Provided by: percona-toolkit_3.2.1-1_all 
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
CONSISTENCY
Consistent environments and consistent data are crucial for obtaining an accurate report. pt-upgrade
should never be ran on a production server or any active server because there is no easy way to ensure a
synchronous read for each query. If data is changing on either server while pt-upgrade is running, the
report could contain more false-positives than legitimate differences. pt-upgrade assumes that both
MySQL servers are static, unchanging (except for any changes made by the tool if ran with
"--no-read-only"). A read-only workload shouldn't affect the tool, except maybe query times, so read-
only slaves could be used.
COMPARED TO
In a host to host comparison, results from the first host establish the norm to which results from the
second host are compared. In a reference results to host comparison, the reference results are the norm
to which the host is compared. Comparative phrases like "smaller than", "better than", etc. mean
compared to the norm.
For example, if the query time for an event is 0.01 on the first host and 0.5 on the second host, that is
a significant difference because 0.5 is worse than 0.1, and so the query will be reported.
READ-ONLY
By default, pt-upgrade only executes "SELECT" and "SET" statements. (This does not include
'SELECT...INTO' statements, which do not return rows but dump output to a file or variable.) If you're
using recreatable test or development servers and wish to compare write statements too (e.g. "INSERT",
"UPDATE", "DELETE"), then specify "--no-read-only". If using a binary log, you must specify
"--no-read-only" because binary logs don't contain "SELECT" statements. See "--[no]read-only".
TRANSACTIONS
The tool does not create its own transactions, but any transactions in the "LOG" are executed as-is.
Since logs are serial, transactions shouldn't normally be an issue. If, however, you need to compare
queries that are somehow transactionally related (in which case you probably also need to disable
"--[no]read-only"), then pt-upgrade probably won't do what you need because it's not designed for this
purpose.
pt-upgrade runs with "autocommit=1" by default.
THROTTLING
pt-upgrade has no throttling options because the tool should only be ran on dedicated testing or
development servers. Do not run pt-upgrade on production servers! Consequently, the tool is CPU,
memory, disk, and network intensive. It executes queries as fast as possible.
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.
EXAMPLE
#-----------------------------------------------------------------------
# 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
The "Query class <ID>" sections are the most important because they list "QUERY DIFFERENCES". The first
part of the section lists the reason why the query class was report, followed by counts of queries in the
class, followed by the fingerprint which defines the class.
The rest of the query class section lists the "QUERY DIFFERENCES" that caused the class to be reported.
Each type of difference begins with a double hash mark header that lists the type and total number of
queries in the class with the difference. Then up to "--max-examples" are listed, numbered "-- 1.", "---
2.", etc. Each example lists the difference for the first and second hosts (respective to the "Hosts"
section), followed by the first SQL statement that revealed the difference.
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
Hey! The above document had some coding errors, which are explained below:
Around line 11245:
Non-ASCII character seen before =encoding in 'Percona’s'. Assuming UTF-8
perl v5.30.3 2020-08-30 PT-UPGRADE(1p)