While EXPLAIN shows the selected query plan for a query, optimizer trace will show you WHY the particular plan was selected. From the trace you will be able to see what alternative plans was considered, the estimated costs of different plans, and what decisions was made during query optimization.

To turn on recording of optimizer trace for the current session:

SET optimizer_trace='enabled=on';

When optimizer trace is enabled, the information schema table optimizer_trace will contain the trace for the latest query that was explained or executed. I usually dump the trace to a file using this SQL statement:

SELECT trace FROM information_schema.optimizer_trace 
    INTO OUTFILE '<filename>' LINES TERMINATED BY '';

One important thing to note is that there is a configurable maximum size for the memory buffer used to record the trace. The default is …

If you want to use Form or Html class and when you will see error like HTML class not found OR Form class not found dont worry about that because Laravel 5 change the package you should download the HTML and FORM class helper from given instruction aboveAdd given bellow text to your compose

Wed, 2016-01-27 09:11maria-luisaraviol

One of the key issues in 2016 for DBAs to tackle will be Database Security, mainly associated to the increasing adoption of public and private clouds, as well as mission critical applications running on open source databases in large Enterprises.

Database security is one of the key topics for all the major vendors in the MySQL and MariaDB ecosystem. Oracle has just released version 5.7 of MySQL, with more features for standard authentication and proxy users, long awaited by the Community. Enterprise customers can also benefit of a PAM authentication plugin that can support LDAP. Percona has improved its PAM plugin and it is very much focused on features that are related to security, naming audit.

The recent release of the 10.1 version of MariaDB has given it a significant boost in security features, available, as usual, to the whole Community.

The efforts of the MariaDB team …

Back in October I have write about possible ways of running multiple MySQL instances on the same hardware. As the months passing by, the project of splitting our database schemas into standalone instances is closing in, so I started to check the different ways.

EDIT: This post is outdated, here is the follow up.

I started with docker, because we’ll use containers anyway with the applications, and I think it is a good idea to minimise the diversity of an infrastructure. I used the docker’s “official” Percona image (it is official by Docker not by Percona!) which is easy to use, and flexible enough. (https://hub.docker.com/_/percona/) This image supports using custom config files, you can mount your …

A modern MySQL server contains a lot of useful meta-data in information_schema and performance_schema, which can help bring visibility into what is happening inside of your database server. However, sometimes this data is quite fine grained and needs finessing in order to get to that point

MySQL 5.7 includes a new SYS schema installed by default.…

Back in October I have write about possible ways of running multiple MySQL instances on the same hardware. As the months passing by, the project of splitting our database schemas into standalone instances is closing in, so I started to check the different ways. EDIT: This post is outdated, here is the follow up. I started […]

I want to use LIKE query as work on sql i mean If using a SQL or Mysql Like query to query data it will return data even if its only partially matched if i search just t then it will return all the records match t so you can add LIKE statement by using querystringyou can easily implem

Tue, 2016-01-26 11:59maria-luisaraviol

In December 2015, MariaDB Evangelist Colin Charles was asked to present on MariaDB Security and Encryption at the London MySQL Meetup group. This blog is a summary of Colin’s presentation.

A few words about meetup groups

In December 2015, the London MySQL Meetup Group meeting took place at an amazing location: the Yoox Net-a-Porter Group offices at Westfield London Shopping Centre. A brilliant location and fantastic host: Yoox-Net-a-Porter not only sponsored the venue, but also offered great food and drinks (special thanks to them!).

The goal of the London MySQL Meetup Group is to keep up with the MySQL ecosystem awareness and it’s great to see rooms full of old and new faces every new meeting. Some of the group members work for the three major distribution companies, some are DBAs, some …

Last month/year I published a blog post on mysqlserverteam.com with an example of how MySQL 5.7 gives you improved performance for queries with derived tables.

The query example was part of my tutorial “How to Analyze and Tune MySQL Queries for Better Performance” at Oracle OpenWorld 2015. Slides for the entire presentation can be found here.

I want to use LIKE query as work on sql i mean If using a SQL or Mysql Like query to query data it will return data even if its only partially matched if i search just t then it will return all the records match t so you can add LIKE statement by using querystringyou can easily implem