The MySQL DROP statement is one of many powerful DDL commands. Be it ALTER TABLE some_table DROP some_column or DROP some_table, this type of command can drastically change your data landscape because in executing MySQL DROP, you are completely removing objects from the database! If you are using the phpMyAdmin web interface, you can execute the MySQL DROP statement with just a few mouse clicks. Continue reading to see how…

Drops of water.

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Note: The …

MySQL for RDS and DBaaS, in general, are very controlled environments by the vendors, meaning that there are missing things like a SUPER grant for the root user (and any user in general). This has some implications on operations, one of them being the impossibility of running pt-table-checksum to verify data consistency between a primary and its replicas.

However, there’s a workaround that might overcome this situation and involves three things:

• The pt-table-checksum itself
• A way to collect executed queries
• And the last one, which can be controversial, is to remove the read-only from the replica and use a maintenance window to stop traffic to the database while pt-table-checksum runs.

The problem with RDS is that you cannot change binlog_format to STATEMENT, which is one of the requirements for pt-table-checksum to run.

The workaround consists of capturing the executed …

ProxySQL is proud to announce the release of the latest stable version of ProxySQL 2.0.14 on the 8th of September 2020

ProxySQL is a high performance, high availability, protocol aware proxy for MySQL, with a GPL license! It can be downloaded here or alternatively from the ProxySQL Repository, and freely usable and accessible according to the GNU GPL v3.0 license.

Release Overview Highlights

Before discussing the features and fixes in this release we’d like to mention that we are aware of the delays in new releases. Ideally we would like to release ProxySQL more rapidly however we have recently been focusing our development efforts on ProxySQL 2.1.

The next edition of ProxySQL brings improved performance as well as many new and exciting …

You may have noticed, I started to blog also on the official Oracle MySQL Blog.

When I will do so, I will also publish my articles on lefred.be after a short delay.

I really invite you to follow the official Oracle MySQL Blog where you will find information related to MySQL Community but also about our webinars.

Currently, we put the highlight on our great new MySQL Database Service on OCI. My first post, is precisely dedicated to it.

In this blog series, I’d like to introduce you gently to the topic on which I was working last 2 years, which is improving how InnoDB locks data (tables and rows) in order to provide illusion to clients that their queries are executed one after another, while in reality there is a lot of concurrency.…

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After spending four years working with ProxySQL in production, I’ve learned a few interesting lessons about interpreting and processing query rules. I hope to save you some time (and avoid wrong turns) with this summary of ProxySQL query rules.

ProxySQL query engine is very powerful and supports the building of complex rule sets. These can be used to route traffic to backend MySQL instances, rewrite queries, and for traffic mirroring, among other use cases.

When the rule set is short and simple, you can easily understand what the outcome for a certain query would be. However, for complex sets or combined scenarios, you need a deeper understanding of the engine logic.

Note 1: Rules are processed in rule_id order

It might seem like a trivial start, but during testing or implementation, …

Over the last few months, I have written numerous blog posts on different features of the MySQL Shell ranging from basic CRUD to aggregate functions and DDL. As a part of the MySQL version 8 release, MySQL Shell is a powerful and alternative environment that you can manage and work with your data in using a choice of 3 languages: Python, Javascript, or SQL. So this blog post is a simple compilation of all the Python mode related posts, in one easy-to-access location…

Photo by Tamara Gore on Unsplash

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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 …

So you need to build a new set of databases, perhaps in a new location or geographical zone. Management wants it done yesterday cause the newly updated service hit the front page of reddit and your website and its back-end … Continue reading →

We sometimes receive challenging requests… this is a story about one of those times.

The customer has implemented a sharding solution and would like us to review alternatives or improvements. We analyzed the possibility of using ProxySQL as it looked to be a simple implementation. However, as we had 200 shards we had to implement 200 rules — the first shard didn’t have much overload, but the latest one had to go through 200 rules and took longer.

My first idea was to use FLAGIN and FLAGOUT creating a B-Tree, but the performance was the same. Reviewing the code, I realized that the rules were implemented as a list, which means that, in the end, all the rules were going to be processed until hit with the right one and FLAGIN is used just to filter out.

At that point, I asked, what could I do? Is it possible to implement it differently? What is the performance impact?

One Problem, Two Solutions

I …

ProxySQL brings a lot of value to your MySQL infrastructures such as Caching or Connection Multiplexing but it does not come free — your database needs to go through additional processing traffic which adds some overhead. In this blog post, we’re going to discuss where this overhead comes from and measure such overhead. 

Types of Overhead and Where it Comes From 

There are two main types of overhead to consider when it comes to ProxySQL — Network Overhead and Processing Overhead. 

Network Overhead largely depends on where you locate ProxySQL. For example, in case you deploy ProxySQL on the separate host (or hosts) as in this diagram: 

The application will have added network latency for all requests, compared to …