Introduction In this article, we are going to see how a CROSS JOIN works, and we will also make use of this SQL join type to build a poker card game. Database table model For our poker card game application, we have created the ranks and suits database tables: The ranks table defines the ranking of cards, as well as the name and symbol used for each card rank: The suits table describes the four possible categories used by the French playing cards: Cartesian product In the set theory, the Cartesian product... Read More

The post A beginner’s guide to SQL CROSS JOIN appeared first on Vlad Mihalcea.

In my road trip of the Open Source projects using MySQL, after having tested WordPress, Drupal and Joomla, let’s try to install Magento using MySQL 8.0 !

In Magento’s manual, we can see that the project requires MySQL 5.6 and supports 5.7.x since versoin 2.1.2.

In my test, I will use Magento 2.3.3, the latest stable when writing this article.

The manual stipulates that we should use ROW based replication but not GTID because Magento 2 is using CREATE TEMPORARY TABLE inside transactions. …

To avoid infinite replication loops MySQL doesn’t allow you to have log_slave_updates and replicate-same-server-id.

When using GTIDs that may lead to something not expected that you may not be aware of.

In this scenario, we have 2 MySQL servers using GTID. The sever uuid part of the GTID has been modified in the illustration to make it more clear. Both servers have log_slave_updates enabled too:

So far nothing unusual. So let’s write data on the master (MySQL A):

We can see that this first …

In this part we are going to analyze a bit more complex query than before.
This query is a 6-way join.

The query is:
SELECT
        supp_nation,
        cust_nation,
        l_year,
        SUM(volume) AS revenue
FROM
        (
                SELECT
                        n1.n_name AS supp_nation,
                        n2.n_name AS cust_nation,
                        extract(year FROM l_shipdate) as l_year,
                        l_extendedprice * (1 - l_discount) AS …

Author: Robert Agar

The Internet of Things (IoT) has grown from an interesting concept to a paradigm that is changing the way individuals and businesses operate in the 21st Century. It is based on connecting IP-capable devices so they can communicate with each other in a variety of ways. They range from automated industrial assembly lines to smart appliances that promise to make life easier and more convenient for consumers.

A common aspect of all IoT implementations is that they make use of large amounts of data collected from network-connected devices. As with most data-centric applications, IoT systems rely on databases to store and process the accumulated information that drives them. MySQL is a valid choice in database platforms when you are designing a system that interacts with the IoT.

…

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If you want to back up your table and views, stored procedures, or stored function definitions, you can use mysqldump or mysqlpump to export the schema without the data. However, if you just want the views you need to look for another option. This blog shows how MySQL Shell comes to the rescue.

Backup the view definition using MySQL Shell

There are a couple of approaches to get the view definitions. One option is to consider the information_schema.VIEWS view which has the following columns:

mysql> SELECT COLUMN_NAME AS Field, COLUMN_TYPE AS Type
         FROM information_schema.COLUMNS
        WHERE TABLE_SCHEMA = 'information_schema'
              AND TABLE_NAME = 'VIEWS'
        ORDER BY ORDINAL_POSITION; …

In a MySQL 5.7 master-slave setup that uses the default semisynchronous replication setting for rpl_semi_sync_master_wait_point, a crash of the master and failover to the slave is considered to be lossless. However, when the crashed master comes back, you may find that it has transactions that are not present in the current master (which was previously a slave). This behavior may be puzzling, given that semisynchronous replication is supposed to be lossless, but this is actually an expected behavior in MySQL. Why exactly this happens is explained in full detail in the …

It has been possible to enable Transparent Data Encryption (TDE) in Percona Server for MySQL/MySQL for a while now, but have you ever wondered how it works under the hood and what kind of implications TDE can have on your server instance? In this blog posts series, we are going to have a look at how TDE works internally. First, we talk about keyrings, as they are required for any encryption to work. Then we explore in detail how encryption in Percona Server for MySQL/MySQL works and what the extra encryption features are that Percona Server for MySQL provides.

MySQL Keyrings

Keyrings are plugins that allow a server to fetch/create/delete keys in a local file (keyring_file) or on a remote server (for example, HashiCorp Vault). All keys are cached locally inside the keyring’s cache to speed up fetching keys. They can be separated into …

In this part we will discuss how NDB batch handling works. Query execution of
complex SQL queries means that more rows can be delivered than the receiver is
capable of receiving. This means that we need to create a data flow from the
producer where the data resides and the query executor in the MySQL Server.

The MySQL Server uses a record where the storage engine have to copy the result
row into the record. This means that the storage of batches of rows is taken
care of by the storage engine.

When NDB performs a range scan it will decide on the possible parallelism before
the scan is started. The NDB API have to allocate enough memory to ensure that
we have memory prepared to receive the rows as they arrive in a flow of result
rows from the data nodes. It is possible to set batch size of hundreds and even
thousands of rows for a query.

The …

We’re delighted to be able to share that Tungsten Clustering – our flagship product – is named in the DBTA 2020 List of Trend Setting Products!

Congratulations to all the products and their teams that were named in the 2020 list.

We have been at the forefront of the market need since 2004 with our solutions for platform agnostic, highly available, globally scaling, clustered MySQL databases that are driving businesses to the cloud (whether hybrid or not) today; and our software solutions are the expression of that.

Tungsten Clustering allows enterprises running business-critical MySQL database applications to cost-effectively …