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pt-replica-find

NAME

pt-replica-find - Find and print replication hierarchy tree of MySQL replicas.

SYNOPSIS

Usage

pt-replica-find [OPTIONS] [DSN]

pt-replica-find finds and prints a hierarchy tree of MySQL replicas.

Examples

pt-replica-find --host source-host

RISKS

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:

  • 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

DESCRIPTION

pt-replica-find connects to a MySQL replication source and finds its replicas. Currently the only thing it can do is print a tree-like view of the replication hierarchy.

The source host can be specified using one of two methods. The first method is to use the standard connection-related command line options: --defaults-file, --password, --host, --port, --socket or --user.

The second method to specify the source host is a DSN. A DSN is a special syntax that can be either just a hostname (like server.domain.com or 1.2.3.4), or a key=value,key=value string. Keys are a single letter:

KEY MEANING
=== =======
h   Connect to host
P   Port number to use for connection
S   Socket file to use for connection
u   User for login if not current user
p   Password to use when connecting
F   Only read default options from the given file

pt-replica-find 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.

EXIT STATUS

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.

OPTIONS

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 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.

--config

type: Array

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

--database

type: string; short form: -D

Database to use.

--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.

--password

short form: -p; type: string

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

--pid

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.

--port

short form: -P; type: int

Port number to use for connection.

--recurse

type: int

Number of levels to recurse in the hierarchy. Default is infinite.

See --recursion-method.

--recursion-method

type: array; default: processlist,hosts

Preferred recursion method used to find replicas.

Possible methods are:

METHOD       USES
===========  ==================
processlist  SHOW PROCESSLIST
hosts        SHOW REPLICAS (SHOW SLAVE HOSTS before MySQL 8.1)
none         Do not find replicas

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

--report-format

type: string; default: summary

Set what information about the replicas is printed. The report format can be one of the following:

  • hostname

Print just the hostname name of the replicas. It looks like:

127.0.0.1:12345
+- 127.0.0.1:12346
   +- 127.0.0.1:12347

  • summary

Print a summary of each replica’s settings. This report shows more information about each replica, like:

127.0.0.1:12345
Version         5.1.34-log
Server ID       12345
Uptime          04:56 (started 2010-06-17T11:21:22)
Replication     Is not a replica, has 1 replicas connected
Filters
Binary logging  STATEMENT
Slave status
Slave mode      STRICT
Auto-increment  increment 1, offset 1
+- 127.0.0.1:12346
   Version         5.1.34-log
   Server ID       12346
   Uptime          04:54 (started 2010-06-17T11:21:24)
   Replication     Is a replica, has 1 replicas connected
   Filters
   Binary logging  STATEMENT
   Slave status    0 seconds behind, running, no errors
   Slave mode      STRICT
   Auto-increment  increment 1, offset 1
--resolve-address

Resolve ip-address to hostname. Report will print both IP and hostname.

Example:

10.10.7.14 (dbase1.sample.net)

Might delay runtime a few seconds.

--slave-user

type: string

This option is deprecated and will be removed in future releases. Use --replica-user instead.

--slave-password

type: string

This option is deprecated and will be removed in future releases. Use --replica-password instead.

--replica-user

type: string

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

--replica-password

type: string

Sets the password to be used to connect to the replicas. It can be used with –replica-user and the password for the user must be the same on all replicas.

--set-vars

type: Array

Set the MySQL variables in this comma-separated list of variable=value pairs.

By default, the tool sets:

wait_timeout=10000

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

User for login if not current user.

--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. 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.

  • s

dsn: mysql_ssl; copy: yes

Create SSL connection

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:

PTDEBUG=1 pt-replica-find ... > FILE 2>&1

Be careful: debugging output is voluminous and can generate several megabytes of output.

ATTENTION

Using <PTDEBUG> might expose passwords. When debug is enabled, all command line parameters are shown in the 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 https://jira.percona.com/projects/PT/issues.

Please report bugs at https://jira.percona.com/projects/PT. 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 “ENVIRONMENT”.

DOWNLOADING

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:

wget percona.com/get/percona-toolkit.tar.gz

wget percona.com/get/percona-toolkit.rpm

wget percona.com/get/percona-toolkit.deb

You can also get individual tools from the latest release:

wget percona.com/get/TOOL

Replace TOOL with the name of any tool.

AUTHORS

Baron Schwartz and Daniel Nichter

ABOUT PERCONA TOOLKIT

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.

VERSION

pt-replica-find 3.7.0