NAME

SYNOPSIS

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

• 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

  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

--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

   PTDEBUG=1 pt-fingerprint ... > FILE 2>&1

Be careful: debugging output is voluminous and can generate several megabytes of output.

SYSTEM REQUIREMENTS

BUGS

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

   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

ABOUT PERCONA TOOLKIT

COPYRIGHT, LICENSE, AND WARRANTY

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