Provided by: percona-toolkit_3.1+dfsg-1.1_all 
NAME
pt-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://jira.percona.com/projects/PT>. 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 2011-2018 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.
VERSION
pt-fingerprint 3.1.0