When doing migrations or failovers in MySQL, there is usually a need to do a topology change and repoint replica servers to obtain replication data from a different server.

For example, given servers {A, B, and C} and the following topology:

If you need to repoint C to be a replica of B, i.e:

You can follow the next steps:

Note: log_replica_updates should be enabled on the soon-to-be primary as it is a prerequisite for chain replication.

Note: It is assumed that both replicas only stream from Server A and there are no conflicting replication filters in place that might break replication later on.

If Using File/Position-Based Replication:

1) Stop B and C

STOP REPLICA;

2) If replicas are multi-threaded, correct MTS gaps and make them …

Storing data is but one part of many in application development. Once data is stored, interested parties will likely want to see it. This is the Read aspect of CRUD – reading (or viewing) the data. Continue reading and see examples using CodeIgniter 4 built-in Model methods…

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If you enjoy the content written here, by all means, share this blog and your favorite post(s) with others who may benefit from or like it as well. Since coffee is my favorite drink, you can even buy me one if you would like!

In part 1 of this series, CodeIgniter 4 CRUD with MySQL: Create, I used the Model insert() method to store new rows of data. Now that the data is present in the table, we want to see that data.

There are 2 built-in Model …

MySQL, the world’s most popular open source database, is available as a managed cloud service in Oracle Cloud Infrastructure (OCI) under the name of MySQL Database Service (MDS).

This is the seventh episode of “Discovering MySQL Database Service“, a series of tutorials where I will show you, step by step, how to use MySQL Database Service and some other Oracle Cloud Infrastructure services.

In this episode, we’ll discover and use the OCI Bastion service to provide a restricted and time-limited access to administer our MySQL instance.

The post Discovering MySQL Database Service – Episode 7 – Use a Bastion SSH port forwarding session first appeared on dasini.net - Diary of a MySQL expert.

Here’s a second post focusing on the performance of MySQL on ZFS in cloud environments. In the first post, MySQL/ZFS Performance Update, we compared the performances of ZFS and ext4. This time we’ll look at the benefits of using ephemeral storage devices. These devices, called ephemeral in AWS, local in Google cloud, and temporary in Azure, are provided directly by the virtualization host. They are not network-attached and are not IO throttled, at least compared to regular storage. Not only can they handle a high number of IOPs, but their IO latency is also very low. For simplicity, we’ll name these devices local ephemeral. They can be quite large: Azure lsv2, Google Cloud n2, and AWS i3 instance types offer TBs of fast NVMe local ephemeral storage.

The main drawback of local ephemeral …

I’m studying and beginning to use CodeIgniter 4 in ‘real-world‘ projects and want to share what I learn, as I pick up on concepts of the framework. I’m posting a series of CRUD-related posts over on Medium and resharing them here for any readers who are interested…

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MySQL, the world’s most popular open source database, is available as a managed cloud service in Oracle Cloud Infrastructure (OCI) under the name of MySQL Database Service (MDS).

This is the sixth episode of “Discovering MySQL Database Service“, a series of tutorials where I will show you, step by step, how to use MySQL Database Service and some other Oracle Cloud Infrastructure services.

In this episode, we’ll introduce the concept of Security Lists a virtual firewall to control traffic at the network packet level.

The post Discovering MySQL Database Service – Episode 6 – Update the Private Subnet Security List first appeared on dasini.net - Diary of a MySQL expert.

We already saw how easy it’s to deploy solutions on OCI using Terraform and Resource Manager’s Stack. I’ve published several resources available on this page.

Today we will see how easy it’s to deploy Apache Superset on OCI using MySQL Data Service.

Apache Superset is an open source BI, Reporting, Charting tool that competes with Tableau, Looker, etc.  For a list of companies that have deployed Superset, see:  https://github.com/apache/superset/blob/master/RESOURCES/INTHEWILD.md.

Superset is loaded with options that make it easy for users of all skill sets to explore and visualize their data, from simple line charts to highly detailed geospatial charts.

For a gallery of …

Originally posted at Andres's blog. Traditional query optimizing is mostly about two things: first, in which order and from where to access data, and then how to then combine it. You have probably seen the tree shapes execution plans that are produced from query planning. I’ll use an example from the MySQL docs, using FORMAT=TREE which was introduced in MySQL 8.0: mysql>EXPLAINFORMAT=TREE->SELECT*->FROMt1->JOINt2->ON(t1.c1=t2.c1ANDt1.c2<t2.c2)->JOINt3->ON(t2.c1=t3.c1)\G***************************1.row***************************EXPLAIN:->Innerhashjoin(t3.c1=t1.c1)(cost=1.05rows=1)->Tablescanont3(cost=0.35rows=1)->Hash->Filter:(t1.c2<t2.c2)(cost=0.70rows=1)->Innerhashjoin(t2.c1=t1.c1)(cost=0.70rows=1)->Tablescanont2(cost=0.35rows=1)->Hash->Tablescanont1(cost=0.35rows=1)Here we can see that the MySQL optimizer thinks the best plan is to start reading from t1 using a table scan.

InnoDB background LRU list flushing is not limited by innodb_io_capcity or innodb_io_capacity_max. I’ll prove it in this blog post, but since MySQL experts disagree (or don’t know for sure), I’d like you to prove me wrong. This is not an intro; you’ll need to know all the InnoDB details wrt page flushing.

InnoDB background LRU list flushing is not limited by innodb_io_capcity or innodb_io_capacity_max. I’ll prove it in this blog post, but since MySQL experts disagree (or don’t know for sure), I’d like you to prove me wrong. This is not an intro; you’ll need to know all the InnoDB details wrt page flushing.