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Making Sense of MySQL Group Replication Consistency Levels

From the initial release, one of the biggest complaints I had about Group Replication is that it allowed “stale” reads and there was no way to prevent them or to even know that you read “stale” data. That was a huge limitation. Thankfully, Oracle released features to control the consistency levels, and it was exactly a year ago! I don’t know about you, but I personally was confused by naming it group_replication_consistency=’AFTER’ or ‘BEFORE’.

So now I want to try to make sense of it and share my understanding (even if it is one year later).

Setup:

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How to Install MySQL Enterprise Edition on Docker and Monitor it with MySQL Enterprise Monitor(MEM)?


Introduction
Before I talk about installation of MySQL inside docker, it's more important to know
what is Docker?
- Docker is a tool designed to create , deploy ,and run an application any where.
-It allow us to package up application with all requirements such as libraries and other dependencies and ship it all as a PACKAGE.
who uses Docker?
Developer : Docker enables developer to develop application without spending much time on IT infrastructure.
Sysadmin :-Docker enables sysadmin to streamline the software delivery, such as develop and deploy bug fixes and new features without any roadblock. 
Enterprise :-Docker works in the cloud , on premise ,and supports both traditional …

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InnoDB Flushing in Action for Percona Server for MySQL

As the second part of the earlier post Give Love to Your SSDs – Reduce innodb_io_capacity_max! we wanted to put together some concepts on how InnoDB flushing works in recent Percona Server for MySQL versions (8.0.x prior to 8.0.19, or 5.7.x). It is important to understand this aspect of InnoDB in order to tune it correctly. This post is a bit long and complex as it goes very deep into some InnoDB internals.

InnoDB internally handles flush operations in the background to remove dirty pages from the buffer pool. A dirty page is a page that is modified in memory but not yet flushed to disk. This is done to lower the write load and the latency of the transactions. Let’s explore the various sources of flushing inside InnoDB.

Idle Flushing

We already discussed the idle flushing in the previous post …

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Automatic Schema Synchronization in NDB Cluster 8.0: Part 2

In part 1, we took a brief, high-level look at the various protocols and mechanisms used to keep the Data Dictionary (DD) of MySQL servers connected to a MySQL Cluster in synchronization with each other and with the NDB Dictionary.…

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Troubleshooting an OLAP system on InnoDB

As a part of Mydbops Consulting we have a below problem statement from one of our client.

We have a high powered server for reporting which in turn powers our internal dashboard for viewing the logistics status.Even with a high end hardware, we had a heavy CPU usage and which in turn triggers spikes in replication lag and slowness. Below is the hardware configuration.

OS : Debian 9 (Stretch)
CPU : 40
RAM : 220G (Usable)
Disk : 3T SSD with 80K sustained IOPS.
MySQL : 5.6.43-84.3-log Percona Server (GPL)
Datasize : 2.2TB

Below is the graph on CPU utilisation from Grafana.

Since the work load is purely reporting(OLAP) we could observe a similar type of queries with different ranges. Below is the Execution plan of the query. It is a join query over 6 tables.

Explain Plan:

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Moving from MySQL 5.7 to MySQL 8.0 - What You Should Know

April 2018 is not just a date for the MySQL world. MySQL 8.0 was released there, and more than 1 year after, it’s probably time to consider migrating to this new version.

MySQL 8.0 has important performance and security improvements, and, as in all migration to a new database version, there are several things to take into account before going into production to avoid hard issues like data loss, excessive downtime, or even a rollback during the migration task.

In this blog, we’ll mention some of the new MySQL 8.0 features, some deprecated stuff, and what you need to keep in mind before migrating.

What’s New in MySQL 8.0?

Let’s now summarize some of the most important features mentioned in the official documentation for this new …

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Debezium MySQL Snapshot For CloudSQL(MySQL) From Replica

The snapshot in Debezium will do a historical data load from the source database to the Kafka topics. But generally its not a good practice to this if you have a huge data in your tables. Recently I have published many blog posts to perform this snapshot from Read Replica(with/without GTID, AWS Aurora). One guy commented that, in GCP the MySQL managed service is called CloudSQL. There we don’t have much control to stop replication, perform the modifications that we want. So how can we avoid snapshots in CloudSQL and take debezium snapshots from CloudSQL Read Replica? I have spent some time today and figured out a way to do this.

The Approach:

We can’t enable binlogs on read replica. So we have to setup an external read replica for this. If the external replica is a VM, then we can enable the log-slave-updates with GTID. Then we can …

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Faster restarts with local and partial checkpoints in MySQL NDB Cluster

The MySQL NDB Cluster team works on fundamental redesigns of core parts of NDB architecture. One of these changes is the partial checkpoint algorithm. You can now take full advantage of it when building much larger clusters: NDB 8.0 can use 16 TB data memory per data node for in-memory tables.

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Automatic Schema Synchronization in NDB Cluster 8.0: Part 1

Data nodes are the distributed, sharded storage core of MySQL NDB Cluster. Its data is usually accessed by MySQL Servers (also called SQL nodes in NDB parlance). The MySQL servers each have their own transactional Data Dictionary (DD) where all the metadata describing tables, databases, tablespaces, logfile groups, foreign keys, and other objects are stored for use by MySQL server.…

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FOSDEM MYSQL COMMUNITY DINNER – FRIDAY 31 JAN 2020

There are certain things in life that you can count on …

FOSDEM is back in town, and together with that a new pre-FOSDEM MySQL day, actually 2 days this year!

And of course, we definitely have not forgotten … the MySQL Community dinner!

We continue the by now well known tradition of dining together in style with members from all over the community, and invite you to the ICAB venue (the same location as where the pre-FOSDEM MySQL days are being held.

Book your tickets now!!!

The listed ticket price includes a selection of Belgian …

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