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Displaying posts with tag: MySQL (reset)
Smart Update Strategy in Percona Kubernetes Operator for Percona XtraDB Cluster

In Percona Kubernetes Operator for Percona XtraDB Cluster (PXC) versions prior to 1.5.0, there were two methods for upgrading PXC clusters, and both of these use built-in StatefulSet update strategies. The first one is manual (OnDelete update strategy) and the second one is semi-automatic (RollingUpdate strategy). Since the Kubernetes operator is about automating the database management, and there are use cases to always keep the database up to date, a new smart update strategy was implemented.

Smart Update Strategy

The smart update strategy can be used to enable automatic context-aware upgrades of PXC clusters between minor versions. One of the use cases for automatic upgrades is if you want to get security …

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MySQL Shell and storing passwords

If you plan for example to have a bastion host in the cloud to access all your MySQL servers and use only MySQL Shell, the first time you connect to one of the host, you will realize that MySQL Shell prompts for a password but doesn’t ask you to store it of not.

Example:

mysqlsh fred@192.168.5.94
Please provide the password for 'fred@192.168.5.94': ****
MySQL Shell 8.0.21
Copyright (c) 2016, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its affiliates.
Other names may be trademarks of their respective owners.
Type '\help' or '\?' for help; '\quit' to exit.
Creating a session to 'fred@192.168.5.94'
Fetching schema names for autocompletion… Press ^C to stop.
Your MySQL connection id is 16 (X protocol)
Server version: 8.0.21 MySQL Community Server - GPL
No default schema selected; type \use to set one.
MySQL 192.168.5.94:33060+ ssl JS >
Bye!

As you could see, no …

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MySQL 8.x DDL Rewriter and Query Rewriter Plugins: Implementation and Use Cases

Rewriting a MySQL query for performance is an important process that every DBA should be aware of so they can fix the wrong queries on runtime without code changes on the application end. ProxySQL has great support for rewriting the queries, which Alkin Tezuysal already explored in his excellent blog ProxySQL Query Rewrite Use Case.

So far, MySQL community provides two built-in query rewrite plugins to perform this task. Recently they introduced the plugin “ddl_rewriter”.

  • query rewriter plugin : It has support for INSERT / UPDATE / DELETE / REPLACE statements from MySQL 8.0.12. 
  • ddl_rewritter plugin: It supports the CREATE TABLE statement. Introduced at MySQL 8.0.16.

In this blog, I am going to explain the complete process of the implementation and the …

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Finding a Regression in MySQL Source Code: A Case Study

At the Percona engineering team, we often receive requests to analyze changes in MySQL/Percona Server for MySQL behavior from one version to another, either due to regression or a bug fix (when having to point out to a customer that commit X has fixed their issue and upgrading to a version including that fix will solve their problem).

In this blog post, we will analyze the approach used to fix PS-7019 – Correct query results for LEFT JOIN with GROUP BY.

Each release comes with a lot of changes. For example, the difference between MySQL 8.0.19 to 8.0.20:

git diff mysql-8.0.19..mysql-8.0.20 | wc -l
737454
git diff mysql-8.0.19..mysql-8.0.20 --name-only | wc -l
4495

737K lines in 4495 files have changed from one minor version to another.

git …
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MySQL Shell Dump & Load part 4: Dump Instance & Schemas

MySQL Shell 8.0.21 comes with two utilities which can be used to perform logical dumps of all the schemas from an instance (util.dumpInstance()) or selected schemas (util.dumpSchemas()). These tools offer major performance improvements over the mysqldump utility, some of our benchmarks show a throughput up to 3GB/s!…

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How Can ScaleFlux Handle MySQL Workload?

Recently I had the opportunity to test a storage device from ScaleFlux called CSD 2000. In this blog post, I will share the results of using it to run MySQL in comparison with an Intel device that had a similar capacity.

First of all, why do we need another storage device? Why is ScaleFlux any different?

The answer is simple; it gives us built-in compression and atomic writes. For many workloads, but especially for database-type workloads, these are very important features.

Because of built-in compression, we can store more data on the ScaleFlux device than on a similar device with the same capacity.

Because of atomic writes, we can disable InnoDB Double Write buffer which means less writes/fsync on the disk layer. This should give us a performance advantage against non-atomic drives.

I ran many different tests on different data sizes, with different …

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Improvements to Undo Truncation in MySQL 8.0.21

Undo Tablespaces can be truncated either implicitly or explicitly in MySQL 8.0. Both methods use the same mechanism. This mechanism could cause periodic stalls on very busy systems while an undo tablespace truncate completes. This problem has been fixed in MySQL 8.0.21.…

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Getting core files and systemd Restart

So you have waited two weeks (cause the crash isn’t easily repeatable) and finally you get the crash again. You check your non-datadir core file directory with loads of free space and discover nothing was written. When MySQL crashes, you … Continue reading →

Top Blog Posts about MySQL 8.0.21

As with any new releases, MySQL 8.0.21 introduces many new improvements and updates, many of which deserve their own blog post for a deep dive into the new features.  Among the notable changes are: Account Management Notes, JSON Notes, Authentication Notes and changes related to InnoDB, Optimizer, Group Replication, and more.

Here are the MySQL 8.0.21 top blog posts:

Server:
- The MySQL 8.0.21 Maintenance Release is Generally Available
- MySQL 8.0 – Who stopped mysqld and how long did it take?
- MySQL: who’s filling my error log?

Shell:
- …

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MySQL Shell Dump & Load part 3: Load Dump

Introduced in MySQL Shell 8.0.21, the new MySQL Shell Dump and Load utilities has as its main goal to minimize the time needed to create and restore logical dumps of large data sets.

Through heavy parallelization and other techniques, we were able to reduce the time needed for these tasks by an order of magnitude compared to previous dump utilities.…

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