I was recently asked this question by an experienced academic at the NY Oracle Users Group event I presented at.

Does MySQL support ACID? (ACID is a set of properties essential for a relational database to perform transactions, i.e. a discrete unit of work.)

Yes, MySQL fully supports ACID, that is Atomicity, Consistency, Isolation and Duration. (*)

This is contrary to the first Google response found searching this question which for reference states “The standard table handler for MySQL is not ACID compliant because it doesn’t support consistency, isolation, or durability”.

The question is however not a simple Yes/No because it depends on timing …

What is the difference between InnoDB locks and transaction isolation level? We’ll discuss it in this post.

Recently I received a question from a user about one of my earlier blog posts. Since it wasn’t sent as a comment, I will answer it here. The question:

> I am reading your article:
> https://www.percona.com/resources/technical-presentations/troubleshooting-locking-issues-percona-mysql-webinar

> Full table scan locks whole table.

> Some bad select (read) query can do full table scan on InnoDB, does it lock whole table please?

> My understanding was that SELECT (read) blocks another DML only in MyISAM.

To answer this question, we to need understand two different concepts: locking and …

In this blog post, we’ll discuss how to use multi-threaded LRU flushing to prevent bottlenecks in MySQL.

In the previous post, we saw that InnoDB 5.7 performs a lot of single-page LRU flushes, which in turn are serialized by the shared doublewrite buffer. Based on our 5.6 experience we have decided to attack the single-page flush issue first.

Let’s start with describing a single-page flush. If the working set of a database instance is bigger than the available buffer pool, existing data pages will have to be evicted or flushed (and then evicted) to make room for queries reading in new pages. InnoDB tries to anticipate this by maintaining a list of free pages per buffer pool instance; these are the pages that can be immediately used for placing the newly-read data pages. The target length of the free page list is governed by the …

InnoDB in MySQL 5.7 introduced for the first time the ability to create a general tablespace and assign multiple tables to it.  These tablespaces can be assigned anywhere on the system.  They can even be assigned a smaller block size so that they can contain compressed tables that use that size as their key_block_size.…

This blog discusses how TokuDB impacts InnoDB performance when the two run in the same environment.

You would think MySQL storage engines are fairly independent of each other, even in the same environment. Enabling one, or changing its configuration, logically should have no impact on the performance of other engines (such as InnoDB) when they are accessing tables. The reality, however, is more complicated than that!    

Now that we’ve shipped TokuDB, we’ve been getting feedback from our community and customers that enabling TokuDB might negatively affect performance – even for queries that don’t touch TokuDB tables (and in some cases, even when TokuDB is kept completely idle).

Percona is glad to announce the GA release of Percona Server 5.7.11-4 on March 15, 2016. Download the latest version from the Percona web site or from the Percona Software Repositories.

Based on MySQL 5.7.11, including all the bug fixes in it, Percona Server 5.7.11-4 is the current GA release in the Percona Server 5.7 series. All of Percona’s software is open-source and free, …

Percona is glad to announce the release of Percona Server 5.5.48-37.8 on March 4, 2016. Based on MySQL 5.5.48, including all the bug fixes in it, Percona Server 5.5.48-37.8 is now the current stable release in the 5.5 series.

Percona Server is open-source and free. Details of the release can be found in the 5.5.48-37.8 milestone on Launchpad. Downloads are available here and from the …

If you use a storage engine that supports transactions, you probably have faced or heard of deadlock's.

From MySQL Documentation:
“Always be prepared to re-issue a transaction if it fails due to deadlock. Deadlocks are not dangerous. Just try again.”

At work, we had an important job that sometimes were failing due to dead lock. I wanted to enhance it, so it will do what the documentation says ( Retry the transaction ). In order to do that, I wanted to have a scenario where I was able to reproduce the deadlock and the victim transaction was the one from the job I was fixing.

Create a deadlock is simple, you just need to have 2 sessions that each one holds a lock that the other is waiting for. For example:
We have a table that has 4 entries on it (entry 1, entry 2, entry 3, entry 4) and we have 2 …

Percona invites you to attend a webinar Wednesday, January 27th, with CEO Peter Zaitsev: Compression In Open Source Databases. Register now!

Data growth has been tremendous in the last decade and shows no signs of stopping. To deal with this trend database technologies have implemented a number of approaches, and data compression is by far the most common and important. Compression in open source databases is complicated, and there are a lot of different approaches – each with their own implications.

In this talk we will perform a survey of compression in some of the most popular open source database engines including: Innodb, TokuDB, MongoDB, WiredTiger, RocksDB, and PostgreSQL.

Important information: …

The Percona Live Data Performance Conference 2016 is rapidly approaching, and we’re looking forward to providing an outstanding experience April 18-21 for all whom attend.

Percona Live is the premier event for the rich and diverse open source community and businesses that thrive in the MySQL and NoSQL marketplaces. Attendees include DBAs, sysadmins, developers, architects, CTOs, and CEOs representing organizations from industry giants such as Oracle to start-ups. Vendors increasingly rely on the conference as a major opportunity to connect with potential high-value customers from around the world.

Below are some highlights for the upcoming conference regarding the conference schedule, Tutorial sessions, Birds of a Feather talks, and Lightning talks.

Conference Schedule

Percona Live is packed with engaging sessions, helpful …