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March 28, 2019

MySQL mysqld_multi utility commands

MySQL mysqld_multi utility examples

mysqld_multi --help
mysqld_multi [options] {start|stop|report} [GNR[,GNR] ...]
Usage: mysqld_multi [OPTIONS] {start|reload|stop|report} [GNR,GNR,GNR...]  or     
   mysqld_multi [OPTIONS] {start|reload|stop|report} [GNR-GNR,GNR,GNR-GNR,...]

mysqld_multi start 17
mysqld_multi stop 8,10-13

mysqld_multi can be used to start, reload, or stop any number of separate mysqld processes running in different TCP/IP ports and UNIX sockets.

mysqld_multi can read group [mysqld_multi] from my.cnf file. You may want to put options mysqld=... and mysqladmin=... there.  Since version 2.10 these options can also be given under groups [mysqld#], which gives more control over different versions.  One can have the default mysqld and mysqladmin under group [mysqld_multi], but this is not mandatory. Please note that if mysqld or mysqladmin is missing from both [mysqld_multi] and [mysqld#], a group that is tried to be used, mysqld_multi will abort with an error.

mysqld_multi will search for groups named [mysqld#] from my.cnf (or the given --defaults-extra-file=...), where '#' can be any positive integer starting from 1. These groups should be the same as the regular [mysqld] group, but with those port, socket and any other options that are to be used with each separate mysqld process. The number in the group name has another function; it can be used for starting, reloading, stopping, or reporting any specific mysqld server.

The GNR means the group number. You can start, reload, stop or report any GNR, or several of them at the same time. (See --example) The GNRs list can be comma separated or a dash combined. The latter means that all the GNRs between GNR1-GNR2 will be affected. Without GNR argument all the groups found will either be started, reloaded, stopped, or reported. Note that syntax for specifying GNRs must appear without spaces.

mysqld multi options:
These options must be given before any others:
--no-defaults      Do not read any defaults file
--defaults-file=...  Read only this configuration file, do not read the standard system-wide and user-specific files
--defaults-extra-file=...  Read this configuration file in addition to the  standard system-wide and user-specific files Using:

--example          Give an example of a config file with extra information.
--help              Print this help and exit.
--log=...          Log file. Full path to and the name for the log file. NOTE: If the file exists, everything will be appended. Using:

--mysqladmin=...   mysqladmin binary to be used for a server shutdown. Since version 2.10 this can be given within groups [mysqld#] Using:
--mysqld=...       mysqld binary to be used. Note that you can give mysqld_safe
to this option also. The options are passed to mysqld. Just make sure you have mysqld in your PATH or fix mysqld_safe. Using: Please note: Since mysqld_multi version 2.3 you can also give this option inside groups [mysqld#] in ~/.my.cnf, where '#' stands for an integer (number) of the group in question. This will be recognised as a special option and will not be passed to the mysqld. This will allow one to start different mysqld versions with mysqld_multi.

--no-log           Print to stdout instead of the log file. By default the log file is turned on.
--password=...     Password for mysqladmin user.
--silent           Disable warnings.
--tcp-ip           Connect to the MySQL server(s) via the TCP/IP port instead of the UNIX socket. This affects stopping and reporting.
                   If a socket file is missing, the server may still be running, but can be accessed only via the TCP/IP port. By default connecting is done via the UNIX socket.

--user=...          mysqladmin user. Using: root
--verbose         Be more verbose.
--version          Print the version number and exit.

Related MySQL Articles: mysqlcheck utility cheatsheet  mysqlindexcheck utility commands in MySQL

1 comment:

  1. Great Post,really it was very helpful for us.
    Thanks a lot for sharing!
    I found this blog to be very useful!!
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