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PT-SLAVE-DELAY(1)     User Contributed Perl Documentation    PT-SLAVE-DELAY(1)

       pt-slave-delay -	Make a MySQL slave server lag behind its master.

       Usage: pt-slave-delay [OPTIONS] SLAVE_DSN [MASTER_DSN]

       pt-slave-delay starts and stops a slave server as needed	to make	it lag
       behind the master.  The SLAVE_DSN and MASTER_DSN	use DSN	syntax,	and
       values are copied from the SLAVE_DSN to the MASTER_DSN if omitted.

       To hold slavehost one minute behind its master for ten minutes:

	  pt-slave-delay --delay 1m --interval 15s --run-time 10m slavehost

       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,	please:

       o   Read	the tool's documentation

       o   Review the tool's known "BUGS"

       o   Test	the tool on a non-production server

       o   Backup your production server and verify the	backups

       "pt-slave-delay"	watches	a slave	and starts and stops its replication
       SQL thread as necessary to hold it at least as far behind the master as
       you request.  In	practice, it will typically cause the slave to lag
       between "--delay" and "--delay"+"--interval" behind the master.

       It bases	the delay on binlog positions in the slave's relay logs	by
       default,	so there is no need to connect to the master.  This works well
       if the IO thread	doesn't	lag the	master much, which is typical in most
       replication setups; the IO thread lag is	usually	milliseconds on	a fast
       network.	 If your IO thread's lag is too	large for your purposes,
       "pt-slave-delay"	can also connect to the	master for information about
       binlog positions.

       If the slave's I/O thread reports that it is waiting for	the SQL	thread
       to free some relay log space, "pt-slave-delay" will automatically
       connect to the master to	find binary log	positions.  If "--ask-pass"
       and "--daemonize" are given, it is possible that	this could cause it to
       ask for a password while	daemonized.  In	this case, it exits.
       Therefore, if you think your slave might	encounter this condition, you
       should be sure to either	specify	"--use-master" explicitly when
       daemonizing, or don't specify "--ask-pass".

       The SLAVE_DSN and optional MASTER_DSN are both DSNs.  See "DSN
       OPTIONS".  Missing MASTER_DSN values are	filled in with values from
       SLAVE_DSN, so you don't need to specify them in both places.
       "pt-slave-delay"	reads all normal MySQL option files, such as
       ~/.my.cnf, so you may not need to specify username, password and	other
       common options at all.

       "pt-slave-delay"	tries to exit gracefully by trapping signals such as
       Ctrl-C.	You cannot bypass "--[no]continue" with	a trappable signal.

       pt-slave-delay requires the following privileges: PROCESS, REPLICATION
       CLIENT, and SUPER.

       If you specify "--quiet", there is no output.  Otherwise, the normal
       output is a status message consisting of	a timestamp and	information
       about what "pt-slave-delay" is doing: starting the slave, stopping the
       slave, or just observing.

       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.

	   default: yes

	   Continue replication	normally on exit.  After exiting, restart the
	   slave's SQL thread with no UNTIL condition, so it will run as usual
	   and catch up	to the master.	This is	enabled	by default and works
	   even	if you terminate "pt-slave-delay" with Control-C.

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

	   short form: -D; type: string

	   The database	to use for the connection.

	   short form: -F; type: string

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

	   type: time; default:	1h

	   How far the slave should lag	its master.

	   Show	help and exit.

	   short form: -h; type: string

	   Connect to host.

	   type: time; default:	1m

	   How frequently "pt-slave-delay" should check	whether	the slave
	   needs to be started or stopped.

	   type: string

	   Print all output to this file when daemonized.

	   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

	   Don't print informational messages about operation.	See OUTPUT for

	   type: time

	   How long "pt-slave-delay" should run	before exiting.	 The default
	   is to run forever.

	   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

	   short form: -S; type: string

	   Socket file to use for connection.

	   Get binlog positions	from master, not slave.	 Don't trust the
	   binlog positions in the slave's relay log.  Connect to the master
	   and get binlog positions instead.  If you specify this option
	   without giving a MASTER_DSN on the command line, "pt-slave-delay"
	   examines the	slave's	SHOW SLAVE STATUS to determine the hostname
	   and port for	connecting to the master.

	   "pt-slave-delay" uses only the MASTER_HOST and MASTER_PORT values
	   from	SHOW SLAVE STATUS for the master connection.  It does not use
	   the MASTER_USER value.  If you want to specify a different username
	   for the master than the one you use to connect to the slave,	you
	   should specify the MASTER_DSN option	explicitly on the command

	   short form: -u; type: string

	   User	for login if not current user.

	   Show	version	and exit.

	   default: yes

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

	   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 Perconaas 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 time.

	   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.

       o   A

	   dsn:	charset; copy: yes

	   Default character set.

       o   D

	   dsn:	database; copy:	yes

	   Default database.

       o   F

	   dsn:	mysql_read_default_file; copy: yes

	   Only	read default options from the given file

       o   h

	   dsn:	host; copy: yes

	   Connect to host.

       o   p

	   dsn:	password; copy:	yes

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

       o   P

	   dsn:	port; copy: yes

	   Port	number to use for connection.

       o   S

	   dsn:	mysql_socket; copy: yes

	   Socket file to use for connection.

       o   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-delay ... > 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:

       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.)

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

       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.

       Sergey Zhuravlev	and 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 Sergey	Zhuravle and Baron Schwartz.


       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-delay 3.2.0

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

       Around line 4825:
	   Non-ASCII character seen before =encoding in	'Perconaas'. Assuming

perl v5.32.1			  2020-04-23		     PT-SLAVE-DELAY(1)


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