1MK-LOADAVG(1)         User Contributed Perl Documentation        MK-LOADAVG(1)
2
3
4

NAME

6       mk-loadavg - Watch MySQL load and take action when it gets too high.
7

SYNOPSIS

9       Usage: mk-loadavg [OPTION...] [DSN]
10
11       mk-loadavg watches the load on a MySQL server and takes action if it is
12       too high.
13
14       Execute my_script.sh when Threads_running exceeds 10:
15
16         mk-loadavg --watch "Status:status:Threads_running:>:10" \
17           --execute-command my_script.sh
18

RISKS

20       The following section is included to inform users about the potential
21       risks, whether known or unknown, of using this tool.  The two main
22       categories of risks are those created by the nature of the tool (e.g.
23       read-only tools vs. read-write tools) and those created by bugs.
24
25       mk-loadavg merely reads and prints information by default, and is very
26       low-risk.  The "--execute-command" option can execute user-specified
27       commands.
28
29       At the time of this release, we know of no bugs that could cause
30       serious harm to users.
31
32       The authoritative source for updated information is always the online
33       issue tracking system.  Issues that affect this tool will be marked as
34       such.  You can see a list of such issues at the following URL:
35       <http://www.maatkit.org/bugs/mk-loadavg>.
36
37       See also "BUGS" for more information on filing bugs and getting help.
38

DESCRIPTION

40       mk-loadavg watches a MySQL server and takes action when a defined
41       threshold is exceeded.  One or more items can be watched including
42       MySQL status values from SHOW STATUS, SHOW INNODB STATUS and SHOW SLAVE
43       STATUS, the three system load averages from "uptime", and values from
44       "vmstat".  Watched items and their threshold values are specified by
45       "--watch".  Every item is checked at intervals (see "--interval").  By
46       default, if any one item's check returns true (i.e. its threshold is
47       exceeded), then "--execute-command" is executed.  Specifying "--and"
48       requires that every item has exceeded its threshold before
49       "--execute-command" is executed.
50

OUTPUT

52       If you specify "--verbose", mk-loadavg prints information to STDOUT
53       about each check for each watched item.  Else, it prints nothing and
54       "--execute-command" (if specified) is responsible for logging any
55       information you want.
56

EXIT STATUS

58       An exit status of 0 (sometimes also called a return value or return
59       code) indicates success.  Any other value represents the exit status of
60       the Perl process itself, or of the last forked process that exited if
61       there were multiple servers to monitor.
62

OPTIONS

64       This tool accepts additional command-line arguments.  Refer to the
65       "SYNOPSIS" and usage information for details.
66
67       --and
68           group: Action
69
70           Trigger the actions only when all "--watch" items exceed their
71           thresholds.
72
73           The default is to trigger the actions when any one of the watched
74           items exceeds its threshold.  This option requires that all watched
75           items exceed their thresholds before any action is triggered.
76
77       --ask-pass
78           Prompt for a password when connecting to MySQL.
79
80       --charset
81           short form: -A; type: string
82
83           Default character set.  If the value is utf8, sets Perl's binmode
84           on STDOUT to utf8, passes the mysql_enable_utf8 option to
85           DBD::mysql, and runs SET NAMES UTF8 after connecting to MySQL.  Any
86           other value sets binmode on STDOUT without the utf8 layer, and runs
87           SET NAMES after connecting to MySQL.
88
89       --config
90           type: Array
91
92           Read this comma-separated list of config files; if specified, this
93           must be the first option on the command line.
94
95       --daemonize
96           Fork to the background and detach from the shell.  POSIX operating
97           systems only.
98
99       --database
100           short form: -D; type: string
101
102           Database to use.
103
104       --defaults-file
105           short form: -F; type: string
106
107           Only read mysql options from the given file.  You must give an
108           absolute pathname.
109
110       --execute-command
111           type: string; group: Action
112
113           Execute this command when watched items exceed their threshold
114           values
115
116           This command will be executed every time a "--watch" item (or all
117           items if "--and" is specified) exceeds its threshold.  For example,
118           if you specify "--watch "Server:vmstat:swpd:":0">, then this
119           command will be executed when the server begins to swap and it will
120           be executed again at each "--interval" so long as the server is
121           still swapping.
122
123           After the command is executed, mk-loadavg has no control over it,
124           so it is responsible for its own info gathering, logging, interval,
125           etc.  Since the command is spawned from mk-loadavg, its STDOUT,
126           STDERR and STDIN are closed so it doesn't interfere with mk-
127           loadavg.  Therefore, the command must redirect its output to files
128           or some other destination.  For example, if you specify
129           "--execute-command 'echo Hello'", you will not see "Hello" printed
130           anywhere (neither to screen nor "--log") because STDOUT is closed
131           for the command.
132
133           No information from mk-loadavg is passed to the command.
134
135           See also "--and".
136
137       --help
138           Show help and exit.
139
140       --host
141           short form: -h; type: string
142
143           Connect to host.
144
145       --interval
146           type: time; default: 60s; group: Watch
147
148           How long to sleep between each check.
149
150       --log
151           type: string
152
153           Print all output to this file when daemonized.
154
155           Output from "--execute-command" is not printed to this file.
156
157       --password
158           short form: -p; type: string
159
160           Password to use when connecting.
161
162       --pid
163           type: string
164
165           Create the given PID file when daemonized.  The file contains the
166           process ID of the daemonized instance.  The PID file is removed
167           when the daemonized instance exits.  The program checks for the
168           existence of the PID file when starting; if it exists and the
169           process with the matching PID exists, the program exits.
170
171       --port
172           short form: -P; type: int
173
174           Port number to use for connection.
175
176       --run-time
177           type: time
178
179           Time to run before exiting.
180
181           Causes "mk-loadavg" to stop after the specified time has elapsed.
182           Optional suffix: s=seconds, m=minutes, h=hours, d=days; if no
183           suffix, s is used.
184
185       --sentinel
186           type: string; default: /tmp/mk-loadavg-sentinel
187
188           Exit if this file exists.
189
190       --set-vars
191           type: string; default: wait_timeout=10000
192
193           Set these MySQL variables.  Immediately after connecting to MySQL,
194           this string will be appended to SET and executed.
195
196       --socket
197           short form: -S; type: string
198
199           Socket file to use for connection.
200
201       --stop
202           Stop running instances by creating the "--sentinel" file.
203
204       --user
205           short form: -u; type: string
206
207           User for login if not current user.
208
209       --verbose
210           short form: -v
211
212           Print information to STDOUT about what is being done.
213
214           This can be used as a heartbeat to see that mk-loadavg is still
215           properly watching all its values.  If "--log" is specified, this
216           information will be printed to that file instead.
217
218       --version
219           Show version and exit.
220
221       --vmstat
222           type: string; default: vmstat 1 2; group: Watch
223
224           vmstat command for "--watch" Server:vmstat:...
225
226           The vmstat output should look like:
227
228            procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
229            r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
230            0  0      0 590380 143756 571852    0    0     6     9  228  340  4  1 94  1
231            0  0      0 590400 143764 571852    0    0     0    28  751  818  4  2 90  3
232
233           The second line from the top needs to be column headers for
234           subsequent lines.  Values are taken from the last line.
235
236           The default, "vmstat 1 2",  gets current values.  Running just
237           "vmstat" would get average values since last reboot.
238
239       --wait
240           short form: -w; type: time; default: 60s
241
242           Wait this long to reconnect to MySQL.
243
244           If the MySQL server goes away between "--interval" checks, mk-
245           loadavg will attempt to reconnect to MySQL forever, sleeping this
246           amount of time in between attempts.
247
248       --watch
249           type: string; group: Watch
250
251           A comma-separated list of watched items and their thresholds
252           (required).
253
254           Each watched item is string of arguments separated by colons (like
255           arg:arg).  Each argument defines the watch item: what particular
256           value is watched and how to compare the current value to a
257           threshold value (N).  Multiple watched items can be given by
258           separating them with a comma, and the same watched item can be
259           given multiple times (but, of course, it only makes sense to do
260           this if the comparison and/or threshold values are different).
261
262           The first argument is the most important and is case-sensitive.  It
263           defines the module responsible for watching the value.  For
264           example,
265
266             --watch Status:...
267
268           causes the WatchStatus module to be loaded.  The second and
269           subsequent arguments are passed to the WatchStatus module which
270           parses them.  Each watch module requires different arguments.  The
271           watch modules included in mk-loadavg and what arguments they
272           require are listed below.
273
274           This is a common error when specifying "--watch" on the command
275           line:
276
277              mk-loadavg --watch Server:vmstat:swpd:>:0
278
279              Failed to load --watch WatchServer: Error parsing parameters vmstat:swpd:: No comparison parameter; expected >, < or = at ./mk-loadavg line 3100.
280
281           The "--watch" values need to be quoted:
282
283              mk-loadavg --watch "Server:vmstat:swpd:>:0"
284
285           Status
286               Watch SHOW STATUS, SHOW INNODB STATUS, and SHOW SLAVE STATUS
287               values.  The value argument is case-sensitive.
288
289                 --watch Status:[status|innodb|slave]:value:[><=]:N
290
291               Examples:
292
293                 --watch "Status:status:Threads_connected:>:16"
294                 --watch "Status:innodb:Innodb_buffer_pool_hit_rate:<:0.98"
295                 --watch "Status:slave:Seconds_behind_master:>:300"
296
297               You can easily see what values are available for SHOW STATUS
298               and SHOW SLAVE STATUS, but the values for SHOW INNODB STATUS
299               are not apparent.  Some common values are:
300
301                 Innodb_buffer_pool_hit_rate
302                 Innodb_buffer_pool_pages_created_sec
303                 Innodb_buffer_pool_pages_dirty
304                 Innodb_buffer_pool_pages_read_sec
305                 Innodb_buffer_pool_pages_written_sec
306                 Innodb_buffer_pool_pending_data_writes
307                 Innodb_buffer_pool_pending_dirty_writes
308                 Innodb_buffer_pool_pending_fsyncs
309                 Innodb_buffer_pool_pending_reads
310                 Innodb_buffer_pool_pending_single_writes
311                 Innodb_common_memory_allocated
312                 Innodb_data_fsyncs_sec
313                 Innodb_data_pending_fsyncs
314                 Innodb_data_pending_preads
315                 Innodb_data_pending_pwrites
316                 Innodb_data_reads_sec
317                 Innodb_data_writes_sec
318                 Innodb_insert_buffer_pending_reads
319                 Innodb_rows_read_sec
320                 Innodb_rows_updated_sec
321                 lock_wait_time
322                 mysql_tables_locked
323                 mysql_tables_used
324                 row_locks
325                 io_avg_wait
326                 io_wait
327                 max_io_wait
328
329               Several of those values can appear multiple times in the SHOW
330               INNODB STATUS output.  The value used for comparison is always
331               the highest value.  So the value for io_wait is the highest
332               io_wait value for all the IO threads.
333
334           Processlist
335               Watch aggregated SHOW PROCESSLIST values.
336
337                  --watch Processlist:[db|user|host|state|command]:value:[count|time]:[><=]:N
338
339               Examples:
340
341                 --watch "Processlist:state:Locked:count:>:5"
342                 --watch "Processlist:command:Query:time:<:1"
343
344           Server
345               Watch server values.
346
347                  --watch Server:loadavg:[1|5|15]:[><=]:N
348                  --watch Server:vmstat:[r|b|swpd|free|buff|cache|si|so|bi|bo|in|cs|us|sy|id|wa]:[><=]:N
349
350               Examples:
351
352                 --watch "Server:loadavg:5:>:4.00"
353                 --watch "Server:vmstat:swpd:>:0"
354                 --watch "Server:vmstat:free:=:0"
355
356               See "--vmstat".
357

DSN OPTIONS

359       These DSN options are used to create a DSN.  Each option is given like
360       "option=value".  The options are case-sensitive, so P and p are not the
361       same option.  There cannot be whitespace before or after the "=" and if
362       the value contains whitespace it must be quoted.  DSN options are
363       comma-separated.  See the maatkit manpage for full details.
364
365       •   A
366
367           dsn: charset; copy: yes
368
369           Default character set.
370
371       •   D
372
373           dsn: database; copy: yes
374
375           Default database.
376
377       •   F
378
379           dsn: mysql_read_default_file; copy: yes
380
381           Only read default options from the given file
382
383       •   h
384
385           dsn: host; copy: yes
386
387           Connect to host.
388
389       •   p
390
391           dsn: password; copy: yes
392
393           Password to use when connecting.
394
395       •   P
396
397           dsn: port; copy: yes
398
399           Port number to use for connection.
400
401       •   S
402
403           dsn: mysql_socket; copy: yes
404
405           Socket file to use for connection.
406
407       •   u
408
409           dsn: user; copy: yes
410
411           User for login if not current user.
412

DOWNLOADING

414       You can download Maatkit from Google Code at
415       <http://code.google.com/p/maatkit/>, or you can get any of the tools
416       easily with a command like the following:
417
418          wget http://www.maatkit.org/get/toolname
419          or
420          wget http://www.maatkit.org/trunk/toolname
421
422       Where "toolname" can be replaced with the name (or fragment of a name)
423       of any of the Maatkit tools.  Once downloaded, they're ready to run; no
424       installation is needed.  The first URL gets the latest released version
425       of the tool, and the second gets the latest trunk code from Subversion.
426

ENVIRONMENT

428       The environment variable "MKDEBUG" enables verbose debugging output in
429       all of the Maatkit tools:
430
431          MKDEBUG=1 mk-....
432

SYSTEM REQUIREMENTS

434       You need Perl, DBI, DBD::mysql, and some core packages that ought to be
435       installed in any reasonably new version of Perl.
436

BUGS

438       For a list of known bugs see <http://www.maatkit.org/bugs/mk-loadavg>.
439
440       Please use Google Code Issues and Groups to report bugs or request
441       support: <http://code.google.com/p/maatkit/>.  You can also join
442       #maatkit on Freenode to discuss Maatkit.
443
444       Please include the complete command-line used to reproduce the problem
445       you are seeing, the version of all MySQL servers involved, the complete
446       output of the tool when run with "--version", and if possible,
447       debugging output produced by running with the "MKDEBUG=1" environment
448       variable.
449

COPYRIGHT, LICENSE AND WARRANTY

451       This program is copyright 2008-2011 Baron Schwartz.  Feedback and
452       improvements are welcome.
453
454       THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
455       WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
456       MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
457
458       This program is free software; you can redistribute it and/or modify it
459       under the terms of the GNU General Public License as published by the
460       Free Software Foundation, version 2; OR the Perl Artistic License.  On
461       UNIX and similar systems, you can issue `man perlgpl' or `man
462       perlartistic' to read these licenses.
463
464       You should have received a copy of the GNU General Public License along
465       with this program; if not, write to the Free Software Foundation, Inc.,
466       59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
467

AUTHOR

469       Baron Schwartz, Daniel Nichter
470

ABOUT MAATKIT

472       This tool is part of Maatkit, a toolkit for power users of MySQL.
473       Maatkit was created by Baron Schwartz; Baron and Daniel Nichter are the
474       primary code contributors.  Both are employed by Percona.  Financial
475       support for Maatkit development is primarily provided by Percona and
476       its clients.
477

VERSION

479       This manual page documents Ver 0.9.7 Distrib 7540 $Revision: 7460 $.
480
481
482
483perl v5.34.0                      2021-07-22                     MK-LOADAVG(1)
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