pgtop - display PostgreSQL performance info like `top'
The latest version of pgtop is available from https://metacpan.org/author/COSIMO or on github at https://github.com/cosimo/pgtop.
In order for pgtop to function properly, you must have the following:
* Perl 5.014 or newer
* DBI and DBD::Pg
Most systems are likely to have all of those installed or readily available.
And you obviously need access to a PostgreSQL server (version 7.2+) with the necessary security to access the pg_stat* relations.
In additon, if you want a color mytop (recommended), install Term::ANSIColor from the CPAN:
Once you do, pgtop will automatically use it. However, color is not yet working on Windows. Patches welcome. :-)
If you want pgtop to provide more accurate real-time queries-per-second statistics, install the Time::HiRes module from CPAN. pgtop will automatically notice that you have it and use it rather than the standard timing mechanism.
pgtop currently is known to work only on Linux. Its `mytop' brother, however, has been reported 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 us 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 it.
pgtop was inspired by mytop (http://mytop.sourceforge.net/), which in turn was inspired by the system monitoring tool top.
pgtop will connect to a PostgreSQL server and periodically run queries against the pg_stat* relations and attempt to summarize the information from them in a useful format.
What you read from now on has not been revised, and refers to the original utility mytop.
The mytop 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 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.
mytop 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.
Username to use when logging in to the MySQL server. Default: ``root''.
Password to use when logging in to the MySQL server. Default: none.
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''.
If you're running MySQL on a non-standard port, use this to specify the port number. Default: 3306.
How long between display refreshes. Default: 5
Use if you'd like mytop to connect to a specific database by default. Default: ``test''.
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.
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.
Sepcify if you want the header to display or not. You can toggle this with the h key while mytop is running.
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.
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.
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.
Defines the threshold in seconds after which a query must be considered slow and it's logged to a file (`pgtop.log`).
If provided, in the form of a slack incoming webhook URL (e.g. https://hooks.slack.com/services/...), it will be used to send notifications for queries that are running longer than slow_threshold seconds.
There is no default value, so no slack notification will be sent if this parameter is not provided.
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 (~/.pgtop). If present, pgtop 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 ~/.pgtop which implements the defaults described above.
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 ~/.pgtop 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 config file.
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.
Show "command counters" based on the Com_* values in SHOW 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.
Kill a thread.
Kill all threads/queries that have been running for longer than a given threshold in seconds.
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 -noheader.
Probably many, but pgtop is still quite useful.
pgtop was adapted from mytop and is maintained by Cosimo Streppone (firstname.lastname@example.org).
mytop was developed and is maintained by Jeremy D. Zawodny (Jeremy@Zawodny.com).
If you wish to e-mail me regarding this software, please do!
This is certainly not a quality work, but before this crap, there was nothing but pg_stat_* tables. Just like Jeremy, I needed something more immediate and usable, like top.
To tell the real truth, I didn't even know about pg_stat tables. :-)
There is huge room for improvement!
Copyright (C) 2005-2020, Cosimo Streppone. Copyright (C) 2000-2001, Jeremy D. Zawodny.
Fix a bug. Add a feature. See your name here!
Many thanks go to these fine folks:
Suggested the idle/noidle stuff.
Mirnor bug report. Documentation fixes.
Long command-line options, Unix socket support.
Suggested batch mode.
Bug reports and usability suggestions.
Bug report about empty passwords not working.
Suggested -P command-line flag as well as other changes.
Suggested setting $0 to `mytop'.
Provided a fix for cases when we try remove the domain name from the display even if it is actually an IP address.
Provided the idea of real-time queries per second in the main display.
Pointed out some option-handling bugs.
Suggested that we don't mangle (normalize) whitespace in query info by default.
Make the --idle command-line argument negatable.
Noticed the inccorect formula for query cache hit percentages in version 1.2.
Supplied a patch to help filter binary junk in queries so that terminals don't freak out.
Supplied a patch that formed the basis for -prompt support. Sean Leach <email@example.com> submitted a similar patch.
Supplied a patch that formed the basis for -resolve support.
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 pgtop distribution page for more details on what has changed.
pgtop is licensed under the GNU General Public License version 2. For the full license information, please visit http://www.gnu.org/copyleft/gpl.html
4 POD Errors
The following errors were encountered while parsing the POD:
=cut found outside a pod block. Skipping to next block.
To install pgtop, copy and paste the appropriate command in to your terminal.
perl -MCPAN -e shell
For more information on module installation, please visit the detailed CPAN module installation guide.