PT-KILL(1) User Contributed Perl Documentation PT-KILL(1)NAMEpt-kill - Kill MySQL queries that match certain criteria.
SYNOPSIS
Usage: pt-kill [OPTIONS] [DSN]
pt-kill kills MySQL connections. pt-kill connects to MySQL and gets
queries from SHOW PROCESSLIST if no FILE is given. Else, it reads
queries from one or more FILE which contains the output of SHOW
PROCESSLIST. If FILE is -, pt-kill reads from STDIN.
Kill queries running longer than 60s:
pt-kill--busy-time 60 --kill
Print, do not kill, queries running longer than 60s:
pt-kill--busy-time 60 --print
Check for sleeping processes and kill them all every 10s:
pt-kill--match-command Sleep --kill --victims all --interval 10
Print all login processes:
pt-kill--match-state login --print --victims all
See which queries in the processlist right now would match:
mysql -e "SHOW PROCESSLIST" > proclist.txt
pt-kill--test-matching proclist.txt --busy-time 60 --print
RISKS
Percona Toolkit is mature, proven in the real world, and well tested,
but all database tools can pose a risk to the system and the database
server. Before using this tool, please:
· Read the tool's documentation
· Review the tool's known "BUGS"
· Test the tool on a non-production server
· Backup your production server and verify the backups
DESCRIPTIONpt-kill captures queries from SHOW PROCESSLIST, filters them, and then
either kills or prints them. This is also known as a "slow query
sniper" in some circles. The idea is to watch for queries that might
be consuming too many resources, and kill them.
For brevity, we talk about killing queries, but they may just be
printed (or some other future action) depending on what options are
given.
Normally pt-kill connects to MySQL to get queries from SHOW
PROCESSLIST. Alternatively, it can read SHOW PROCESSLIST output from
files. In this case, pt-kill does not connect to MySQL and "--kill"
has no effect. You should use "--print" instead when reading files.
The ability to read a file with "--test-matching" allows you to capture
SHOW PROCESSLIST and test it later with pt-kill to make sure that your
matches kill the proper queries. There are a lot of special rules to
follow, such as "don't kill replication threads," so be careful not to
kill something important!
Two important options to know are "--busy-time" and "--victims".
First, whereas most match/filter options match their corresponding
value from SHOW PROCESSLIST (e.g. "--match-command" matches a query's
Command value), the Time value is matched by "--busy-time". See also
"--interval".
Second, "--victims" controls which matching queries from each class are
killed. By default, the matching query with the highest Time value is
killed (the oldest query). See the next section, "GROUP, MATCH AND
KILL", for more details.
Usually you need to specify at least one "--match" option, else no
queries will match. Or, you can specify "--match-all" to match all
queries that aren't ignored by an "--ignore" option.
GROUP, MATCH AND KILL
Queries pass through several steps to determine which exactly will be
killed (or printed--whatever action is specified). Understanding these
steps will help you match precisely the queries you want.
The first step is grouping queries into classes. The "--group-by"
option controls grouping. By default, this option has no value so all
queries are grouped into one default class. All types of matching and
filtering (the next step) are applied per-class. Therefore, you may
need to group queries in order to match/filter some classes but not
others.
The second step is matching. Matching implies filtering since if a
query doesn't match some criteria, it is removed from its class.
Matching happens for each class. First, queries are filtered from
their class by the various "Query Matches" options like "--match-user".
Then, entire classes are filtered by the various "Class Matches"
options like "--query-count".
The third step is victim selection, that is, which matching queries in
each class to kill. This is controlled by the "--victims" option.
Although many queries in a class may match, you may only want to kill
the oldest query, or all queries, etc.
The forth and final step is to take some action on all matching queries
from all classes. The "Actions" options specify which actions will be
taken. At this step, there are no more classes, just a single list of
queries to kill, print, etc.
OUTPUT
If only "--kill" is given, then there is no output. If only "--print"
is given, then a timestamped KILL statement if printed for every query
that would have been killed, like:
# 2009-07-15T15:04:01 KILL 8 (Query 42 sec) SELECT * FROM huge_table
The line shows a timestamp, the query's Id (8), its Time (42 sec) and
its Info (usually the query SQL).
If both "--kill" and "--print" are given, then matching queries are
killed and a line for each like the one above is printed.
Any command executed by "--execute-command" is responsible for its own
output and logging. After being executed, pt-kill has no control or
interaction with the command.
OPTIONS
Specify at least one of "--kill", "--kill-query", "--print",
"--execute-command" or "--stop".
"--any-busy-time" and "--each-busy-time" are mutually exclusive.
"--kill" and "--kill-query" are mutually exclusive.
"--daemonize" and "--test-matching" are mutually exclusive.
This tool accepts additional command-line arguments. Refer to the
"SYNOPSIS" and usage information for details.
--ask-pass
Prompt for a password when connecting to MySQL.
--charset
short form: -A; type: string
Default character set. If the value is utf8, sets Perl's binmode
on STDOUT to utf8, passes the mysql_enable_utf8 option to
DBD::mysql, and runs SET NAMES UTF8 after connecting to MySQL. Any
other value sets binmode on STDOUT without the utf8 layer, and runs
SET NAMES after connecting to MySQL.
--config
type: Array
Read this comma-separated list of config files; if specified, this
must be the first option on the command line.
--create-log-table
Create the "--log-dsn" table if it does not exist.
This option causes the table specified by "--log-dsn" to be created
with the default structure shown in the documentation for that
option.
--daemonize
Fork to the background and detach from the shell. POSIX operating
systems only.
--database
short form: -D; type: string
The database to use for the connection.
--defaults-file
short form: -F; type: string
Only read mysql options from the given file. You must give an
absolute pathname.
--filter
type: string
Discard events for which this Perl code doesn't return true.
This option is a string of Perl code or a file containing Perl code
that gets compiled into a subroutine with one argument: $event.
This is a hashref. If the given value is a readable file, then pt-
kill reads the entire file and uses its contents as the code. The
file should not contain a shebang (#!/usr/bin/perl) line.
If the code returns true, the chain of callbacks continues;
otherwise it ends. The code is the last statement in the
subroutine other than "return $event". The subroutine template is:
sub { $event = shift; filter && return $event; }
Filters given on the command line are wrapped inside parentheses
like like "( filter )". For complex, multi-line filters, you must
put the code inside a file so it will not be wrapped inside
parentheses. Either way, the filter must produce syntactically
valid code given the template. For example, an if-else branch
given on the command line would not be valid:
--filter 'if () { } else { }' # WRONG
Since it's given on the command line, the if-else branch would be
wrapped inside parentheses which is not syntactically valid. So to
accomplish something more complex like this would require putting
the code in a file, for example filter.txt:
my $event_ok; if (...) { $event_ok=1; } else { $event_ok=0; } $event_ok
Then specify "--filter filter.txt" to read the code from
filter.txt.
If the filter code won't compile, pt-kill will die with an error.
If the filter code does compile, an error may still occur at
runtime if the code tries to do something wrong (like pattern match
an undefined value). pt-kill does not provide any safeguards so
code carefully!
It is permissible for the code to have side effects (to alter
$event).
--group-by
type: string
Apply matches to each class of queries grouped by this SHOW
PROCESSLIST column. In addition to the basic columns of SHOW
PROCESSLIST (user, host, command, state, etc.), queries can be
matched by "fingerprint" which abstracts the SQL query in the
"Info" column.
By default, queries are not grouped, so matches and actions apply
to all queries. Grouping allows matches and actions to apply to
classes of similar queries, if any queries in the class match.
For example, detecting cache stampedes (see "all-but-oldest" under
"--victims" for an explanation of that term) requires that queries
are grouped by the "arg" attribute. This creates classes of
identical queries (stripped of comments). So queries "SELECT c
FROM t WHERE id=1" and "SELECT c FROM t WHERE id=1" are grouped
into the same class, but query c<"SELECT c FROM t WHERE id=3"> is
not identical to the first two queries so it is grouped into
another class. Then when "--victims" "all-but-oldest" is specified,
all but the oldest query in each class is killed for each class of
queries that matches the match criteria.
--help
Show help and exit.
--host
short form: -h; type: string; default: localhost
Connect to host.
--interval
type: time
How often to check for queries to kill. If "--busy-time" is not
given, then the default interval is 30 seconds. Else the default
is half as often as "--busy-time". If both "--interval" and
"--busy-time" are given, then the explicit "--interval" value is
used.
See also "--run-time".
--log
type: string
Print all output to this file when daemonized.
--log-dsn
type: DSN
Store each query killed in this DSN.
The argument specifies a table to store all killed queries. The
DSN passed in must have the databse (D) and table (t) options. The
table must have at least the following columns. You can add more
columns for your own special purposes, but they won't be used by
pt-kill. The following CREATE TABLE definition is also used for
"--create-log-table". MAGIC_create_log_table:
CREATE TABLE kill_log (
kill_id int(10) unsigned NOT NULL AUTO_INCREMENT,
server_id bigint(4) NOT NULL DEFAULT '0',
timestamp DATETIME,
reason TEXT,
kill_error TEXT,
Id bigint(4) NOT NULL DEFAULT '0',
User varchar(16) NOT NULL DEFAULT '',
Host varchar(64) NOT NULL DEFAULT '',
db varchar(64) DEFAULT NULL,
Command varchar(16) NOT NULL DEFAULT '',
Time int(7) NOT NULL DEFAULT '0',
State varchar(64) DEFAULT NULL,
Info longtext,
Time_ms bigint(21) DEFAULT '0', # NOTE, TODO: currently not used
PRIMARY KEY (kill_id)
) DEFAULT CHARSET=utf8
--password
short form: -p; type: string
Password to use when connecting.
--pid
type: string
Create the given PID file. The tool won't start if the PID file
already exists and the PID it contains is different than the
current PID. However, if the PID file exists and the PID it
contains is no longer running, the tool will overwrite the PID file
with the current PID. The PID file is removed automatically when
the tool exits.
--port
short form: -P; type: int
Port number to use for connection.
--query-id
Prints an ID of the query that was just killed. This is equivalent
to the "ID" output of pt-query-digest. This allows cross-
referencing the output of both tools.
Example:
Query ID 0xE9800998ECF8427E
Note that this is a digest (or hash) of the query's "fingerprint",
so queries of the same form but with different values will have the
same ID. See pt-query-digest for more information.
--run-time
type: time
How long to run before exiting. By default pt-kill runs forever,
or until its process is killed or stopped by the creation of a
"--sentinel" file. If this option is specified, pt-kill runs for
the specified amount of time and sleeps "--interval" seconds
between each check of the PROCESSLIST.
--sentinel
type: string; default: /tmp/pt-kill-sentinel
Exit if this file exists.
The presence of the file specified by "--sentinel" will cause all
running instances of pt-kill to exit. You might find this handy to
stop cron jobs gracefully if necessary. See also "--stop".
--set-vars
type: Array
Set the MySQL variables in this comma-separated list of
"variable=value" pairs.
By default, the tool sets:
wait_timeout=10000
Variables specified on the command line override these defaults.
For example, specifying "--set-vars wait_timeout=500" overrides the
defaultvalue of 10000.
The tool prints a warning and continues if a variable cannot be
set.
--socket
short form: -S; type: string
Socket file to use for connection.
--stop
Stop running instances by creating the "--sentinel" file.
Causes pt-kill to create the sentinel file specified by
"--sentinel" and exit. This should have the effect of stopping all
running instances which are watching the same sentinel file.
--[no]strip-comments
default: yes
Remove SQL comments from queries in the Info column of the
PROCESSLIST.
--user
short form: -u; type: string
User for login if not current user.
--version
Show version and exit.
--[no]version-check
default: yes
Check for the latest version of Percona Toolkit, MySQL, and other
programs.
This is a standard "check for updates automatically" feature, with
two additional features. First, the tool checks the version of
other programs on the local system in addition to its own version.
For example, it checks the version of every MySQL server it
connects to, Perl, and the Perl module DBD::mysql. Second, it
checks for and warns about versions with known problems. For
example, MySQL 5.5.25 had a critical bug and was re-released as
5.5.25a.
Any updates or known problems are printed to STDOUT before the
tool's normal output. This feature should never interfere with the
normal operation of the tool.
For more information, visit
<https://www.percona.com/version-check>.
--victims
type: string; default: oldest
Which of the matching queries in each class will be killed. After
classes have been matched/filtered, this option specifies which of
the matching queries in each class will be killed (or printed,
etc.). The following values are possible:
oldest
Only kill the single oldest query. This is to prevent killing
queries that aren't really long-running, they're just long-
waiting. This sorts matching queries by Time and kills the one
with the highest Time value.
all Kill all queries in the class.
all-but-oldest
Kill all but the oldest query. This is the inverse of the
"oldest" value.
This value can be used to prevent "cache stampedes", the
condition where several identical queries are executed and
create a backlog while the first query attempts to finish.
Since all queries are identical, all but the first query are
killed so that it can complete and populate the cache.
--wait-after-kill
type: time
Wait after killing a query, before looking for more to kill. The
purpose of this is to give blocked queries a chance to execute, so
we don't kill a query that's blocking a bunch of others, and then
kill the others immediately afterwards.
--wait-before-kill
type: time
Wait before killing a query. The purpose of this is to give
"--execute-command" a chance to see the matching query and gather
other MySQL or system information before it's killed.
QUERY MATCHES
These options filter queries from their classes. If a query does not
match, it is removed from its class. The "--ignore" options take
precedence. The matches for command, db, host, etc. correspond to the
columns returned by SHOW PROCESSLIST: Command, db, Host, etc. All
pattern matches are case-sensitive by default, but they can be made
case-insensitive by specifying a regex pattern like "(?i-xsm:select)".
See also "GROUP, MATCH AND KILL".
--busy-time
type: time; group: Query Matches
Match queries that have been running for longer than this time.
The queries must be in Command=Query status. This matches a
query's Time value as reported by SHOW PROCESSLIST.
--idle-time
type: time; group: Query Matches
Match queries that have been idle/sleeping for longer than this
time. The queries must be in Command=Sleep status. This matches a
query's Time value as reported by SHOW PROCESSLIST.
--ignore-command
type: string; group: Query Matches
Ignore queries whose Command matches this Perl regex.
See "--match-command".
--ignore-db
type: string; group: Query Matches
Ignore queries whose db (database) matches this Perl regex.
See "--match-db".
--ignore-host
type: string; group: Query Matches
Ignore queries whose Host matches this Perl regex.
See "--match-host".
--ignore-info
type: string; group: Query Matches
Ignore queries whose Info (query) matches this Perl regex.
See "--match-info".
--[no]ignore-self
default: yes; group: Query Matches
Don't kill pt-kill's own connection.
--ignore-state
type: string; group: Query Matches; default: Locked
Ignore queries whose State matches this Perl regex. The default is
to keep threads from being killed if they are locked waiting for
another thread.
See "--match-state".
--ignore-user
type: string; group: Query Matches
Ignore queries whose user matches this Perl regex.
See "--match-user".
--match-all
group: Query Matches
Match all queries that are not ignored. If no ignore options are
specified, then every query matches (except replication threads,
unless "--replication-threads" is also specified). This option
allows you to specify negative matches, i.e. "match every query
except..." where the exceptions are defined by specifying various
"--ignore" options.
This option is not the same as "--victims" "all". This option
matches all queries within a class, whereas "--victims" "all"
specifies that all matching queries in a class (however they
matched) will be killed. Normally, however, the two are used
together because if, for example, you specify "--victims" "oldest",
then although all queries may match, only the oldest will be
killed.
--match-command
type: string; group: Query Matches
Match only queries whose Command matches this Perl regex.
Common Command values are:
Query
Sleep
Binlog Dump
Connect
Delayed insert
Execute
Fetch
Init DB
Kill
Prepare
Processlist
Quit
Reset stmt
Table Dump
See <http://dev.mysql.com/doc/refman/5.1/en/thread-commands.html>
for a full list and description of Command values.
--match-db
type: string; group: Query Matches
Match only queries whose db (database) matches this Perl regex.
--match-host
type: string; group: Query Matches
Match only queries whose Host matches this Perl regex.
The Host value often time includes the port like "host:port".
--match-info
type: string; group: Query Matches
Match only queries whose Info (query) matches this Perl regex.
The Info column of the processlist shows the query that is being
executed or NULL if no query is being executed.
--match-state
type: string; group: Query Matches
Match only queries whose State matches this Perl regex.
Common State values are:
Locked
login
copy to tmp table
Copying to tmp table
Copying to tmp table on disk
Creating tmp table
executing
Reading from net
Sending data
Sorting for order
Sorting result
Table lock
Updating
See
<http://dev.mysql.com/doc/refman/5.1/en/general-thread-states.html>
for a full list and description of State values.
--match-user
type: string; group: Query Matches
Match only queries whose User matches this Perl regex.
--replication-threads
group: Query Matches
Allow matching and killing replication threads.
By default, matches do not apply to replication threads; i.e.
replication threads are completely ignored. Specifying this option
allows matches to match (and potentially kill) replication threads
on masters and slaves.
--test-matching
type: array; group: Query Matches
Files with processlist snapshots to test matching options against.
Since the matching options can be complex, you can save snapshots
of processlist in files, then test matching options against queries
in those files.
This option disables "--run-time", "--interval", and
"--[no]ignore-self".
CLASS MATCHES
These matches apply to entire query classes. Classes are created by
specifying the "--group-by" option, else all queries are members of a
single, default class.
See also "GROUP, MATCH AND KILL".
--any-busy-time
type: time; group: Class Matches
Match query class if any query has been running for longer than
this time. "Longer than" means that if you specify 10, for
example, the class will only match if there's at least one query
that has been running for greater than 10 seconds.
See "--each-busy-time" for more details.
--each-busy-time
type: time; group: Class Matches
Match query class if each query has been running for longer than
this time. "Longer than" means that if you specify 10, for
example, the class will only match if each and every query has been
running for greater than 10 seconds.
See also "--any-busy-time" (to match a class if ANY query has been
running longer than the specified time) and "--busy-time".
--query-count
type: int; group: Class Matches
Match query class if it has at least this many queries. When
queries are grouped into classes by specifying "--group-by", this
option causes matches to apply only to classes with at least this
many queries. If "--group-by" is not specified then this option
causes matches to apply only if there are at least this many
queries in the entire SHOW PROCESSLIST.
--verbose
short form: -v
Print information to STDOUT about what is being done.
ACTIONS
These actions are taken for every matching query from all classes. The
actions are taken in this order: "--print", "--execute-command",
"--kill"/"--kill-query". This order allows "--execute-command" to see
the output of "--print" and the query before "--kill"/"--kill-query".
This may be helpful because pt-kill does not pass any information to
"--execute-command".
See also "GROUP, MATCH AND KILL".
--execute-command
type: string; group: Actions
Execute this command when a query matches.
After the command is executed, pt-kill has no control over it, so
the command is responsible for its own info gathering, logging,
interval, etc. The command is executed each time a query matches,
so be careful that the command behaves well when multiple instances
are ran. No information from pt-kill is passed to the command.
See also "--wait-before-kill".
--kill
group: Actions
Kill the connection for matching queries.
This option makes pt-kill kill the connections (a.k.a. processes,
threads) that have matching queries. Use "--kill-query" if you
only want to kill individual queries and not their connections.
Unless "--print" is also given, no other information is printed
that shows that pt-kill matched and killed a query.
See also "--wait-before-kill" and "--wait-after-kill".
--kill-query
group: Actions
Kill matching queries.
This option makes pt-kill kill matching queries. This requires
MySQL 5.0 or newer. Unlike "--kill" which kills the connection for
matching queries, this option only kills the query, not its
connection.
--print
group: Actions
Print a KILL statement for matching queries; does not actually kill
queries.
If you just want to see which queries match and would be killed
without actually killing them, specify "--print". To both kill and
print matching queries, specify both "--kill" and "--print".
DSN OPTIONS
These DSN options are used to create a DSN. Each option is given like
"option=value". The options are case-sensitive, so P and p are not the
same option. There cannot be whitespace before or after the "=" and if
the value contains whitespace it must be quoted. DSN options are
comma-separated. See the percona-toolkit manpage for full details.
· A
dsn: charset; copy: yes
Default character set.
· D
dsn: database; copy: yes
Default database.
· F
dsn: mysql_read_default_file; copy: yes
Only read default options from the given file
· h
dsn: host; copy: yes
Connect to host.
· p
dsn: password; copy: yes
Password to use when connecting.
· P
dsn: port; copy: yes
Port number to use for connection.
· S
dsn: mysql_socket; copy: yes
Socket file to use for connection.
· u
dsn: user; copy: yes
User for login if not current user.
· t
Table to log actions in, if passed through --log-dsn.
ENVIRONMENT
The environment variable "PTDEBUG" enables verbose debugging output to
STDERR. To enable debugging and capture all output to a file, run the
tool like:
PTDEBUG=1 pt-kill ... > FILE 2>&1
Be careful: debugging output is voluminous and can generate several
megabytes of output.
SYSTEM REQUIREMENTS
You need Perl, DBI, DBD::mysql, and some core packages that ought to be
installed in any reasonably new version of Perl.
BUGS
For a list of known bugs, see <http://www.percona.com/bugs/pt-kill>.
Please report bugs at <https://bugs.launchpad.net/percona-toolkit>.
Include the following information in your bug report:
· Complete command-line used to run the tool
· Tool "--version"
· MySQL version of all servers involved
· Output from the tool including STDERR
· Input files (log/dump/config files, etc.)
If possible, include debugging output by running the tool with
"PTDEBUG"; see "ENVIRONMENT".
DOWNLOADING
Visit <http://www.percona.com/software/percona-toolkit/> to download
the latest release of Percona Toolkit. Or, get the latest release from
the command line:
wget percona.com/get/percona-toolkit.tar.gz
wget percona.com/get/percona-toolkit.rpm
wget percona.com/get/percona-toolkit.deb
You can also get individual tools from the latest release:
wget percona.com/get/TOOL
Replace "TOOL" with the name of any tool.
AUTHORS
Baron Schwartz and Daniel Nichter
ABOUT PERCONA TOOLKIT
This tool is part of Percona Toolkit, a collection of advanced command-
line tools for MySQL developed by Percona. Percona Toolkit was forked
from two projects in June, 2011: Maatkit and Aspersa. Those projects
were created by Baron Schwartz and primarily developed by him and
Daniel Nichter. Visit <http://www.percona.com/software/> to learn
about other free, open-source software from Percona.
COPYRIGHT, LICENSE, AND WARRANTY
This program is copyright 2011-2015 Percona LLC and/or its affiliates,
2009-2011 Baron Schwartz.
THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, version 2; OR the Perl Artistic License. On
UNIX and similar systems, you can issue `man perlgpl' or `man
perlartistic' to read these licenses.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
VERSIONpt-kill 2.2.14
perl v5.20.2 2015-04-10 PT-KILL(1)
