Section: User Contributed Perl Documentation (1)
mytop - display MySQL server performance info like `top'
The latest version of mytop
is available from
also be on CPAN
In order for mytop
to function properly, you must have the
* 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 Term::ReadKey here:
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 STATUS commands.
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
Optional Color Support
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. :-)
Optional Hi-Res Timing
If you want mytop
to provide more accurate real-time
queries-per-second statistics, install the Time::HiRes module from
will automatically notice that you have it and use it
rather than the standard timing mechanism.
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
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 it.
was inspired by the system monitoring tool top
routinely use top
on Linux, FreeBSD, and Solaris. You are likely to
notice features from each of them here.
mytop will connect to a MySQL server and periodically run the
SHOW PROCESSLIST 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
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 line).
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 possible.
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
- -u or -user username
Username to use when logging in to the MySQL server. Default: ``root''.
- -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
- -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 the
command-line 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,
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
running. Those which have not been implemented are listed as
such. They are included to give the user idea of what is coming.
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 be) running.
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.
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.
The s key has a command-line counterpart: -s.
The h key has two command-line counterparts: -header and
This is more of a BUGS +
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
mytop 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 on 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 example.
mytop was developed and is maintained by Jeremy D. Zawodny
If you wish to e-mail me regarding this software, PLEASE subscribe
to the mytop 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
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 mytop
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 (email@example.com)
Suggested the idle/noidle stuff.
- Jan Willamowius (firstname.lastname@example.org)
Mirnor bug report. Documentation fixes.
- Alex Osipov (email@example.com)
Long command-line options, Unix socket support.
- Stephane Enten (firstname.lastname@example.org)
Suggested batch mode.
- Richard Ellerbrock (email@example.com)
Bug reports and usability suggestions.
- William R. Mattil (firstname.lastname@example.org)
Bug report about empty passwords not working.
- Benjamin Pflugmann (email@example.com)
Suggested -P command-line flag as well as other changes.
- Justin Mecham <firstname.lastname@example.org>
Suggested setting $0 to `mytop'.
- Thorsten Kunz <email@example.com>
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 <firstname.lastname@example.org>
Provided the idea of real-time queries per second in the main display.
- Paul DuBois <email@example.com>
Pointed out some option-handling bugs.
- Mike Wexler <firstname.lastname@example.org>
Suggested that we don't mangle (normalize) whitespace in query info by
- Mark Zweifel <email@example.com>
Make the --idle command-line argument negatable.
- Axel Schwenke <firstname.lastname@example.org>
Noticed the inccorect formula for query cache hit percentages in
- Steven Roussey <email@example.com>
Supplied a patch to help filter binary junk in queries so that
terminals don't freak out.
- jon r. luini <firstname.lastname@example.org>
Supplied a patch that formed the basis for "-prompt" support. Sean
Leach <email@example.com> submitted a similar patch.
- Yogish Baliga <firstname.lastname@example.org>
Supplied a patch that formed the basis for "-resolve" support.
- Per Andreas Buer <email@example.com>
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