Oracle Virtualization and Cloud Consulting
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MySQL Feed

Oracle MySQL resources, news, and support articles.

Migrating Databases

mysql> DELETE FROM MySQL.employees WHERE name="Andrew";
Query OK, 1 row affected (0.06 sec)

> db.employees.insert({
name: {first: "Andrew",
last: "Morgan"},
startDate: new Date('June 25 2015'),
role: "Product Marketing"});

WriteResult({ "nInserted" : 1 })

Today was my last day working for MySQL/Oracle. I’ve really enjoyed my time here and it’s difficult to leave behind such great people and technology. Having said that, after 6.5 years it feels like the right time to move onto new challenges.

Percona XtraDB Cluster (PXC): How many nodes do you need?

A question I often hear when customers want to set up a production PXC cluster is: “How many nodes should we use?”Three nodes is the most common deployment, but when are more nodes needed? They also ask: “Do we always need to use an even number of nodes?”This is what we’ll clarify in this post.

Percona Monitoring Plugins 1.1.5 release

Percona is glad to announce the release of Percona Monitoring Plugins 1.1.5.Changelog:

Q&A: High availability when using MySQL in the cloud

Last week I hosted a webinar on using MySQL in the cloud for High Availability (HA) alongside 451 Research analyst Jason Stamper.

Getting EXPLAIN information from already running queries in MySQL 5.7

When a new version of MySQL is about to be released we read a lot of blog posts about the performance and scalability improvements. That’s good but sometimes we miss some small features that can help us a lot in our day-to-day tasks. One good example is the blog post that Aurimas wrote about a new small feature in MySQL 5.6 that I didn’t know about until I read it: the Automatic InnoDB transaction log file size change. How cool is that?

Update on the InnoDB double-write buffer and EXT4 transactions

In a post, written a few months ago, I found that using EXT4 transactions with the “data=journal” mount option, improves the write performance significantly, by 55%, without putting data at risk. Many people commented on the post mentioning they were not able to reproduce the results and thus, I decided to further investigate in order to find out why my results were different.

Speed up GROUP BY queries with subselects in MySQL

We usually try to avoid subselects because sometimes they force the use of a temporary table and limits the use of indexes. But, when is good to use a subselect?This example was tested over table a (1310723 rows), b, c and d ( 5 rows each) and with MySQL version 5.5 and 5.6.Let’s suppose we have a query like this:select a.name,sum(a.count) aSum,avg(a.position) aAVG,b.col1,c.col2,d.col3
from
a join
b on (a.bid = b.id) join
c on (a.cid = c.id) join
d on (a.did = d.id)
group by a.name,b.id,c.id,d.id

Percona XtraDB Cluster: Quorum and Availability of the cluster

Percona XtraDB Cluster (PXC) has become a popular option to provide high availability for MySQL servers. However many people are still having a hard time understanding what will happen to the cluster when one or several nodes leave the cluster (gracefully or ungracefully). This is what we will clarify in this post.Nodes leaving gracefullyLet’s assume we have a 3-node cluster and all nodes have an equal weight, which is the default.

Percona Live Europe 2015! Call for speakers; registration now open

Percona Live is moving from London to Amsterdam this year and the event is also expanding to three full days. Percona Live Europe 2015, September 21-23, will be at the Mövenpick Hotel Amsterdam City Centre.

Indexing MySQL JSON Data

“MySQL’s JSON data type is great! But how do you index the JSON data?” I was recently presenting at the CakePHP Cakefest Conference and was asked that very question. And I had to admit I had not been able to play, er, experiment with the JSON datatype to that level. Now I have and it is fairly easy.

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