MySQL 8.0.24 has been released today \o/

As usual, it’s highly advised to read the release notes to get informed about the changes and bug fixed.

MySQL is Open Source and each release contains contributions from our great Community. Let me thanks all the contributors on behalf of the entire MySQL Team: Thank you !

MySQL 8.024 includes contributions from Daniël van Eeden, Kaiwang Chen, Zhai Weixiang, Venkatesh Prasad Venugopal, Jingbo Zhao, Yuxiang Jiang, Brian Yue, Hope Lee, Stanislav Revin, Mattias Jonsson, Facebook and a suggestion from Dmitriy Philimonov.

Once again, thank you all for your great contributions.

Here is the list of the above contributions and related bugs:

…

Introduction In this article, we are going to see what a Clustered Index is and why it’s very important to understand how tables are organized when using a relational database system. B+ Tree The most common index used in a relational database system is the B+ Tree one. Like the B-Tree index, the B+ Tree is a self-balanced ordered tree data structure. Both the B-Tree and the B-Tree start from a Root node and may have Internal Nodes and Leaf Nodes. However, unlike the B-Tree, the B+ Tree stores all the keys... Read More

The post Clustered Index appeared first on Vlad Mihalcea.

The MySQL Development team is very happy to announce that MySQL 8.0.24 is now available for download at dev.mysql.com. In addition to bug fixes there are a few new features added in this release.  Please download 8.0.24 from dev.mysql.com or from the MySQL  Yum,  APT, or SUSE repositories.…

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MySQL Group Replication is a plugin that helps to implement highly available fault-tolerant replication topologies. In this blog, I am going to explain the complete steps involved in the below two topics.

• How to convert the group replication member to an asynchronous replica
• How to convert the asynchronous replica to a group replication member

Why Am I Converting From GR Back to Old Async?

Recently I had a requirement from one of our customers running 5 node GR clusters. Once a month they are doing the bulk read job for generating the business reports. When they are doing the job, it affects the overall cluster performance because of the flow control issues. The node which is executing the read job is overloaded and delays the certification and writes apply process. The read job queries can’t be split across the cluster.  So, they don’t want that …

In this blog, we will discuss about how to perform cluster configuration changes while cluster is up and processing transactions (online).

In MySQL NDB Cluster, configuration data is parsed and distributed by the management server (MGMD) nodes. Users supply an input text file (commonly known as config.ini) which describes cluster topology, resource usage limits and other parameters. The MGMD nodes parse this file, combine it with designed in defaults and serve the resulting configuration to other node types (data nodes, api nodes), when they connect.
Reasons for changing configuration might include:

- Increased resource usage limits (Data memory, IndexMemory, buffers)
- Adding a new configuration parameter(s) i.e. enabling a new feature
- Unsupported configuration parameter taken out during downgrade to lower version i.e. disabling a feature
- etc ..

MySQL Cluster nodes pick …

In this blog series, I’m describing how InnoDB locks data (tables and rows) in order to provide illusion to clients that their queries are executed one after another, and how this was improved in recent releases.

So far we saw that access right currently granted and waiting to be granted are represented as record locks and table locks objects in memory, which we can inspect via performance_schema.data_locks.…

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Another common question I receive about MySQL Shell Dump & Load Utility is how to dump a schema and load it with another name. Make a copy in fact.

Dumping the Schema

To do so, we need to use the dumpTables() method:

JS  util.dumpTables("test", [], "/tmp/dump", {all: true})

It is important to notice that the second parameter is an empty array and the option “all” is enabled.

This will dump all tables of the test schena into /tmp/dump.

Loading the data into another Schema

Now, we will load the data we previously dump into another schema.

The first thing to do is to create the destination schema:

JS  \sql create database test2

And finally, we load the data:

JS  …

In this blog series, I’m describing how InnoDB locks data (tables and rows) in order to provide illusion to clients that their queries are executed one after another, and how this was improved in recent releases.

As we’ve already seen, the order in which server pretends transactions are happening (the serialization order) is tied to the order in which locks are granted to transactions.…

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While I was working on my grFailOver POC, I have also done some additional parallel testing. One of them was to see how online DDL is executed inside a Group Replication cluster.

The online DDL feature provides support for instant and in-place table alterations and concurrent DML. Checking the Group Replication (GR) official documentation, I was trying to identify if any limitation exists, but the only thing I have found was this:

“Concurrent DDL versus DML Operations.  Concurrent data definition statements and data manipulation statements executing against the same object but on different servers is not supported when using multi-primary mode. During execution of Data Definition Language (DDL) statements on an object, executing concurrent Data Manipulation Language (DML) on the …

As you know, the best way to perform logical dump for MySQL is to use MySQL Shell Dump & Load utilities. This is the most powerful option as it can dump and load in parallel (it also include many options to migrate to MDS very easily and supports OCI Object Store too).

One of the main question I receive related to MySQL Shell utility is related to the use of MySQL Shell in non-interactive mode with parameters requiring arrays.

What does that mean ?

For example if you want to dump a MySQL instance but you want to exclude some tables, you have an option called excludeSchemas and it expect an array of strings with the list of schemas you want to exclude in the dumb.

In interactive mode, this is how we use it:

JS> util.dumpInstance("/tmp/dump", {excludeSchemas: 
    ["mysql_innodb_cluster_metadata", "fred_test"], 
    threads: 8, showProgress: true})

However this notation is not …