Recently, somebody asked me how he can find the long running transactions in MySQL.

I already have one MySQL Shell plugin that allows you to find the current transactions sorted by time. The plugin allows you to also get the details about the desired transaction. See check.getRunningStatements().

Let’s see how we can easily find those long transaction that can be a nightmare for the DBAs (see MySQL History List Length post).

SELECT thr.processlist_id AS mysql_thread_id,
       concat(PROCESSLIST_USER,'@',PROCESSLIST_HOST) User,
       Command,
       FORMAT_PICO_TIME(trx.timer_wait) AS trx_duration,
       current_statement as `latest_statement`
  FROM …

We often see an int column of a table that needs to be changed to unsigned-int and then unsigned-bigint due to the value being out of range. Sometimes, there may even be blockers that prevent us from directly altering the table or applying pt-online-schema-change on the primary, which requires the rotation solution: apply the change on the replica first, switch over the writes to the replica, and then apply the change on the previous primary. In this case, MySQL will have to replicate unsigned-int to unsigned-bigint for a while.

One might think it is obvious and straightforward that MySQL should be able to replicate unsigned-int to unsigned-bigint because unsigned-bigint has a larger size(8 bytes) which covers unsigned-int(4 bytes). It is partly true, but there are some tricks in practice. This blog will show you those tricks through the scenarios.

Let’s understand the scenarios and issues that one may face when replicating from …

Welcome to this week’s OpenLampTech newsletter, the newsletter for MySQL and PHP developers. There is always something to learn and share from all the curated sources out there and OpenLampTech has the MySQL, PHP, and LAMP Stack content covered. Thank you for reading!

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

In OpenLampTech issue #42 we have articles covering:

• Custom validation rules in Laravel
• MySQL time-saving Date functions
• PHP clean code tricks
• Web scraping with PHP
…

You may have read MyRocks Use Case: Big Dataset and been intrigued enough to want to evaluate RocksDB with InnoDB.  It has several advantages including requiring less storage space.

So how do you start?

On a fresh install of Percona Server for MySQL, install RocksDB by entering sudo apt install percona-server-rocksdb:

percona@DellXPS:~$ sudo apt install percona-server-rocksdb
[sudo] password for percona:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
percona-server-rocksdb
0 upgraded, 1 newly installed, 0 to remove and 32 not upgraded.
Need to get 65.3 MB of archives.
After this operation, 292 MB of additional disk space will be used.
Get:1 …

Since 8.0.30, you have the possibility to modify the InnoDB Redo Log Capacity online. An undersized Redo Log Capacity is problematic and lead to performance issues.

However, it’s not recommended to oversize the Redo Log either. Redo Log files consume disk space and increases the recovery time in case of a restart (innodb_fast_shutdown=1) or a sudden crash. And it also slows down shutdown when innodb_fast_shutdown=0.

This means that now, you don’t need to restart MySQL if you want to increase or decrease the size of the InnoDB Redo Logs files. In fact, we don’t talk anymore about file size but about capacity ! The DBA doesn’t need to specify any file size and/or amount of files for Redo Logs anymore …

My last blog, Percona Utilities That Make Major MySQL Version Upgrades Easier, detailed the tools available from the Percona toolkit that assists us with major MySQL version upgrades. The pt-upgrade tool aids in testing application queries and generates reports on how each question performs on servers running various versions of MySQL.

MySQL Shell Upgrade Checker is a utility that helps in compatibility tests between MySQL 5.7 instances and MySQL 8.0 upgrades, which is part of the mysql-shell-utilities. The util.checkForServerUpgrade() function checks whether the MySQL 5.7 instance is ready for the MySQL 8.0 upgrade and generates a report with warnings, errors, and notices for preparing the current MySQL 5.7 setup for upgrading to MySQL 8.0.

We can run this Upgrade Checker Utility in the current MySQL 5.7 …

We have another packed issue of OpenLampTech, the newsletter for MySQL and PHP developers, this week. I’m glad to have you here. Thank you!

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

In OpenLampTech issue #41, we are looking at articles covering:

• Is MySQL COUNT(*) slow?
• Symfony Twig UX components
• WordPress vs Drupal
• Top PHP testing tools
• And much much more…

Want Friday’s newsletter delivered to your inbox? Great!

Head over to the …

The MySQL Performance Schema is a gold mine of valuable data. Among the many nuggets you can extract from it is an historical report of transactions: how long a transaction took to execute, what queries were executed in it (with query metrics), and idle time between queries. Mining this information is not trivial, but it’s fun and this blog post shows how to start.

The MySQL Performance Schema is a gold mine of valuable data. Among the many nuggets you can extract from it is an historical report of transactions: how long a transaction took to execute, what queries were executed in it (with query metrics), and idle time between queries. Mining this information is not trivial, but it’s fun and this blog post shows how to start.

The MySQL Performance Schema is a gold mine of valuable data. Among the many nuggets you can extract from it is an historical report of transactions: how long a transaction took to execute, what queries were executed in it (with query metrics), and idle time between queries. Mining this information is not trivial, but it’s fun and this blog post shows how to start.