Showing entries 61 to 70 of 945
« 10 Newer Entries | 10 Older Entries »
Displaying posts with tag: innodb (reset)
Percona Server 5.7.13-6 is now available

Percona announces the GA release of Percona Server 5.7.13-6 on July 6, 2016. Download the latest version from the Percona web site or from the Percona Software Repositories.

Based on MySQL 5.7.13, including all the bug fixes in it, Percona Server 5.7.13-6 is the current GA release in the Percona Server 5.7 series. Percona’s provides completely open-source and free software. All the details of the release can be found in the …

[Read more]
Q: Does MySQL support ACID? A: Yes

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 …

[Read more]
InnoDB locks and transaction isolation level

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 …

[Read more]
Fun with Bugs #43 - Bugs Fixed in MySQL 5.7.13

For some reason I do not see numerous public announcements about recent MySQL 5.7.13 release, even though it happened a couple of days ago formally. Maybe that's because we do not have any really "big" new features in this release (new ->> operator for introduced though for those who, unlike me, care about JSON). Still there are many fixes for bugs previously reported by Community (or Oracle engineers, but still in public bugs database), and I'd like to discuss some of them.

Let me start with the bug that was NOT fixed though, Bug #81093, "mysqld_multi not included in mysql-community-server package", reported by Georgi Iovchev and …

[Read more]
Percona Server 5.7: multi-threaded LRU flushing

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 …

[Read more]
Fun with Bugs #42 - Bugs Fixed in MySQL 5.7.12

MySQL 5.7.12 was released more than 2 weeks ago. New features introduced there in a form of "rapid plugins" are widely discussed, but I am more interested in bugs reported by MySQL Community users that are fixed there. Unfortunately I do not see MySQL Community Release Notes by Morgan (like this) for quite a some time, so I have to continue describing key bug fixes and name people who reported and verified bugs in my "Fun with Bugs" series.

As usual, let's start with InnoDB bugs fixed:

  • Bug #80070 - "allocated_size and file_size differ if create general tablespace outside datadir". It was reported by my former colleague from Percona …
[Read more]
General Tablespaces in MySQL 5.7 – Details and Tips

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.…

TokuDB impacts InnoDB Performance?

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).

[Read more]
Percona Server 5.7.11-4 is now available

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, …

[Read more]
Percona Server 5.5.48-37.8 is now available


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 …

[Read more]
Showing entries 61 to 70 of 945
« 10 Newer Entries | 10 Older Entries »