My post-FOSDEM detox has started - despite preparing by reading some survival guides, I hadn't really fathomed the variety and quantity (and quality) of beer that would flow over four days.  On reflection however, the beer flow has been far exceeded by the flow of tech content and conversation.

On Thursday and Friday I attended the pre-FOSDEM MySQL Days fringe event, where there were two tracks of talks and tutorials on MySQL including sessions on :
 - MySQL Server simplification
 - MySQL replication tooling improvements
 - Configuring group replication
 - Troubleshooting group replication
 - Using DNS for loadbalancing and failover
 - Upgrading to MySQL 8.0 …

In this tutorial, we'll learn to build an Angular CRUD example from scratch using the latest version which is as the time of this writing Angular 9.

We'll be using a CRUD REST API mocked using json-server which lets you generate a complete working API with nearly zero-lines of code.

We'll not be learning how to use json-server but you can see the complete instructions from this tutorial after generating the Angular project.

Step 1 — Mocking the Backend Using json-server Step 2 — Creating an Angular 9 Module Step 3 — Importing Angular HttpClientModule and FormsModule Step 4 — Creating Angular Component(s) Step 5 — Adding Angular Routing Step 6 — Creating an Angular Service Step 7 — Creating a Model Step 8 — Implementing the CRUD Methods Step 9 — Calling the CRUD Methods

Prerequisites

As always, we'll need to have a few prerequisites for this tutorial:

The basic concepts of …

It’s been a while since I wrote about ClickHouse, there are a lot of new features that are worth mentioning, and for this, I recommend to follow the Altinity Blog but today I want to look at the improved integration of ClickHouse and MySQL.

There are two features:

1. Using MySQL protocol and MySQL client to connect to ClickHouse
2. Use MySQL tables to select and join with ClickHouse tables

Using MySQL Protocol

By enabling MySQL protocol in ClickHouse server, you will allow for the MySQL command line tool or applications that typically connect to MySQL to connect to ClickHouse and execute queries.

With this, keep in mind:

• It does not automatically allow you to use MySQL SQL syntax, you still need to write queries in ClickHouse-dialect.
• The same issue with datatypes. ClickHouse uses Int32/Int64 …

Understanding how MySQL handles connections and Troubleshooting MySQL error 1040 – Too many connections! How to interpret “MySQL error 1040 – Too many connections ! ” ?

When a client tries to log into MySQL it may sometimes be rejected and receive an error message saying that there are “too many connections“. This means that the maximum number of clients that may be connected to the server has been reached. Either the client will have to wait for another client to log off, or the administrator will have to increase the maximum number of connections allowed.

Information about connections to a server can be found using the SHOW STATUS statement:

SHOW STATUS LIKE 'max_used_connections';

Prerequisite – Few points to remember before working or troubleshooting MySQL ” Too many connections ! ” error

1. MySQL does not have it’s own thread handling mechanism / …

Recently I had the discussion with one of my colleague about the impact of MySQL binary logs . It was a nice discussion and triggered me further to benchmark the MySQL with/without binary logs . The result is amazing

Server configuration :

• 4 CPU
• 8 GB RAM
• 100 GB SSD

MySQL version : 8.0.19

I have conducted the test with a bulk transaction . It is a single thread INSERT with 9.5 GB of data .

Test 1 – With binary log :

screen 1 :

from the screen 1, I had split my terminal to three screens .

1st screen : I have triggered the bulk INSERT

2nd screen : The INSERT has started to execute and in executing state .

3rd screen : You can see the individual table-space file ( .ibd ) keep growing ( 5.6 GB ) on …

I have been considering this for a while, but the 2019 edition of the MySQL Community Awards will be the final year. Over the past couple of years, the Percona Live conference has been expanding well beyond the walls of MySQL. There doesn’t seem to be an obvious event to hold the awards at, where there is both a large number of MySQL community members attending and the winners of the awards are also present.

The beauty of these awards was that there was no corporate entity involved – they were completely from the people and for the people. I was always really happy to give out an award to people that may not always be recognized and to celebrate what they had done.

The awards have been given out for 15 years now and they were picked up by the community from MySQL AB after 2009. I only managed the awards for a few years of the 15 total years, and before me — it was Shlomi Noach, and before him — Henrik Ingo. For a bunch of …

Codership is pleased to announce a new Generally Available (GA) release of Galera Cluster for MySQL 5.6 and 5.7, consisting of MySQL-wsrep 5.6.47 (release notes, download) and MySQL-wsrep 5.7.29 (release notes, download) with a new Galera Replication library 3.29 (release notes, download), implementing wsrep API version 25. This …

As hinted at earlier this month, we’re happy to announce our latest on-demand webinar:
“An Introduction to Database Proxies (for MySQL)”

In this webinar, Gilles Rayrat, our VP of Engineering and database proxies guru, shares some of his knowledge on the world of database proxies, how they work, why they’re important and what to use them for.

Starting with a simple database connectivity scenario, Gilles builds up the content by discussing clustered databases and what happens in the case of a failure through to explaining the important role database proxies play; including a more in-depth look into some advanced database connectivity setups and proxies functionalities.
…

Introduction In this article, we are going to see how the SQL EXISTS operator works and when you should use it. Although the EXISTS operator has been available since SQL:86, the very first edition of the SQL Standard, I found that there are still many application developers who don’t realize how powerful SQL subquery expressions really are when it comes to filtering a given table based on a condition evaluated on a different table. Database table model Let’s assume we have the following two tables in our database, that form a one-to-many... Read More

The post SQL EXISTS and NOT EXISTS appeared first on Vlad Mihalcea.

In my previous post (Puzzled by MySQL Replication), I describe a weird, but completely documented, behavior of replication that had me scratching my head for hours because it was causing data corruption.  I did not give too many details then as I also wanted allowing you to scratch your head if you wished.  In this post, I describe this behavior in more details.

But first I need to