Planet MySQL Planet MySQL: Meta Deutsch Español Français Italiano 日本語 Русский Português 中文
10 Newer Entries Showing entries 31 to 40 of 190 10 Older Entries

Displaying posts with tag: MySQL 5.6 (reset)

MySQL 5.6 Certification Now GA!
Employee +3 Vote Up -0Vote Down

The MySQL 5.6 certification exams (Developer and DBA) are now GA!  A big thanks to all those who sat for the extended length beta exams – and subsequently waited for several months for your results.  Your feedback and the …

  [Read more...]
Many-table joins in MySQL 5.6
+3 Vote Up -0Vote Down

I recently worked on an uncommon slow query: less than 100 rows were read and returned, the whole dataset was fitting in memory but the query took several seconds to run. Long story short: the query was a join involving 21 tables, running on MySQL 5.1. But by default MySQL 5.1 is not good at handling joins with such a large number of tables. The good news is that MySQL 5.6 brings welcome improvements.

Isolating the problem

As always with a slow query, finding the execution plan with EXPLAIN is the 1st step to understand where time is spent. Here the plan was very good with almost all joins using the primary key or a unique …

  [Read more...]
Magic deadlock: what locks are really set by InnoDB?
+0 Vote Up -0Vote Down

Megabytes of text had been written already on InnoDB locking and deadlocks. Still, even very simple cases of deadlocks while working with a table having only one row sometimes make people wonder what happened and why.

Today I want to check if this topic is explained well in the manual and existing blog posts and understood properly. So, it's an exercise for my dear readers and those who like to report bugs as much as I do.

Let's consider a very simple example. In session #1 with default transaction isolation level execute the following:
CREATE TABLE `tt` (
  `id` int(11) NOT NULL,
  …






  [Read more...]
MySQL 5.6.16 Overview and Highlights
+6 Vote Up -0Vote Down

MySQL 5.6.16 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here:

http://dev.mysql.com/downloads/mysql/5.6.html

As opposed to the latest 5.5 release, this latest 5.6 release has quite a few more bug fixes, but that’s expected since 5.5 has been GA for much longer.

There were 2 minor functionality changes:

  • Previously, ALTER TABLE in MySQL 5.6 could alter a table such that the result had temporal columns in both 5.5 and 5.6 format. Now ALTER TABLE upgrades old temporal columns to 5.6 format for ADD COLUMN, CHANGE COLUMN, MODIFY COLUMN, …
  [Read more...]
MySQL 5.6.16 Community Release Notes
Employee +7 Vote Up -0Vote Down

Thank you to the MySQL Community, on behalf of the MySQL team @ Oracle. Your bug reports, testcases and patches have helped create a better MySQL 5.6.16.

In particular:

  • Thanks to Honza Horak for suggesting we make tmpdir configurable at build-time, and for providing a patch. Bug #68338.
  • Thanks to Hartmut Holzgraefe for reporting a memory leak when using the InnoDB memcached API and replication. …
  [Read more...]
Fun with Bugs #29 - important bug fixes in MySQL 5.6.16
+3 Vote Up -0Vote Down

As you should already know, Oracle had released MySQL 5.6.16 officially on January 31, 2014. You can find all the details in official release notes. In this post I decided to concentrate on important fixes for bugs reported by community in 4 most important categories: InnoDB, replication, partitioning and optimizer.

Let's start with Bug #70768, "Persistent optimizer statistics often causes LOCK_open stalls". It's well known that persistent statistics for InnoDB …

  [Read more...]
Percona Replication Manager (PRM) now supporting 5.6 GTID
+0 Vote Up -0Vote Down

Over the last few days, I integrated the MySQL 5.6 GTID version of the Percona Replication Manager (PRM) work of Frédéric Descamps, a colleague at Percona. The agent supports the GTID replication mode of MySQL 5.6 and if the master suffers a hard crash, it picks the slave having applied the highest transaction ID from the dead master. Given the nature of GTID-based replication, that causes all the other slaves to resync appropriately to their new master which is pretty cool and must yet be matched by the regular PRM agent.

For now, it is part of a separate agent, …

  [Read more...]
MySQL in Oracle Critical Patch Update Advisory January 2014
+0 Vote Up -0Vote Down

Oracle has released the Critical Patch Update (CPU) advisory for January 2014.

The affected MySQL products are:

  • Oracle MySQL Enterprise Monitor, versions 2.3, 3.0 
  • Oracle MySQL Server, versions 5.1, 5.5, 5.6

So this means that you should consider updating MySQL. For MySQL Enterprise the updates should be available on My Oracle Support and for the Community version the new versions are on the …




  [Read more...]
Multiple column index vs multiple indexes with MySQL 5.6
+4 Vote Up -0Vote Down

A question often comes when talking about indexing: should we use multiple column indexes or multiple indexes on single columns? Peter Zaitsev wrote about it back in 2008 and the conclusion then was that a multiple column index is most often the best solution. But with all the recent optimizer improvements, is there anything different with MySQL 5.6?

Setup

For this test, we will use these 2 tables (same structure as in Peter’s post):

CREATE TABLE t1000merge (
  id int not …
  [Read more...]
It can be a bright 2014
+1 Vote Up -0Vote Down


In many parts of the MySQL world, whether you have users, developers or administrators of MySQL, the season holidays are for family, relax, prayers, travel, or they are simply a moment where you can enjoy what you like or care most about.

For me, this time is dedicated to my family, but also to deeper thoughts around the strategies to adopt in short and long term. My work nowadays, as the work of many others, is ruled by quick decisions, by the "time to market” - whatever “market" means in a specific context. Decisions must be made in meetings that are time-boxed in one hour or even less. In the end, you accumulate so much work and high …


  [Read more...]
10 Newer Entries Showing entries 31 to 40 of 190 10 Older Entries

Planet MySQL © 1995, 2015, Oracle Corporation and/or its affiliates   Legal Policies | Your Privacy Rights | Terms of Use

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.