PT-FINGERPRINT(1) User Contributed Perl Documentation PT-FINGERPRINT(1)NAMEpt-fingerprint - Convert queries into fingerprints.
SYNOPSIS
Usage: pt-fingerprint [OPTIONS] [FILES]
pt-fingerprint converts queries into fingerprints. With the --query
option, converts the option's value into a fingerprint. With no
options, treats command-line arguments as FILEs and reads and converts
semicolon-separated queries from the FILEs. When FILE is -, it read
standard input.
Convert a single query:
pt-fingerprint--query "select a, b, c from users where id = 500"
Convert a file full of queries:
pt-fingerprint /path/to/file.txt
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
DESCRIPTION
A query fingerprint is the abstracted form of a query, which makes it
possible to group similar queries together. Abstracting a query
removes literal values, normalizes whitespace, and so on. For example,
consider these two queries:
SELECT name, password FROM user WHERE id='12823';
select name, password from user
where id=5;
Both of those queries will fingerprint to
select name, password from user where id=?
Once the query's fingerprint is known, we can then talk about a query
as though it represents all similar queries.
Query fingerprinting accommodates a great many special cases, which
have proven necessary in the real world. For example, an IN list with
5 literals is really equivalent to one with 4 literals, so lists of
literals are collapsed to a single one. If you want to understand more
about how and why all of these cases are handled, please review the
test cases in the Subversion repository. If you find something that is
not fingerprinted properly, please submit a bug report with a
reproducible test case. Here is a list of transformations during
fingerprinting, which might not be exhaustive:
· Group all SELECT queries from mysqldump together, even if they are
against different tables. Ditto for all of pt-table-checksum's
checksum queries.
· Shorten multi-value INSERT statements to a single VALUES() list.
· Strip comments.
· Abstract the databases in USE statements, so all USE statements are
grouped together.
· Replace all literals, such as quoted strings. For efficiency, the
code that replaces literal numbers is somewhat non-selective, and
might replace some things as numbers when they really are not.
Hexadecimal literals are also replaced. NULL is treated as a
literal. Numbers embedded in identifiers are also replaced, so
tables named similarly will be fingerprinted to the same values
(e.g. users_2009 and users_2010 will fingerprint identically).
· Collapse all whitespace into a single space.
· Lowercase the entire query.
· Replace all literals inside of IN() and VALUES() lists with a
single placeholder, regardless of cardinality.
· Collapse multiple identical UNION queries into a single one.
OPTIONS
This tool accepts additional command-line arguments. Refer to the
"SYNOPSIS" and usage information for details.
--config
type: Array
Read this comma-separated list of config files; if specified, this
must be the first option on the command line.
--help
Show help and exit.
--match-embedded-numbers
Match numbers embedded in words and replace as single values. This
option causes the tool to be more careful about matching numbers so
that words with numbers, like "catch22" are matched and replaced as
a single "?" placeholder. Otherwise the default number matching
pattern will replace "catch22" as "catch?".
This is helpful if database or table names contain numbers.
--match-md5-checksums
Match MD5 checksums and replace as single values. This option
causes the tool to be more careful about matching numbers so that
MD5 checksums like "fbc5e685a5d3d45aa1d0347fdb7c4d35" are matched
and replaced as a single "?" placeholder. Otherwise, the default
number matching pattern will replace
"fbc5e685a5d3d45aa1d0347fdb7c4d35" as "fbc?".
--query
type: string
The query to convert into a fingerprint.
--version
Show version and exit.
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-fingerprint ... > 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-fingerprint>.
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.
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-fingerprint 2.2.14
perl v5.20.2 2015-04-10 PT-FINGERPRINT(1)
