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Displaying posts with tag: MySQL (reset)
Percona Live Presents: An Open-Source, Cloud Native Database

During our presentation at Percona Live 2019 Intel and its software partners will introduce the audience to the work we’re doing to enable an open-source framework, we call Cloud Native Database. This is a collaborative effort between Intel, Rockset, PlanetScale, MariaDB and Percona.

Through the presentation the audience will be introduced to a set of principles and architectural elements that define what we mean by Cloud Native Database. We will discuss Rockset’s RocksDB-Cloud library and how it works with Facebook’s MyRocks storage engine. We also will cover …

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Exposing MyRocks Internals Via System Variables: Part 4, Compression and Bloom Filters

In this blog post, we continue on our series of exploring MyRocks mechanics by looking at the configurable server variables and column family options. In our last post, I explained at a high level how data moves from its initial disk-written files into the full data set structure of MyRocks using a process called compaction. In this post, we’re going to look a little closer at two important features that are leveraged as data cascades down through this compaction process: bloom filters and compression.

Bloom filters

Before we approach how bloom filters are used in MyRocks, we need to know what a bloom filter is. The short definition is that a bloom filter is a space-efficient data structure used to tell you if an element is present in a set. Make sense? No? No problem! When I read that I didn’t really understand what it was either, at least not to a useful extent. For a better and more complete description of what a bloom filter …

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CHECK constraints in MySQL

MySQL (really) supports CHECK CONSTRAINT since version 8.0.16. In this article I will show you 2 things: - An elegant way to simulate check constraint in MySQL 5.7 & 8.0. - How easy & convenient it is to use CHECK constraints in 8.0.16.

MySQL Tutorial – Managing MySQL Server Logs: Rotate, Compress, Retain & Delete

MySQL Server generates several logs that can help you monitor the activities of the server. However, once these logs are enabled, they can grow in size and start taking up too much disk space. This is why it’s important to have an automated way of archiving and preserving MySQL log files for a certain duration, as well as deleting the old ones. In this blog post, we describe some best practices for setting up and managing MySQL error logs, general logs and slow query logs for your MySQL deployments.

Setting Up MySQL Server Logging

Let’s look at how to setup the following 3 types of logs:

Error Log

Logs all the problems encountered during starting, running, or stopping mysqld. This log can be enabled by having the following option in /etc/my.cnf file:

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Solve Query Failures Regarding ONLY_FULL_GROUP_BY SQL Mode

“Hey, what’s going on with my applications? I installed a newer version of MySQL. I have queries that perfectly run with the older version and now I have a lot of errors.”

This is a question some customers have asked me after upgrading MySQL. In this article, we’ll see what one of the most frequent causes of this issue is, and how to solve it.

We are talking about this error:

ERROR 1055 (42000): Expression #2 of SELECT list is not in GROUP BY clause
and contains nonaggregated column 'test.web_log.user_id' which is not functionally
dependent on columns in GROUP BY clause; this is incompatible
with sql_mode=only_full_group_by

Have you ever seen it?


As the first thing let me introduce the concept of SQL_MODE.

MySQL can work using different SQL modes that affect the syntax of the queries and validation checks. Based on the configured value of the …

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Community Update for PL Open Source Database Conference 2019

It’s not long now before we’ll be gathering in Austin TX for this year’s Percona Live event. It’s the only conference of its type dedicated entirely to open source databases – of all marques. From a community perspective, we have a few updates to share.

Community Dinner

We’re happy to say that PlanetScale have stepped up to the plate (!) and are sponsoring this year’s community dinner alongside Percona. This year we are taking to the water and consequently numbers are limited to 100 attendees. If you are keen to join us, be sure to not miss the boat. 

The speakers’ perspective

For speakers who also enjoy writing, there’s an opportunity …

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Adding a little TLS complexity to authentication_ldap_simple

In a previous post I showed that by default when authentication_ldap_simple communicates with a Windows Domain Controller (or any other LDAP service), then the password is transmitted unencrypted during authentication.

This time I’ll demonstrate how to close this loophole.  A pre-requisite is that the Domain Controller needs to be configured to accept secure connections. This is done by installing a certificate, the process is well documented elsewhere so I won’t repeat it here.

There are two different ways to configure secure communication.  The first method is to set  …

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MySQL @OSD Poland on May 14

We would like to remind that you can find MySQL at OpenSource Day, Poland in Warsaw next Tuesday, May 14. Please find details below:

  • Name: OpenSource Day
  • Date: Tue, May 14, 2019
  • Place: Warsaw, Poland
  • MySQL Session: "MySQL InnoDB Cluster: High Availability with no stress!" given by Vittorio Cioe, the MySQL Senior Sales Consultant

This year we are sharing our resources with our friends from Oracle Linux team. You can find the Linux session just after MySQL one in the online agenda. We are also going to share the booth in expo area, so if you have any queries for either MySQL or Linux products, do not hesitate to come to talk to us to our booth in expo area! We are looking forward to talking to you in Warsaw!

CRUM conjecture - read, write, space and cache amplification

The RUM Conjecture asserts that an index structure can't be optimal for all of read, write and space. I will ignore whether optimal is about performance or efficiency (faster is better vs efficient-er is better). I want to use CRUM in place of RUM where C stands for database cache.

The C in CRUM is the amount of memory per key-value pair (or row) the DBMS needs so that either a point query or the first row from a range query can be retrieved with at most X storage reads. The C can also be reported as the minimal database : memory ratio to achieve at most X storage reads per point query.

My points here are:

  • There are …
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the MySQL Team in Austin, TX

At the end of the month, some engineers of the MySQL Team will be present in Austin, TX !

We will attend the first edition of Percona Live USA in Texas.

During that show, you will have the chance to meet key engineers, product managers, as well as Dave and myself.

Let me present you the Team that will be present during the conference:

The week will start with the MySQL InnoDB Cluster full day tutorial by Kenny and myself. This tutorial is a full hands-on tutorial where we will start by migrating a classical asynchronous master-replicas topology to a new MySQL InnoDB Cluster. We will then experience …

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