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This Week in Data with Colin Charles 31: Meltdown/Spectre Performance Regressions and Percona Live 2018

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Have you been following the Meltdown/Spectre performance regressions? Some of the best blog posts have been coming from Brendan Gregg, who’s keynoting at Percona Live this year. We’ve also got Scott Simpson from Upwork giving a keynote about how and why they use MongoDB. This is in addition to all the other fun talks we have, so please register now. Don’t forget to also book your hotel room!

Even though the Percona Live conference now covers much more …

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MySQL : command delimiter curiosity – go & ego

Recently, I received a question related to GO as delimter to send a query. The user got some generated statements from a third party tool that looked like this:

/* CreateTable VersionInfo */

CREATE TABLE VersionInfo (Version BIGINT NOT NULL) ENGINE = INNODB

GO

/* VersionMigration migrated */

/* VersionUniqueMigration migrating ========================================== */

/* CreateIndex VersionInfo (Version) */

CREATE UNIQUE INDEX UC_Version ON VersionInfo (Version ASC)

GO

and so on…

To be honest I was lost ?! I never heard about that syntax and I was convinced that this was not valid (and you?)…

But in fact it is ! It’s the long command name for \g and EGO is the one for \G.

You can try help in the client (see the manual) and you will see it: …

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Sneak Peek at Proxytop Utility

In this blog post, I’ll be looking at a new tool Proxytop for managing MySQL topologies using ProxySQL. Proxytop is a self-contained, real-time monitoring tool for ProxySQL. As some of you already know ProxySQL is a popular open source, high performance and protocol-aware proxy server for MySQL and its forks (Percona and MariaDB).

My lab uses MySQL and ProxySQL on Docker containers provided by Nick Vyzas. This lab also uses Alexey Kopytov’s Sysbench utility to perform benchmarking against ProxySQL.

Pre-requisites:

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On RDBMS, NoSQL and NewSQL databases. Interview with John Ryan

“The single most important lesson I’ve learned is to keep it simple. I find designers sometimes deliver over-complex, generic solutions that could (in theory) do anything, but in reality are remarkably difficult to operate, and often misunderstood.”–John Ryan

I have interviewed John Ryan, Data Warehouse Solution Architect (Director) at UBS.

RVZ

Q1. You are an experienced Data Warehouse architect, designer and developer. What are the main lessons you have learned in your career?

John Ryan: The single most important lesson I’ve learned is to keep it simple. I find designers sometimes deliver over-complex, generic solutions that could (in theory) do anything, but in reality are remarkably difficult to operate, and often misunderstood. I believe this stems from a lack of understanding of the …

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MySQL 8.0 : more about new authentication plugin and replication

MySQL 8.0’s new default authentication plugin means more secure connections for users connections but also for replication… but you need to be aware of it !

Yesterday Giuseppe – the datacharmer – Maxia, submitted a bug related to a strange behavior of MySQL’s replication.

He observed that after creating a new user for replication (using the new authentication method, caching_sha2_password), when he created the slave as usual, replication was not starting… Slave_IO_Running was constantly in “Connecting” and the Last_IO_Error was:

Last_IO_Error: error connecting to master 'repl2@127.0.0.1:24011' - …
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Binlog Encryption with Percona Server for MySQL

In this blog post, we’ll look at how to turn on binlog encryption in Percona Server for MySQL.

Why do I need this?

As you probably know, Percona Server for MySQL’s binlog contains sensitive information. Replication uses the binlog to copy events between servers. They contain all the information from one server so that it can be applied on another. In other words, if somebody has access to a binlog, it means they have access to all the data in the server. Moreover, said person (or, “Hacker”) could create a clone copy of our server by just making a replica of it. In the end, they have access to our binlog. This shows how important protecting a binlog really is – leakage of binlogs not only make a particular table/tablespace or a group of tables accessible to a hacker, but literally the whole server …

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Migrating MySQL Users to Amazon RDS

In this blog post, we’ll look at what is needed when migrating MySQL users to Amazon RDS. We’ll discuss how we can transform MySQL user grants and make them compatible with Amazon RDS.

In order to deliver a managed service experience, Amazon RDS does not provide shell access to the underlying operating system. It also restricts access to certain procedures that require advanced privileges.

Every MySQL instance has some users with ALL PRIVILEGES, and you can’t directly migrate these users to Amazon RDS because it does not support following privileges for regular users.

  • SUPER – Enable use of other administrative operations such as CHANGE MASTER TO, KILL, PURGE BINARY …
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MySQL – Foreign keys and “Cannot delete or update a parent row: a foreign key constraint fails” error

As you know, foreign keys establish a sort of relationship between 2 tables. MySQL requires InnoDB storage engine to support foreign keys.

In our example, we have the following parent table in a MySQL 5.7.21 server:

mysqld3-(root@localhost) [sakila]> show create table actor\G
*************************** 1. row ***************************
       Table: actor
Create Table: CREATE TABLE `actor` (
  `actor_id` smallint(5) unsigned NOT NULL AUTO_INCREMENT,
  `first_name` varchar(45) NOT NULL,
  `last_name` varchar(45) NOT NULL,
  `last_update` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`actor_id`),
  KEY `idx_actor_last_name` (`last_name`)
) ENGINE=InnoDB AUTO_INCREMENT=201 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

 

and a foreign key is defined on the child table by using the “FOREIGN KEY… REFERENCES” syntax:

mysqld3-(root@localhost) [sakila]> show create …
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Comparison of Window Functions & CTEs in MySQL 8 vs MariaDB

Every MySQL database programmer should learn and apply the newly added MariaDB and MySQL Window Functions and Common Table Expressions(CTEs) in their daily work. Both CTEs and window functions enable easy solutions to many query challenges that in prior releases have been difficult and sometimes impossible to surmount. Mastering these features opens the door to query solutions that are more robust, execute faster, and are easier to maintain over time than prior solutions using older techniques.

In our last blog we compared User Roles in MySQL 8 vs. MariaDB.  Today, we will here compare Window Functions and Common Table Expressions in both databases.

Window Functions

While all database administrators are familiar with aggregate functions like COUNT(), SUM(), and AVG(), far less people make use of window functions in their queries.  Unlike aggregate functions, which operate on an entire table, window …

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Preparing your Community Connector for MySQL 8 – part 2 – SHA256

In part 1 of this series we looked at implementing support for the caching_sha2_password authentication plugin using the libmyqlclient C library.  This is possible for C based connectors or connectors that can make use of an external C library.  For some, this is not possible.  For example, Java and C# both function better if they don’t have to thunk out to an external library.  For these, implementing the MySQL client/server protocol natively is required.  This part 2 is about implementing support for the caching_sha2_password plugin natively.  It is expected that you already have a working connector and understand the client/server protocol.  For reference please internal documentation …

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