Webinar slides: How To Upgrade to MySQL 5.7 - The Best Practices

Copyright 2016 Severalnines AB

How to upgrade to MySQL 5.7 - best practices

March 15, 2016

Krzysztof Książek

Severalnines

[email protected]

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mailto:[email protected]

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I'm Jean-Jérôme from the Severalnines Team and I'm your host for today's webinar!

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! Preparing an upgrade - changes between MySQL 5.6 and 5.7

! Information_schema

! SQL modes

! Authentication model

! Testing for upgrade

! Designing test environment

! Building test environment

! Executing tests

! Upgrade process

! Tools which may help you with upgrade process

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Agenda


Why upgrading to MySQL 5.7?

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! Better performance

! New features

! Multi source replication

! Intra-schema parallel replication

! Online buffer pool resize!!!

! Improved optimizer cost model

! Access to security and bugfix releases

! 5.5 ended its ‘Premier’ support, ‘Extended’ will end in 2018

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Why upgrading to MySQL 5.7?


Preparing an upgrade - reviewing changes

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! Information schema changes

! global_status, session_status, global_variables and session_variables moved to the performance_schema

! You can restore the original behavior by setting:SET GLOBAL show_compatibility_56=1

! This may affect different monitoring solutions

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! SQL mode changes

! STRICT_TRANS_TABLES mode is used by default

! No more inserting of invalid data like zeroed date or skipping column in INSERT when column doesn’t have explicit DEFAULT value

! This may cause issues if application relies on previous (definitely not so good) defaults

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! Authentication model changes

! Pre-4.1 passwords have been removed

! Password expiration has been added

! By default it’s not affecting 5.6 users ( >=5.7.11) but this default may change in the future (http://mysqlserverteam.com/an-update-on-default_password_lifetime)

! You should manually set the desired expiration policy for every user, after you upgraded to MySQL 5.7

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http://mysqlserverteam.com/an-update-on-default_password_lifetime


! Redo and undo log format changed - use innodb_fast_shutdown=0 when you stop 5.6 for upgrade

! YEAR(2) format has been removed

! User-defined locks system has changed - multiple locks are now possible

! ‘derived_merge’ optimizer switch may trigger SQL incompatibility

! For full list of changes look at: http://dev.mysql.com/doc/refman/5.7/en/upgrading-from-previous-series.html

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http://dev.mysql.com/doc/refman/5.7/en/upgrading-from-previous-series.html


Testing for upgrade

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Testing for upgrade

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! First step - design your test environment

! It should be as close to the production as possible

! Weaker hardware will lead to incorrect results

! Queries may be slower on weaker CPU and I/O subsystem

! or you will not catch a real regression - thinking it’s the hardware’s fault

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Testing for upgrade


! Dataset should be as close to the real data as possible

! Scrubbing dataset or cleaning confidential data may impact query execution plans - if you don’t have to, don’t clean your data

! You should be using real-world queries to test the performance

! Ideally, use your application for testing the logic and making sure all processes work as expected.

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Testing for upgrade


! Simplest way of building a test environment:

! create a slave from production master

! and then cut off replication

! Once we have 5.6 node with current dataset, we need to create another 5.6 node with a copy of this data

! Finally, we want to upgrade one of them to MySQL 5.7

! It’s nice as we can test the upgrade process while building test hosts

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Testing for upgrade


! We have hosts but we need to collect data for tests

! tcpdump or just slow query log would do

! both have some impact on the overall performance

! tcpdump can be executed outside of the database, to minimize the impact

! You want to collect all the queries - if you have some processes scheduled to run at a particular time, collect those queries too when they happen

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Testing for upgrade


! Once you have data, you can run some preliminary regression testing using pt-upgrade

! Run twice, first time using the ‘—save-results’ flag - it’ll save your time

! Generate report, investigate any reported issues

! pt-upgrade compares performance and result set

! Make sure you execute tests locally on the hosts, network latency may cause some impact

! Make sure both nodes are in the same state - cold or warmed up in exactly the same way

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Testing for upgrade


! pt-upgrade is not enough to cover all issues - yes, it’ll check performance and some obvious issues but you need to run more detailed tests

! If you have a set of acceptance tests you use to test new releases (you should have them), you can use those tests to check if upgrade affected core functions of your app

! Test application logic, make sure all operations work correctly, check all of the processes and APIs you may have in your app

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Testing for upgrade


! Once you have completed your tests, there's one more thing to check

! Rebuild your 5.7 node

! provision it again

! run mysql_upgrade, as you did earlier

! set it up as a slave

! Allow it to work as a slave for couple of days - it’ll confirm replication works fine between old and new versions

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Testing for upgrade


Upgrade process

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! Start with a single slave and upgrade it:

! Disable innodb_fast_shutdown

! Shut down MySQL

! Upgrade binaries to MySQL 5.7

! Start MySQL

! Run mysql_upgrade

! Restart MySQL

! Make sure replication is working and if needed, fix it

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Upgrade process


! Before upgrade - make sure you took the node out of rotation in a proxy layer or in your application

! After upgrade - if possible, put some limited traffic on the new host

! Observe how it behaves under real-world traffic

! CPU

! I/O

! Memory utilization

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Upgrade process


! Step by step increase the load to a normal level

! If everything is ok, proceed with upgrade on remaining slaves

! Once all of the slaves are upgraded, pick one of them as a new master

! Set it in a master-master replication with current, 5.6 master

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Upgrade process


! Perform a switchover to the new master

! If the old master keeps replicating, that’s great - upgrade it in a regular way

! If the old master replication breaks (i.e. incompatibilities in binlog format between old and new MySQL versions), rebuild it:

! Wipe the data

! Perform binary upgrade to MySQL 5.7

! Provision the data from slave and set up the replication

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Upgrade process


Tools which may help you with upgrade process

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! tcpdump

! tcpdump -s 65535 -x -nn -q -tttt -i any port 3306 > mysql.tcp.txt

! Helps you to collect queries exchanged between application hosts and database server

! Minimizes the impact caused by data collection (when executed outside of database node)

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! pt-upgrade, Percona Playback

! pt-upgrade is designed to check for performance and basic result set regressions

! Points you to queries which are not performing on the new version or they return different data

! Percona Playback is designed for load testing - replays slow log, trying to simulate real-world workload

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! MaxScale and ProxySQL

! Database-aware proxies help you through the upgrade process

! They route the traffic off the node when it goes down

! Help you with a warm-up period - use lower weight for new hosts to allow them to warm up properly

! ProxySQL can handle graceful switchover when used with external tool (for example, mysqlrpladmin, MHA or ClusterControl)

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! mysqlrpladmin, MHA

! Those tools can perform a switchover for you

! No need to make the changes in manual and error prone way - just run a script

! Those tools can be integrated with ProxySQL for graceful switchovers

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! ClusterControl

! Helps with provisioning of new nodes

! Perform a switchover for you

! Gives you clear insight into replication status

! Gives you clear insight into all database operations

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! More blogs covering different aspects of MySQL operations:

! http://severalnines.com/blog-categories/db-ops

! An ebook focused on upgrade process to MySQL 5.7 will become available soon

! Step-by-step guide through each part of the process

! Detailed explanations of different issues you may run into

! We’ll be at Percona Live in April, see you there!

! Contact: [email protected]

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Thank You!

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Webinar slides: How To Upgrade to MySQL 5.7 - The Best Practices

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