5.18 mysqlrplshow — Show Slaves for Master Server

This utility shows the replication slaves for a master. It prints a graph of the master and its slaves labeling each with the host name and port number.

You must specify the --discover-slaves-login option to provide the user name and password to discover any slaves in the topology.

To explore the slaves for each client, use the --recurse option. This causes the utility to connect to each slave found and attempt to determine whether it has any slaves. If slaves are found, the process continues until the slave is found in the list of servers serving as masters (a circular topology). The graph displays the topology with successive indents. A notation is made for circular topologies.

If you use the --recurse option, the utility attempts to connect to the slaves using the user name and password provided for the master. By default, if the connection attempt fails, the utility throws an error and stops. To change this behavior, use the --prompt option, which permits the utility to prompt for the user name and password for each slave that fails to connect. You can also use the --num-retries=n option to reattempt a failed connection 'n' times before the utility fails.

An example graph for a typical topology with relay slaves is shown here:

# Replication Topology Graph::

localhost:3311 (MASTER)
   |
   +--- localhost:3310 - (SLAVE)
   |
   +--- localhost:3312 - (SLAVE + MASTER)
       |
       +--- localhost:3313 - (SLAVE)

MASTER, SLAVE, and SLAVE+MASTER indicate that a server is a master only, slave only, and both slave and master, respectively.

A circular replication topology is shown like this, where <--> indicates circularity:

# Replication Topology Graph

localhost:3311 (MASTER)
   |
   +--- localhost:3312 - (SLAVE + MASTER)
       |
       +--- localhost:3313 - (SLAVE + MASTER)
           |
           +--- localhost:3311 <--> (SLAVE)

To produce a column list in addition to the graph, specify the --show-list option. In this case, to specify how to display the list, use one of the following values with the --format option:

The utility uses of the SHOW SLAVE HOSTS statement to determine which slaves the master has. If you want to use the --recurse option, slaves should have been started with the --report-host and --report-port options set to their actual host name and port number or the utility may not be able to connect to the slaves to determine their own slaves.

OPTIONS

mysqlrplshow accepts the following command-line options:

NOTES

The login user must have the REPLICATE SLAVE and REPLICATE CLIENT privileges to successfully execute this utility. Specifically, the login user must have appropriate permissions to execute SHOW SLAVE STATUS, SHOW MASTER STATUS, and SHOW SLAVE HOSTS.

For the --format option, the permitted values are not case sensitive. In addition, values may be specified as any unambiguous prefix of a valid value. For example, --format=g specifies the grid format. An error occurs if a prefix matches more than one valid value.

Mixing IP and hostnames is not recommended. The replication-specific utilities will attempt to compare hostnames and IP addresses as aliases for checking slave connectivity to the master. However, if your installation does not support reverse name lookup, the comparison could fail. Without the ability to do a reverse name lookup, the replication utilities could report a false negative that the slave is (not) connected to the master.

For example, if you setup replication using MASTER_HOST=ubuntu.net on the slave and later connect to the slave with mysqlrplcheck and have the master specified as --master=192.168.0.6 using the valid IP address for ubuntu.net, you must have the ability to do a reverse name lookup to compare the IP (192.168.0.6) and the hostname (ubuntu.net) to determine if they are the same machine.

The path to the MySQL client tools should be included in the PATH environment variable in order to use the authentication mechanism with login-paths. This will allow the utility to use the my_print_defaults tools which is required to read the login-path values from the login configuration file (.mylogin.cnf).

EXAMPLES

To show the slaves for a master running on port 3311 on the local host, use the following command:

shell> mysqlrplshow  --master=root@localhost:3311 --discover-slaves-login=root
# master on localhost: ... connected.
# Finding slaves for master: localhost:3311

# Replication Topology Graph
localhost:3311 (MASTER)
   |
   +--- localhost:3310 - (SLAVE)
   |
   +--- localhost:3312 - (SLAVE)

As shown in the example, you must provide valid login information for the master.

To show additional information about the IO thread status (to confirm if the slaves are really connected to the master) use the option --verbose:

shell> mysqlrplshow  --master=root@localhost:3311 --discover-slaves-login=root --verbose
# master on localhost: ... connected.
# Finding slaves for master: localhost:3311

# Replication Topology Graph
localhost:3311 (MASTER)
   |
   +--- localhost:3310 [IO: Yes, SQL: Yes] - (SLAVE)
   |
   +--- localhost:3312 [IO: Yes, SQL: Yes] - (SLAVE)

To show the full replication topology of a master running on the local host, use the following command:

shell> mysqlrplshow  --master=root@localhost:3311 --recurse --discover-slaves-login=root
# master on localhost: ... connected.
# Finding slaves for master: localhost:3311

# Replication Topology Graph
localhost:3311 (MASTER)
   |
   +--- localhost:3310 - (SLAVE)
   |
   +--- localhost:3312 - (SLAVE + MASTER)
       |
       +--- localhost:3313 - (SLAVE)

To show the full replication topology of a master running on the local host, prompting for the user name and password for slaves that do not have the same user name and password credentials as the master, use the following command:

shell> mysqlrplshow --recurse --prompt --num-retries=1 \
          --master=root@localhost:3331 --discover-slaves-login=root

Server localhost:3331 is running on localhost.
# master on localhost: ... connected.
# Finding slaves for master: localhost:3331
Server localhost:3332 is running on localhost.
# master on localhost: ... FAILED.
Connection to localhost:3332 has failed.
Please enter the following information to connect to this server.
User name: root
Password:
# master on localhost: ... connected.
# Finding slaves for master: localhost:3332
Server localhost:3333 is running on localhost.
# master on localhost: ... FAILED.
Connection to localhost:3333 has failed.
Please enter the following information to connect to this server.
User name: root
Password:
# master on localhost: ... connected.
# Finding slaves for master: localhost:3333
Server localhost:3334 is running on localhost.
# master on localhost: ... FAILED.
Connection to localhost:3334 has failed.
Please enter the following information to connect to this server.
User name: root
Password:
# master on localhost: ... connected.
# Finding slaves for master: localhost:3334

# Replication Topology Graph
localhost:3331 (MASTER)
   |
   +--- localhost:3332 - (SLAVE)
   |
   +--- localhost:3333 - (SLAVE + MASTER)
       |
       +--- localhost:3334 - (SLAVE)

PERMISSIONS REQUIRED

The user connected to the master must have the REPLICATION SLAVE privilege.

The user specified with the --discover-slaves-login option that logs into each slave must have the REPLICATION CLIENT privilege.