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Displaying posts with tag: Percona Server for MySQL (reset)
Session Temporary Tablespaces and Disk Space Usage in MySQL

Temporary Tables handling in MySQL has a somewhat checkered past. Some time ago, my colleague Przemek wrote a post about differences in the implementations between versions of MySQL. If you are looking for the differences in implementation, that’s a perfect place to check.

In this post, I’d like to focus on Session Temporary Tablespaces, InnoDB on-disk internal temporary tables that come to play when a query requires storing more data than tmp_table_size or TempTable engine allocated more than …

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Spring Cleaning: Discontinuing RHEL 6/CentOS 6 (glibc 2.12) and 32-bit Binary Builds of Percona Software

As you are probably aware, Red Hat Enterprise Linux 6 (RHEL 6 or EL 6 in short) officially reached “End of Life” (EOL) on 2020-11-30 and is now in the so-called Extended Life Phase, which basically means that Red Hat will no longer provide bug fixes or security fixes.

Even though EL 6 and its compatible derivatives like CentOS 6 had reached EOL some time ago already, we continued providing binary builds for selected MySQL-related products for this platform.

However, this became increasingly difficult, as the MySQL code base continued to evolve and now depends on tools and functionality that are no longer provided by the operating system out of the box. This meant we already had to perform several modifications in order to prepare binary builds for this platform, e.g. installing custom compiler versions or newer versions of various system …

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Using Percona Server for MySQL 8.0 and Percona XtraBackup 8.0 with HashiCorp Vault Enterprise KMIP Secrets Engine

KMIP (Key Management Interoperability Protocol) is an open standard developed by OASIS (Organization for Advancement of Structured Information Standards) for the encryption of stored data and cryptographic key management.

Percona Server for MySQL 8.0.27 and Percona XtraBackup 8.0.27 now include a KMIP keyring plugin to enable the exchange of cryptographic keys between a key management server and the database for encryption purposes. The procedure to use them with HashiCorp Vault Enterprise is described below.

Install Hashicorp Vault Enterprise

We will first install Hashicorp Vault Enterprise on Ubuntu Linux “Bionic” and then enable …

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Attack No-PK Replication Lag with MySQL/Percona Server 8 Invisible Columns!

The most common issue when using row-based replication (RBR) is replication lag due to the lack of Primary keys.

The problem is that any replicated DML will do a full table scan for each modified row on the replica. This bug report explains it more in-depth: https://bugs.mysql.com/bug.php?id=53375

For example, if a delete is executed on the following table definition:

CREATE TABLE `joinit` (
  `i` int NOT NULL,
  `s` varchar(64) DEFAULT NULL,
  `t` time NOT NULL,
  `g` int NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1

 

With this amount of rows:

mysql> select count(*) from joinit;
+----------+
| count(*) |
+----------+
|  1048576 |
+----------+

 

The delete being:

mysql> flush status ;

mysql> delete from joinit where i > 5 and i < 150;
Query OK, 88 rows affected (0.04 sec) …
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Reminder: TokuDB Storage Engine Will Be Disabled by Default in Percona Server for MySQL 8.0.26

As we’ve communicated in our blog post in May, the TokuDB Storage Engine has been marked as “deprecated” in Percona Server for MySQL 8.0. It will be removed in a future version (Percona Server for MySQL 8.0.28, expected to ship in Q1 2022).

With the release of Percona Server for MySQL 8.0.26, the storage engine will still be included in the binary builds and packages but will be disabled by default. If you are upgrading from a previous version, the TokuDB Storage Engine plugin will fail with an error message at server startup if it is installed.

You will still be able to re-enable it manually so that you can perform the necessary migration steps.

Re-enabling the TokuDB …

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Repoint Replica Servers in MySQL/Percona Server for MySQL 8.0

When doing migrations or failovers in MySQL, there is usually a need to do a topology change and repoint replica servers to obtain replication data from a different server.

For example, given servers {A, B, and C} and the following topology:

If you need to repoint C to be a replica of B, i.e:

You can follow the next steps:

Note: log_replica_updates should be enabled on the soon-to-be primary as it is a prerequisite for chain replication.

Note: It is assumed that both replicas only stream from Server A and there are no conflicting replication filters in place that might break replication later on.

If Using File/Position-Based Replication:

1) Stop B and C

STOP REPLICA;

2) If replicas are multi-threaded, correct MTS gaps and make them …
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Skipping Percona Server for MySQL Version 8.0.24 and Releasing 8.0.25 Next

After Oracle released MySQL version 8.0.24 on April 20, 2021, our engineering team got started right away with merging our enhancements to prepare the corresponding 8.0.24 version of Percona Server for MySQL.

However, Oracle released MySQL version 8.0.25 shortly afterward on May 11, 2021, to fix a critical bug that we also observed during our initial testing and reported back to them.

Therefore, we have decided to skip releasing Percona Server for MySQL 8.0.24 both as a standalone product and a distribution as well as the …

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Online DDL with Group Replication In Percona Server for MySQL 8.0.22 (and MySQL 8.0.23)

While I was working on my grFailOver POC, I have also done some additional parallel testing. One of them was to see how online DDL is executed inside a Group Replication cluster.

The online DDL feature provides support for instant and in-place table alterations and concurrent DML. Checking the Group Replication (GR) official documentation, I was trying to identify if any limitation exists, but the only thing I have found was this:

“Concurrent DDL versus DML Operations.  Concurrent data definition statements and data manipulation statements executing against the same object but on different servers is not supported when using multi-primary mode. During execution of Data Definition Language (DDL) statements on an object, executing concurrent Data Manipulation Language (DML) on the …

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Which Version of MySQL Should I Use for MyRocks?

As database footprints continue to explode, many companies are looking for ways to deal with such rapid growth.  One approach is to refactor traditional relational databases to fit into a NoSQL engine, where horizontal scalability is easier.  However, in many cases, this is in no way a trivial undertaking.

Another approach that has been gaining interest is the use of MyRocks as an alternative storage engine to the traditional InnoDB.  While not for everyone, in certain use cases it could be a potential solution.  As with so many things open source, the next standard questions are: which version should I use?  Any differences with the engine if I use MyRocks with MySQL 5.7 vs 8.0?

In this post, I wanted to touch on this and give some high-level thoughts on MyRocks when it comes to the version of MySQL.

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Working to Validate MyRocks in the Enterprise with Dropbox

Percona Technical Account Managers get the privilege of working with some of our largest enterprise clients day in and day out.  As such, we get to really focus on how to best leverage our technology to generate measurable benefits for our users.  While it is fun to “nerd out” and always strive to use the latest and greatest, we need to stay focused on demonstrating business value and a genuine need.  Over the past few months, I’ve been working with one of my larger clients, Dropbox, along with our professional services team to validate the use of Percona Server for MySQL with the MyRocks storage engine over a large portion of their MySQL infrastructure.

Please note – this is not meant to be a deep dive into the technical details around …

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