Using CONNECT SE to access remote JSON data with demo examples in Docker

CONNECT is a storage engine (SE) plugin used to access external, local or remote data. In this blog we are going to show how to install the CONNECT storage engine in a Docker container and how to share JSON data between containers.

Enabling CONNECT SE plugin in Docker

CONNECT SE needs to be installed within the container in order to use it. To see how to do that please check Installing plugins in the MariaDB Docker Library Container.

Create JSON data on remote server

The most important feature of CONNECT SE to MariaDB is the flexibility to create tables from various data sources, like the same database and other DMBS’s tables or files with different formats.

Installing plugins in the MariaDB Docker Library Container

MariaDB plugins are software components that may be added to the core software without the need to rebuild the MariaDB Server. Plugins can be storage engines, additional security requirements, special log information about the server and others. MariaDB has a large number of built-in plugins which are permanently installed (listed in SHOW PLUGINS query). Plugins can be loaded at start-up, during initialization, or loaded dynamically when the server is running.

In this blog we are going to see how to list available plugins in the MariaDB container as well as the methods of installing plugins in a container.

10.7 feature preview: Miscellaneous features

The “Misc features” preview includes all the other features that did not make it into a separate dedicated preview binary.


MariaDB Server 10.7 includes the JSON_EQUALS function, which compares inputs as JSON objects, regardless of whitespace, key order, or number format.

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10.7 preview feature: Password Reuse Check plugin

By default, MariaDB does not check if a user reuses a password. Some security policies require users to choose a new password each time, and the Password Reuse Check plugin, available in a MariaDB 10.7.0 preview, enables this functionality.

Old passwords are stored in the mysql.password_reuse_check_history table, and the period they are retained for is determined by the password-reuse-check-interval system variable, which specifies a number of days. By default this is zero, meaning unlimited retention.

The password can be used in conjunction with other password validation plugins, such as the Simple Password Check plugin or the CrackLib Password Check plugin.

10.7 preview feature: CONVERT PARTITION

If you are using table partitioning, you have likely heard of the ALTER TABLE … EXCHANGE PARTITION … WITH TABLE … command. It existed in MariaDB since forever. But if you check the manual (any manual) or search the web, you will see that almost the only use case of it is converting a partition to a standalone non-partitoned table, or converting a standalone non-partitoned table into a partition.

And the usage was designed back then to be anything but obvious. To convert a partition to a table you need first to create an empty table with the same structure as a partition, then you exchange it with a partition, and then you drop the empty partition.

10.7 preview feature: Python-like string formatting

Sometimes there is a need to combine data from different columns into one string. For example,

SELECT CONCAT(first_name, ‘ ‘, last_name) FROM employees;

This doesn’t look too bad, but can quickly get out of hand, if you need to do something more complex than that. For example, let’s say, we also need to mention the salary here:

SELECT CONCAT(first_name, ‘ ‘, last_name, ‘ -‘, CAST(FORMAT(salary, 0) AS VARCHAR(10)), ‘ ‘, currency) FROM employees;

This preview shows a new feature for MariaDB 10.7 that was developed as a part of Google Summer of Code (MDEV-25015) by Alan Cueva, together with his mentor Vicențiu Ciorbaru.

10.7 preview feature JSON Histograms

MariaDB has had support for histograms as part of Engine Independent Table Statistics since 10.0. As part of Google Summer of Code (MDEV-21130), Michael Okoko, together with his mentor Sergey Petrunia, have implemented a new format (using JSON) for histograms that significantly improves the accuracy and flexibility of histograms. For those just interested in the feature details, you can skip to the “New format”, however if one is unfamiliar with the purpose of histograms, read on.

Why statistics are needed

Histograms are important for queries where the WHERE clause uses columns that are not indexed.

10.7.0 Comes As Preview Releases

Now is the time to try out the new candidate features of MariaDB Server 10.7, the next release series of MariaDB! This blog describes how the new preview releases work, and where we need your help as a MariaDB user.

The challenge: Making MariaDB mature quicker

Remember the challenges and visions I described two weeks ago? To address them we launch an experiment with several parallel preview releases of MariaDB Server 10.7 features.

This should solve two challenges mentioned in the blog: giving users early access to new functionality and making releases mature more rapidly through intensive internal testing.