1MK-SLAVE-DELAY(1) User Contributed Perl Documentation MK-SLAVE-DELAY(1)
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6 mk-slave-delay - Make a MySQL slave server lag behind its master.
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9 To hold slavehost one minute behind its master for ten minutes:
10 mk-slave-delay --delay 1m --interval 15s --run-time 10m slavehost
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14 The following section is included to inform users about the potential
15 risks, whether known or unknown, of using this tool. The two main
16 categories of risks are those created by the nature of the tool (e.g.
17 read-only tools vs. read-write tools) and those created by bugs.
18 mk-slave-delay is generally very low-risk. It simply starts and stops
20 the replication SQL thread. This might cause monitoring systems to
21 think the slave is having trouble.
22 At the time of this release, mk-slave-delay does not reconnect to the
24 server if the connection is lost.
25 The authoritative source for updated information is always the online
27 issue tracking system. Issues that affect this tool will be marked as
28 such. You can see a list of such issues at the following URL:
29 http://www.maatkit.org/bugs/mk-slave-delay
30 <http://www.maatkit.org/bugs/mk-slave-delay>.
31 See also "BUGS" for more information on filing bugs and getting help.
33
35 "mk-slave-delay" watches a slave and starts and stops its replication
36 SQL thread as necessary to hold it at least as far behind the master as
37 you request. In practice, it will typically cause the slave to lag
38 between "--delay" and "--delay"+"--interval" behind the master.
39 It bases the delay on binlog positions in the slave's relay logs by
41 default, so there is no need to connect to the master. This works well
42 if the IO thread doesn't lag the master much, which is typical in most
43 replication setups; the IO thread lag is usually milliseconds on a fast
44 network. If your IO thread's lag is too large for your purposes,
45 "mk-slave-delay" can also connect to the master for information about
46 binlog positions.
47 If the slave's I/O thread reports that it is waiting for the SQL thread
49 to free some relay log space, "mk-slave-delay" will automatically
50 connect to the master to find binary log positions. If "--ask-pass"
51 and "--daemonize" are given, it is possible that this could cause it to
52 ask for a password while daemonized. In this case, it exits.
53 Therefore, if you think your slave might encounter this condition, you
54 should be sure to either specify "--use-master" explicitly when
55 daemonizing, or don't specify "--ask-pass".
56 The SLAVE-HOST and optional MASTER-HOST are both DSNs. See "DSN
58 OPTIONS". Missing MASTER-HOST values are filled in with values from
59 SLAVE-HOST, so you don't need to specify them in both places.
60 "mk-slave-delay" reads all normal MySQL option files, such as
61 ~/.my.cnf, so you may not need to specify username, password and other
62 common options at all.
63 "mk-slave-delay" tries to exit gracefully by trapping signals such as
65 Ctrl-C. You cannot bypass "--[no]continue" with a trappable signal.
66
68 mk-slave-delay requires the following privileges: PROCESS, REPLICATION
69 CLIENT, and SUPER.
70
72 If you specify "--quiet", there is no output. Otherwise, the normal
73 output is a status message consisting of a timestamp and information
74 about what "mk-slave-delay" is doing: starting the slave, stopping the
75 slave, or just observing.
76
78 --ask-pass
79 Prompt for a password when connecting to MySQL.
80 --charset
82 short form: -A; type: string
83 Default character set. If the value is utf8, sets Perl's binmode
85 on STDOUT to utf8, passes the mysql_enable_utf8 option to
86 DBD::mysql, and runs SET NAMES UTF8 after connecting to MySQL. Any
87 other value sets binmode on STDOUT without the utf8 layer, and runs
88 SET NAMES after connecting to MySQL.
89 --config
91 type: Array
92 Read this comma-separated list of config files; if specified, this
94 must be the first option on the command line.
95 --[no]continue
97 default: yes
98 Continue replication normally on exit. After exiting, restart the
100 slave's SQL thread with no UNTIL condition, so it will run as usual
101 and catch up to the master. This is enabled by default and works
102 even if you terminate "mk-slave-delay" with Control-C.
103 --daemonize
105 Fork to the background and detach from the shell. POSIX operating
106 systems only.
107 --defaults-file
109 short form: -F; type: string
110 Only read mysql options from the given file. You must give an
112 absolute pathname.
113 --delay
115 type: time; default: 1h
116 How far the slave should lag its master.
118 --help
120 Show help and exit.
121 --host
123 short form: -h; type: string
124 Connect to host.
126 --interval
128 type: time; default: 1m
129 How frequently "mk-slave-delay" should check whether the slave
131 needs to be started or stopped.
132 --log
134 type: string
135 Print all output to this file when daemonized.
137 --password
139 short form: -p; type: string
140 Password to use when connecting.
142 --pid
144 type: string
145 Create the given PID file when daemonized. The file contains the
147 process ID of the daemonized instance. The PID file is removed
148 when the daemonized instance exits. The program checks for the
149 existence of the PID file when starting; if it exists and the
150 process with the matching PID exists, the program exits.
151 --port
153 short form: -P; type: int
154 Port number to use for connection.
156 --quiet
158 short form: -q
159 Don't print informational messages about operation. See OUTPUT for
161 details.
162 --run-time
164 type: time
165 How long "mk-slave-delay" should run before exiting. The default
167 is to run forever.
168 --set-vars
170 type: string; default: wait_timeout=10000
171 Set these MySQL variables. Immediately after connecting to MySQL,
173 this string will be appended to SET and executed.
174 --socket
176 short form: -S; type: string
177 Socket file to use for connection.
179 --use-master
181 Get binlog positions from master, not slave. Don't trust the
182 binlog positions in the slave's relay log. Connect to the master
183 and get binlog positions instead. If you specify this option
184 without giving a MASTER-HOST on the command line, "mk-slave-delay"
185 examines the slave's SHOW SLAVE STATUS to determine the hostname
186 and port for connecting to the master.
187 "mk-slave-delay" uses only the MASTER_HOST and MASTER_PORT values
189 from SHOW SLAVE STATUS for the master connection. It does not use
190 the MASTER_USER value. If you want to specify a different username
191 for the master than the one you use to connect to the slave, you
192 should specify the MASTER-HOST option explicitly on the command
193 line.
194 --user
196 short form: -u; type: string
197 User for login if not current user.
199 --version
201 Show version and exit.
202
204 These DSN options are used to create a DSN. Each option is given like
205 "option=value". The options are case-sensitive, so P and p are not the
206 same option. There cannot be whitespace before or after the "=" and if
207 the value contains whitespace it must be quoted. DSN options are
208 comma-separated. See the maatkit manpage for full details.
209 · A
211 dsn: charset; copy: yes
213 Default character set.
215 · D
217 dsn: database; copy: yes
219 Default database.
221 · F
223 dsn: mysql_read_default_file; copy: yes
225 Only read default options from the given file
227 · h
229 dsn: host; copy: yes
231 Connect to host.
233 · p
235 dsn: password; copy: yes
237 Password to use when connecting.
239 · P
241 dsn: port; copy: yes
243 Port number to use for connection.
245 · S
247 dsn: mysql_socket; copy: yes
249 Socket file to use for connection.
251 · u
253 dsn: user; copy: yes
255 User for login if not current user.
257
259 You can download Maatkit from Google Code at
260 <http://code.google.com/p/maatkit/>, or you can get any of the tools
261 easily with a command like the following:
262 wget http://www.maatkit.org/get/toolname
264 or
265 wget http://www.maatkit.org/trunk/toolname
266 Where "toolname" can be replaced with the name (or fragment of a name)
268 of any of the Maatkit tools. Once downloaded, they're ready to run; no
269 installation is needed. The first URL gets the latest released version
270 of the tool, and the second gets the latest trunk code from Subversion.
271
273 The environment variable "MKDEBUG" enables verbose debugging output in
274 all of the Maatkit tools:
275 MKDEBUG=1 mk-....
277
279 You need Perl, DBI, DBD::mysql, and some core packages that ought to be
280 installed in any reasonably new version of Perl.
281
283 For list of known bugs see http://www.maatkit.org/bugs/mk-slave-delay
284 <http://www.maatkit.org/bugs/mk-slave-delay>.
285 Please use Google Code Issues and Groups to report bugs or request
287 support: <http://code.google.com/p/maatkit/>. You can also join
288 #maatkit on Freenode to discuss Maatkit.
289 Please include the complete command-line used to reproduce the problem
291 you are seeing, the version of all MySQL servers involved, the complete
292 output of the tool when run with "--version", and if possible,
293 debugging output produced by running with the "MKDEBUG=1" environment
294 variable.
295
297 This program is copyright 2007-2010 Sergey Zhuravlev and Baron
298 Schwartz. Feedback and improvements are welcome.
299 THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
301 WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
302 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
303 This program is free software; you can redistribute it and/or modify it
305 under the terms of the GNU General Public License as published by the
306 Free Software Foundation, version 2; OR the Perl Artistic License. On
307 UNIX and similar systems, you can issue `man perlgpl' or `man
308 perlartistic' to read these licenses.
309 You should have received a copy of the GNU General Public License along
311 with this program; if not, write to the Free Software Foundation, Inc.,
312 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
313
315 Sergey Zhuravlev, Baron Schwartz
316
318 This tool is part of Maatkit, a toolkit for power users of MySQL.
319 Maatkit was created by Baron Schwartz; Baron and Daniel Nichter are the
320 primary code contributors. Both are employed by Percona. Financial
321 support for Maatkit development is primarily provided by Percona and
322 its clients.
323
325 This manual page documents Ver 1.0.22 Distrib 6839 $Revision: 6835 $.
326perl v5.12.1 2010-08-01 MK-SLAVE-DELAY(1)