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

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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
…

This tutorial help to create advanced search functionality with PHP and Mysql. We’ll create a PHP form that takes input and search into the MySQL table. Advanced search provides more options to the end user to filter the search result. Steps to implement advanced search PHP mysqli Create a MySQL database and populate it with […]

The post Advanced search with PHP and MySQL appeared first on Phpflow.com.

OH:

“And now let’s quickly push 2 billion rows into this database VM.”

That is best done in YOLO mode. This is a mode of operation for a database that minimizes disk writes in favor of batched bulk writes.

It is not ACID, so if anything goes wrong during the load, the instance is lost. That is why it is called YOLO mode.

You are supposed to do this on a spare replica and not the production primary. If you are not having at least one more replica than needed in your MySQL deployment, I consider your setup defective.

Disable flush on Commit

set global innodb_flush_log_at_trx_commit = 2;

This config variable

gives up ACID commits: On COMMIT, …

Knowing your database can scale provides great peace of mind. We built PlanetScale on top of Vitess so that we could harness its ability to massively scale. One of the core strengths in our ability to scale is horizontal sharding. To demonstrate the power of horizontal sharding, we decided to run some benchmarking. We set up a PlanetScale database and started running some benchmarks with a common tpc-c sysbench workload. We weren’t aiming for a rigorous academic benchmark here, but we wanted to use a well-known and realistic workload. We will have more benchmark posts coming and have partnered with an academic institution who will be releasing their work soon. For this post, there are two goals. The first is to demonstrate PlanetScale’s ability to handle large query volumes. For this, we set a goal of a million queries per second. In Vitess terms, this is not a large cluster. There are many Vitess clusters running at much higher query volumes, …

Discover how PlanetScale handles one million queries per second (QPS) with horizontal sharding in MySQL

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 …

Window functions in MySQL offer developers an efficient way to view and compare data across a result set. In this post we will talk about some basic window function syntax and usage.

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 …