NAME¶

pt-upgrade - Verify that query results are identical on different servers.

SYNOPSIS¶

Usage: pt-upgrade [OPTIONS] LOGS|RESULTS DSN [DSN]

pt-upgrade executes queries in the given MySQL "LOGS" on each "DSN", compares the results, and reports any significant differences. The tool can also save the results for later analyses. "LOGS" can be slow, general, binary, tcpdump, and "raw".

Compare host2 to host1 using queries in "slow.log":

   pt-upgrade h=host1 h=host2 slow.log

Compare host2 to saved results from host1:

   pt-upgrade h=host1 --save-results host1_results/ slow.log
   pt-upgrade host1_results1/ h=host2

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¶

pt-upgrade helps determine if it is safe to upgrade (or downgrade) to a new version of MySQL. A safe and conservative upgrade plan has several steps, one of which is ensuring that queries will produce identical results on the new version of MySQL.

pt-upgrade executes queries from slow, general, binary, tcpdump, and "raw" logs on two servers, compares many aspects of each query's exeuction and results, and reports any significant differences. The two servers are typically development servers, one running the current production version of MySQL and the other running the new version of MySQL.

USE CASES¶

pt-upgrade has two use cases. The first, canonical case is running "host to host". A log file and two DSN are given on the command line, one for each MySQL server. See the first example in the "SYNOPSIS". Queries are executed and compared on each server as the tool runs. Queries with differences are printed as the tool runs, or when it finishes (see "WHEN QUERIES ARE REPORTED"). Nothing is saved to disk, so this use case requires less hard disk space, but the queries must be executed on both servers if the tool is ran again, even if one of the servers hasn't changed. If there are a lot of queries or executing them takes a long time, and one server doesn't change, you may want to use the second use case.

The second use case is running "reference results to host". Reference results are the complete results from a single MySQL server, saved to disk. In this case, you must first generate the reference results with "--save-results", then run the tool a second time to compare another MySQL server to the results. See the second example in the "SYNOPSIS". Results are typically generated for the current version of MySQL which doesn't change. This use case can require a lot of disk space because the results (i.e. rows) for all queries must be saved, plus other data about the queries. If you plan to do many comparisons against a fixed version of MySQL, this use case is more efficient. Or if you don't have access to both servers at the same time, this use case allows you to "execute now, compare later".

IMPORTANT CONSIDERATIONS¶

QUERY DIFFERENCES¶

Significant query differences are determined by comparing these aspects of each query from both hosts:

Row count

The number of rows returned by the query should be the same. This is reported as "missing rows" under "Row diffs".

Row data

The row data returned by the query should be the same. All differences are significant: whitespace, float-precision, etc.

Warnings

The query should either not produce any errors or warnings, or produce the same errors or warnings.

Query time

A query rarely executes with a constant time, but its execution time should be within the same order of magnitude or smaller.

Query errors

If a query causes a SQL error on only one host, this is reported as "Query errors". Since the query works on one host, its syntax is probably valid, and the error is due to some condition unique to the other host.

SQL errors

If a query causes a SQL error on both hosts, this is reported as "SQL errors". The SQL syntax of the query could be invalid.

REPORT¶

As pt-upgrade runs, it prints queries with differences as soon as it can (see "WHEN QUERIES ARE REPORTED"). To prevent the report from becoming too long, queries are not reported individually but grouped by fingerprint into classes. A query fingerprint is the abstracted form of a query, created by removing literal values, normalizing whitespace, etc. So these queries belong to the same class:

   SELECT c FROM t WHERE id = 1
   SELECT c FROM t WHERE id=5
   select  c  from  t  where  id  =  9

The fingerprint for those queries is:

   select c from t where id=?

Each query class can have up to "--max-class-size" unique queries (1,000 by default). Up to "--max-examples" are reported for each type of difference, per query class. By virtue of being in the same class, an example of one query's difference is usually representative of all queries with the same difference, so it's not necessary to report every example. The total number of queries in a class with a particular difference is indicated in the report.

 #-----------------------------------------------------------------------
 # Logs
 #-----------------------------------------------------------------------
 File: /opt/mysql/slow.log
 Size: 59700
 #-----------------------------------------------------------------------
 # Hosts
 #-----------------------------------------------------------------------
 host1:
   DSN:       h=127.1,P=12345
   hostname:  dev1
   MySQL:     MySQL 5.1.68
 host2:
   DSN:       h=127.1,P=12348
   hostname:  dev2
   MySQL:     MySQL 5.5.10
 ########################################################################
 # Query class AAD020567F8398EE
 ########################################################################
 Reporting class because it has diffs, but hasn't been reported yet.
 Total queries      1
 Unique queries     1
 Discarded queries  0
 insert into t (id, username) values(?+)
 ##
 ## Warning diffs: 1
 ##
 -- 1.
    Code: 1265
   Level: Warning
 Message: Data truncated for column 'username' at row 1
 vs.
 No warning 1265
 INSERT INTO t (id, username) VALUES (NULL, 'long_username')
 #-----------------------------------------------------------------------
 # Stats
 #-----------------------------------------------------------------------
 failed_queries        0
 not_select            0
 queries_filtered      0
 queries_no_diffs      0
 queries_read          1
 queries_with_diffs    1
 queries_with_errors   0

WHEN QUERIES ARE REPORTED¶

A query class is reported as soon as any one of the "QUERY DIFFERENCES" or query errors has "--max-examples". Else, all queries with differences are reported when the tool finishes.

For example, if two query time differences are found for a query class, it is not reported yet. Once a third query time diffence is found, the query class is reported, including any other differences that may have been found too. Queries for the class will continue to be executed, but the class will not be reported again.

OUTPUT¶

The "REPORT" is printed to STDOUT as the tool runs. Internal warnings, errors, and "--progress" are printed to STDERR. To keep the two separate, run the tool like:

   pt-upgrade ... 1>report 2>err &

Then "tail -f err" while the tool is running to track its "--progress".

EXIT STATUS¶

In general, the tool exits zero if it finishes normally and there were no internal warnings or errors, and no "QUERY DIFFERENCES" were found. Else the tool exits non-zero with one or more of the following codes:

• 1

  There were too many internal errors or warnings; see STDERR. See also "--[no]continue-on-error".

• 4

  There were "QUERY DIFFERENCES"; see the "REPORT".

• 8

  "--run-time" expired; the tool did not finish reading the logs or reference results.

Other exit codes indicate that the tool crashed or died unexpectedly. The error that caused this should have printed to STDERR.

To check for a particular exit code, logical "AND" ("&") the final exit status with the exit code. For example, exit status 5 implies codes 1 and 4 because "5 & 1" is true, and "5 & 4" is true.

OPTIONS¶

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.

--[no]continue-on-error

default: yes

Continue parsing even if there is an error. The tool will not continue forever: it stops after 100 errors, in which case there is probably a bug in the tool or the input is invalid.

--[no]create-upgrade-table

default: yes

Create the "--upgrade-table" database and table.

--daemonize

Fork to the background and detach from the shell. POSIX operating systems only.

--database

short form: -D; type: string

Default database when connecting to MySQL.

--defaults-file

short form: -F; type: string

Only read MySQL options from the given file. You must give an absolute pathname.

--[no]disable-query-cache

default: yes

"SET SESSION query_cache_type = OFF" to disable the query cache.

--dry-run

Run but do not execute or compare queries. This is useful for checking command line options, connections to MySQL, and log or reference results parsing.

--filter

type: string

Allow events for which this Perl code returns true.

See the same option in the documentation for pt-query-digest.

--help

Show help and exit.

--host

short form: -h; type: string

MySQL hostname or IP.

--ignore-warnings

type: Hash

Ignore these MySQL warning codes when comparing warnings.

--log

type: string

Print STDOUT and STDERR to this file when daemonized. This option only takes affect when "--daemonize" is specified. The file is created if it doesn't exist, else output is appended to it.

--max-class-size

type: int; default: 1000

Max number of unique queries in each query class. See "REPORT".

--max-examples

type: int; default: 3

Max number of examples to list for each "QUERY DIFFERENCES". A query class is reported as soon as this many examples for any type of query difference are found.

--password

short form: -p; type: string

MySQL password for the "--user".

--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

MySQL port number.

--progress

type: array; default: time,30

Print progress reports to STDERR. The tool prints progress reports while reading logs or reference results, roughly estimating how long until it finishes.

The value is a comma-separated list with two parts. The first part can be percentage, time, or iterations; the second part specifies how often an update should be printed, in percentage, seconds, or number of iterations.

--[no]read-only

default: yes

Execute only "SELECT" and "SET" statements. If "--no-read-only" is specified, all queries are exeucted: "DROP", "DELETE", "UPDATE", etc. Even when running in default read-only mode, you should use a MySQL user with only "SELECT" privileges to insure against bugs in the tool.

--report

type: Hash; default: hosts, logs, queries, stats

Print these sections of the "REPORT".

--run-time

type: time

How long to run before exiting. By default, the tool runs until it finishes reading the logs or reference results.

--save-results

type: string

Save reference results to this directory. This option works only when one DSN is specified, to generate reference results. When comparing a host to reference results, specify its results directory instead of its DSN. See the second example in the "SYNOPSIS".

Reference results can use a lot of disk space.

--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.

--type

type: string; default: slowlog

Type of log files. Valid types are:

  VALUE    LOG TYPE
  =======  ===========================================
  slowlog  MySQL slow log
  genlog   MySQL general log
  binlog   MySQL binary log (converted by mysqlbinlog)
  tcpdump  TCP dump file generated by tcpdump command
  rawlog   Custom log with one SQL statement per line
    

--upgrade-table

type: string; default: percona_schema.pt_upgrade

Use this table to clear warnings. To clear all warnings from previous queries, pt-upgrade executes "SELECT * FROM --upgrade-table LIMIT 1" on each host before executing each query.

The table must be database-qualified. The database and table are automatically created unless "--no-create-upgrade-table" is specified (see "--[no]create-upgrade-table"). If the table does not already exist, it is created with this definition:

   CREATE TABLE pt_upgrade (
     id INT NOT NULL PRIMARY KEY
   )
    

--user

short form: -u; type: string

MySQL user if not the current system 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 its own version and also the versions of the following software: operating system, Percona Monitoring and Management (PMM), MySQL, Perl, MySQL driver for Perl (DBD::mysql), and Percona Toolkit. 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.

A secure connection to Percona’s Version Check database server is done to perform these checks. Each request is logged by the server, including software version numbers and unique ID of the checked system. The ID is generated by the Percona Toolkit installation script or when the Version Check database call is done for the first time.

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>.

--watch-server

type: string

Parse only events for this IP:port for "--type" tcpdump. All other IP addresses are ignored. If not specified, pt-upgrade watches all servers by looking for any IP address using port 3306 or "mysql". If you're watching a server with a non-standard port, this won't work, so you must specify the IP address and port to watch.

If you want to watch a mix of servers, some running on standard port 3306 and some running on non-standard ports, you need to create separate tcpdump outputs for the non-standard port servers and then specify this option for each. At present pt-upgrade cannot auto-detect servers on port 3306 and also be told to watch a server on a non-standard port.

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.

• L

  copy: yes

  Explicitly enable LOAD DATA LOCAL INFILE.

  For some reason, some vendors compile libmysql without the --enable-local-infile option, which disables the statement. This can lead to weird situations, like the server allowing LOCAL INFILE, but the client throwing exceptions if it's used.

  However, as long as the server allows LOAD DATA, clients can easily re-enable it; See <https://dev.mysql.com/doc/refman/5.0/en/load-data-local.html> and <http://search.cpan.org/~capttofu/DBD-mysql/lib/DBD/mysql.pm>. This option does exactly that.

  Although we've not found a case where turning this option leads to errors or differing behavior, to be on the safe side, this option is not on by default.

• p

  dsn: password; copy: yes

  Password to use when connecting. If password contains commas they must be escaped with a backslash: "exam\,ple"

• 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.

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-upgrade ... > 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-upgrade>.

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¶

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 2009-2018 Percona LLC and/or its affiliates. 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-upgrade 3.2.1

POD ERRORS¶

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