PT-FINGERPRINT(1p)					User Contributed Perl Documentation					PT-FINGERPRINT(1p)

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

       The following section is included to inform users about the potential risks, whether known or unknown, of using this tool.  The two main
       categories of risks are those created by the nature of the tool (e.g. read-only tools vs. read-write tools) and those created by bugs.

       The pt-fingerprint tool simply reads data and transforms it, so risks are minimal.

       See also "BUGS" for more information on filing bugs and getting help.

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:

       o   Group all SELECT queries from mysqldump together, even if they are against different tables.  Ditto for all of pt-table-checksum's
	   checksum queries.

       o   Shorten multi-value INSERT statements to a single VALUES() list.

       o   Strip comments.

       o   Abstract the databases in USE statements, so all USE statements are grouped together.

       o   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).

       o   Collapse all whitespace into a single space.

       o   Lowercase the entire query.

       o   Replace all literals inside of IN() and VALUES() lists with a single placeholder, regardless of cardinality.

       o   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 <http://www.percona.com/bugs/pt-fingerprint>.

       Please report bugs at https://bugs.launchpad.net/percona-toolkit <https://bugs.launchpad.net/percona-toolkit>.  Include the following
       information in your bug report:

       o   Complete command-line used to run the tool

       o   Tool "--version"

       o   MySQL version of all servers involved

       o   Output from the tool including STDERR

       o   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/ <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 developed by Percona for MySQL support and consulting.
       Percona Toolkit was forked from two projects in June, 2011: Maatkit and Aspersa.  Those projects were created by Baron Schwartz and
       developed primarily by him and Daniel Nichter, both of whom are employed by Percona.  Visit <http://www.percona.com/software/> for more
       software developed by Percona.

COPYRIGHT, LICENSE, AND WARRANTY
       This program is copyright 2011-2012 Percona Inc.  Feedback and improvements are welcome.

       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 2.1.2

perl v5.14.2							    2012-06-15							PT-FINGERPRINT(1p)