances which are watching the same
           sentinel file.  If "--monitor" isn't specified, "pt-slave-restart" will exit after
           creating the file.  If it is specified, "pt-slave-restart" will wait the interval
           given by "--max-sleep", then remove the file and continue working.

           You might find this handy to stop cron jobs gracefully if necessary, or to replace one
           running instance with another.  For example, if you want to stop and restart
           "pt-slave-restart" every hour (just to make sure that it is restarted every hour, in
           case of a server crash or some other problem), you could use a "crontab" line like

            0 * * * * pt-slave-restart --monitor --stop --sentinel /tmp/pt-slave-restartup

           The non-default "--sentinel" will make sure the hourly "cron" job stops only instances
           previously started with the same options (that is, from the same "cron" job).

           See also "--sentinel".

           type: string

           Run until this master log file and position.  Start the slave, and retry if it fails,
           until it reaches the given replication coordinates.  The coordinates are the logfile
           and position on the master, given by relay_master_log_file, exec_master_log_pos.  The
           argument must be in the format "file,pos".  Separate the filename and position with a
           single comma and no space.

           This will also cause an UNTIL clause to be given to START SLAVE.

           After reaching this point, the slave should be stopped and pt-slave-restart will exit.

           type: string

           Run until this relay log file and position.  Like "--until-master", but in the slave's
           relay logs instead.  The coordinates are given by relay_log_file, relay_log_pos.

           short form: -u; type: string

           User for login if not current user.

           short form: -v; cumulative: yes; default: 1

           Adds more information to the output.  This flag can be specified multiple times. e.g.
           -v -v OR -vv.  By default (no verbose flag) the tool outputs connection information, a
           timestamp, relay_log_file, relay_log_pos, and last_errno.  One flag (-v) adds
           last_error.  See also "--error-length".  Two flags (-vv) prints the current sleep time
           each time pt-slave-restart sleeps.  To suppress all output use the "--quiet" option.

           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

       Show version and exit.


       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-slave-restart ... > 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


       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, 2007-2011 Baron


       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-slave-restart 3.0.13


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