mytop - display MySQL server performance info like `top'
The latest version of mytop
is available from
http://jeremy.zawodny.com/mysql/mytop/ it might
also be on CPAN as
In order for mytop
to function properly, you must have the following:
* Perl 5.005 or newer
* DBI and DBD::mysql
* Term::ReadKey from CPAN
Most systems are likely to have all of those installed--except for
Term::ReadKey. You will need to pick that up from the CPAN. You can pick up
And you obviously need access to a MySQL server (version 3.22.x or 3.23.x) with
the necessary security to run the SHOW PROCESSLIST
and SHOW GLOBAL
If you are a Windows user, using ActiveState's Perl, you can use PPM (the Perl
Package Manager) to install the MySQL and Term::ReadKey modules.
In additon, if you want a color mytop
Term::ANSIColor from the CPAN:
Once you do, mytop
will automatically use it. However, color is not yet
working on Windows. Patches welcome. :-)
If you want mytop
to provide more accurate real-time queries-per-second
statistics, install the Time::HiRes module from CPAN. mytop
automatically notice that you have it and use it rather than the standard
is known to work on:
* Linux (2.2.x, 2.4.x)
* FreeBSD (2.2, 3.x, 4.x)
* Mac OS X
* BSDI 4.x
* Solaris 2.x
* Windows NT 4.x (ActivePerl)
If you find that it works on another platform, please let me know. Given that it
is all Perl code, I expect it to be rather portable to Unix and Unix-like
systems. Heck, it might
even work on Win32 systems.
Help is always welcome in improving this software. Feel free to contact the
author (see "AUTHOR" below) with bug reports, fixes, suggestions,
and comments. Additionally "BUGS" will provide a list of things this
software is not able to do yet.
Having said that, here are the details on how it works and what you can do with
was inspired by the system monitoring tool top
. I routinely
on Linux, FreeBSD, and Solaris. You are likely to notice
features from each of them here.
will connect to a MySQL server and periodically run the SHOW
and SHOW GLOBAL STATUS
commands and attempt to
summarize the information from them in a useful format.
display screen is really broken into two parts. The top 4 lines
(header) contain summary information about your MySQL server. For example, you
might see something like:
MySQL on localhost (4.0.13-log) up 1+11:13:00 [23:29:11]
Queries: 19.3M qps: 160 Slow: 1.0 Se/In/Up/De(%): 00/80/03/17
qps now: 219 Slow qps: 0.0 Threads: 1 ( 1/ 16) 00/74/00/25
Key Efficiency: 99.3% Bps in/out: 30.5k/162.8 Now in/out: 32.7k/ 3.3k
The first line identifies the hostname of the server (localhost) and the version
of MySQL it is running. The right had side shows the uptime of the MySQL
server process in days+hours:minutes:seconds format (much like FreeBSD's top)
as well as the current time.
The second line displays the total number of queries the server has processed,
the average number of queries per second, the number of slow queries, and the
percentage of Select, Insert, Update, and Delete queries.
The third real-time values. First is the number of queries per second, then the
number of slow queries, followed by query precentages (like on the previous
And the fourth line displays key buffer efficiency (how often keys are read from
the buffer rather than disk) and the number of bytes that MySQL has sent and
received, both over all and in the last cycle.
You can toggle the header by hitting h
when running mytop
The second part of the display lists as many threads as can fit on screen. By
default they are sorted according to their idle time (least idle first). The
display looks like:
Id User Host Dbase Time Cmd Query or State
-- ---- ---- ----- ---- --- --------------
61 jzawodn localhost music 0 Query show processlist
As you can see, the thread id, username, host from which the user is connecting,
database to which the user is connected, number of seconds of idle time, the
command the thread is executing, and the query info are all displayed.
Often times the query info is what you are really interested in, so it is good
to run mytop
in an xterm that is wider than the normal 80 columns if
The thread display color-codes the threads if you have installed color support.
The current color scheme only works well in a window with a dark (like black)
background. The colors are selected according to the "Command"
column of the display:
Query - Yellow
Sleep - White
Connect - Green
Those are purely arbitrary and will be customizable in a future release. If they
annoy you just start mytop
with the -nocolor
flag or adjust your
config file appropriately.
handles long and short command-line arguments. Not all options have
both long and short formats, however. The long arguments can start with one or
two dashes `-' or `--'. They are shown here with just one.
- -u or -user username
- Username to use when logging in to the MySQL server. Default:
- -p or -pass or -password password
- Password to use when logging in to the MySQL server. Default: none.
- -h or -host hostname[:port]
- Hostname of the MySQL server. The hostname may be followed by an option
port number. Note that the port is specified separate from the host when
using a config file. Default: ``localhost''.
- -port or -P port
- If you're running MySQL on a non-standard port, use this to specify the
port number. Default: 3306.
- -s or -delay seconds
- How long between display refreshes. Default: 5
- -d or -db or -database database
- Use if you'd like mytop to connect to a specific database by
default. Default: ``test''.
- -b or -batch or -batchmode
- In batch mode, mytop runs only once, does not clear the screen, and places
no limit on the number of lines it will print. This is suitable for
running periodically (perhaps from cron) to capture the information into a
file for later viewing. You might use batch mode in a CGI script to
occasionally display your MySQL server status on the web.
- -S or -socket /path/to/socket
- If you're running mytop on the same host as MySQL, you may wish to
have it use the MySQL socket directly rather than a standard TCP/IP
connection. If you do,just specify one.
Note that specifying a socket will make mytop ignore any host and/or
port that you might have specified. If the socket does not exist (or the
file specified is not a socket), this option will be ignored and
mytop will use the hostname and port number instead.
- -header or -noheader
- Sepcify if you want the header to display or not. You can toggle this with
the h key while mytop is running.
- -color or -nocolor
- Specify if you want a color display. This has no effect if you don't have
color support available.
Default: If you have color support, mytop will try color unless you
tell it not to.
- -i or -idle or -noidle
- Specify if you want idle (sleeping) threads to appear in the list. If
sleeping threads are omitted, the default sorting order is reversed so
that the longest running queries appear at the top of the list.
- -prompt or -noprompt
- Specify if you want to be prompted to type in your database password. This
provides a little bit more security since it not only prevents the
password from viewable in a process list, but also doesn't require the
password to be stored in plain text in your ~/.mytop config file. You will
only be prompted if a password has not been specified in your
config file or through another command line option.
- If you have skip-resolve set on MySQL (to keep it from doing a reverse DNS
lookup on each inbound connection), mytop can replace IP addresses with
hostnames but toggling this option.
Command-line arguments will always take precedence over config file options.
That happens because the config file is read BEFORE
arguments are applied.
Instead of always using bulky command-line parameters, you can also use a config
file in your home directory ("~/.mytop"). If present, mytop
will read it automatically. It is read before
any of your command-line
arguments are processed, so your command-line arguments will override
directives in the config file.
Here is a sample config file "~/.mytop" which implements the defaults
Using a config file will help to ensure that your database password isn't
visible to users on the command-line. Just make sure that the permissions on
"~/.mytop" are such that others cannot read it (unless you want them
to, of course).
You may have white space on either side of the "=" in lines of the
The following keys perform various actions while mytop
is running. Those
which have not been implemented are listed as such. They are included to give
the user idea of what is coming.
- Display help.
- Show "command counters" based on the Com_* values in SHOW GLOBAL
STATUS. This is a new feature. Feedback welcome.
- Show only threads connected to a particular database.
- Given a thread id, display the entire query that thread was (and still may
- Disable all filtering (host, user, and db).
- Only show queries from a particular host.
- Toggle the header display. You can also specify either
"header=0" or "header=1" in your config file to set
the default behavior.
- Toggle the display of idle (sleeping) threads. If sleeping threads are
filtered, the default sorting order is reversed so that the longest
running queries appear at the top of the list.
- Switch to InnoDB Status mode. The output of "SHOW INNODB STATUS"
will be displayed every cycle. In a future version, this may actually
summarize that data rather than producing raw output.
- Kill a thread.
- Toggle modes. Currently this switches from `top' mode to `qps' (Queries
Per Second Mode). In this mode, mytop will write out one integer per
second. The number written reflects the number of queries executed by the
server in the previous one second interval.
More modes may be added in the future.
- Reverse the default sort order.
- Pause display.
- Quit mytop
- Reset the server's status counters via a FLUSH STATUS command.
- Change the sleep time (number of seconds between display refreshes).
- Show only threads owned by a giver user.
key has a command-line counterpart: -s
key has two command-line counterparts: -header
This is more of a BUGS + WishList.
Some performance information is not available when talking to a version 3.22.x
MySQL server. Additional information (about threads mostly) was added to the
output of SHOW STATUS
in MySQL 3.23.x and mytop
makes use of it.
If the information is not available, you will simply see zeros where the real
numbers should be.
Simply running this program will increase your overall counters (such as the
number of queries run). But you may or may not view that as a bug.
consumes too much CPU time when running (verified on older versions
of Linux and FreeBSD). It's likely a problem related to Term::ReadKey. I
haven't had time to investigate yet, so mytop
now automatically lowers
its priority when you run it. You may also think about running mytop
another workstation instead of your database server. However,
"mytop" on Solaris does not
have this problem. Newer versions
of Linux and FreeBSD seem to have fixed this.
You can't specify the maximum number of threads to list. If you have many
threads and a tall xterm, mytop
will always try to display as many as
it can fit.
The size of most of the columns in the display has a small maximum width. If you
have fairly long database/user/host names the display may appear odd. I have
no good idea as to how best to deal with that yet. Suggestions are welcome.
It'd be nice if you could just add mytop
configuration directives in your
"my.cnf" file instead of having a separate config file.
You should be able to specify the columns you'd like to see in the display and
the order in which they appear. If you only have one username that connects to
your database, it's probably not worth having the User column appear, for
mytop was developed and is maintained by Jeremy D. Zawodny (Jeremy@Zawodny.com).
If you wish to e-mail me regarding this software, PLEASE
subscribe to the
mailing list. See the mytop
homepage for details.
While I use this software in my job at Yahoo!, I am solely responsible for it.
Yahoo! does not necessarily support this software in any way. It is merely a
personal idea which happened to be very useful in my job.
If you hack Perl and grok MySQL, come work at Yahoo! Contact me for details. Or
just send me your resume. Er, unless we just had layoffs, in which case we're
not hiring. :-(
Please check the MySQL manual if you're not sure where some of the output of
is coming from.
Copyright (C) 2000-2001, Jeremy D. Zawodny.
Fix a bug. Add a feature. See your name here!
Many thanks go to these fine folks:
- Sami Ahlroos (firstname.lastname@example.org)
- Suggested the idle/noidle stuff.
- Jan Willamowius (email@example.com)
- Mirnor bug report. Documentation fixes.
- Alex Osipov (firstname.lastname@example.org)
- Long command-line options, Unix socket support.
- Stephane Enten (email@example.com)
- Suggested batch mode.
- Richard Ellerbrock (firstname.lastname@example.org)
- Bug reports and usability suggestions.
- William R. Mattil (email@example.com)
- Bug report about empty passwords not working.
- Benjamin Pflugmann (firstname.lastname@example.org)
- Suggested -P command-line flag as well as other changes.
- Justin Mecham <email@example.com>
- Suggested setting $0 to `mytop'.
- Thorsten Kunz <firstname.lastname@example.org>
- Provided a fix for cases when we try remove the domain name from the
display even if it is actually an IP address.
- Sasha Pachev <email@example.com>
- Provided the idea of real-time queries per second in the main
- Paul DuBois <firstname.lastname@example.org>
- Pointed out some option-handling bugs.
- Mike Wexler <email@example.com>
- Suggested that we don't mangle (normalize) whitespace in query info by
- Mark Zweifel <firstname.lastname@example.org>
- Make the --idle command-line argument negatable.
- Axel Schwenke <email@example.com>
- Noticed the inccorect formula for query cache hit percentages in version
- Steven Roussey <firstname.lastname@example.org>
- Supplied a patch to help filter binary junk in queries so that terminals
don't freak out.
- jon r. luini <email@example.com>
- Supplied a patch that formed the basis for "-prompt" support.
Sean Leach <firstname.lastname@example.org> submitted a similar patch.
- Yogish Baliga <email@example.com>
- Supplied a patch that formed the basis for "-resolve"
- Per Andreas Buer <firstname.lastname@example.org>
- Supplied an excellent patch to tidy up the top display. This includes
showing most values in short form, such as 10k rather than 10000.
See the Changes file on the mytop
distribution page for more details on
what has changed.
is licensed under the GNU General Public License version 2. For the
full license information, please visit