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Displaying posts with tag: MySQL 8.0 (reset)
MySQL ERROR Log Table Explained

Over the decades we have been reading the MySQL error log from the server system file, if there are any issues in MySQL or any unknown restart happened , generally we look at the mysql error log.

By default MySQL error log can be found in the default path /var/log/mysqld.log , or it can be explicitly configured using the variable log_error.

Few drawbacks using MySQL error log as FILE

  • Possibility of missing genuine errors while reading lengthy information.
  • Filtering of errors for the particular date and timeframes.
  • Cannot provide the DB server access to developers because of fear of mishandling DB servers.

To overcome the above issues , from MySQL …

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How to copy a MySQL user to OCI MDS ?

When you migrate to MySQL Database Service on Oracle Cloud Infrastructure (MDS on OCI), the easiest, fastest and recommended way it to use MySQL Dump & Load Utility.

For more information check these different links:

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Make way for the High Performance Parallel Dump & Load Utilities + How to use them

MySQL-Shell has had a set of “Util” object functions for almost a year as of this post. It is this added functionality that negates any reason someone would still need to use the old mysqldump client. It (mysqldump) helped the MySQL Community for a long, long time. It also introduced a large amount of garbage and messiness in… Read More »

Using OpenVPN with MySQL Database Service

I’ve already provided some solutions to connect to your MDS instance, using MySQL Router, SSH tunnel, … but one of the best way if you have multiple instance to manage, is to use a VPN.

This post summarize the steps on how to deploy Open VPN and configure your VCN to use it.

So, in OCI, we have already some MDS & Compute instances deployed, this is how the dashboard looks like:

OpenVPN Deployment

We can start by deploying our OpenVPN instance using OCI’s Marketplace:

And you follow the wizard by adding your administrator username and password:

An important step is to use the existing VCN and place the OpenVPN in the public subnet:

And you create the instance:

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Deploy WordPress on OCI using MDS – updated version

This blog post was first published on FoggyKitchen.com.

Hello fine gourmets, for my first dish in the FoggyKitchen.com, I decide to present you how to deploy WordPress on OCI using MySQL Database Service aka MDS.

I wrote some Terraform recipes that you can find on my GitHub repository: oci-wordpress-mds.

In this first post, I will show how easy it’s to deploy directly from OCI’s dashboard using Resource Manager’s stack. I will also share the recent additions.

The first think to do is to download the stack in releases from GitHub:

When the zip file is downloaded locally, you can login in …

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Fastest Parallel replication method in MySQL 8.

From MySQL 5.7, we had a Multi-threaded Slave (MTS) Applier mechanism called LOGICAL_CLOCK to overcome the problems of parallel replication within a database.

To further improve the parallelisation mechanism, from MySQL 8 (5.7.22) we have write-set replication, so before going further , lets look at the difference between Logical clock (LC) and Writeset.

LOGICAL_CLOCK

Transactions that are part of the same binary log group commit on a master are applied in parallel on a slave. The dependencies between transactions are tracked based on their timestamps to provide additional parallelisation where possible.

WRITESET

Write-set is a mechanism to track independent transactions that can be executed in parallel in the slave. Parallelising on write sets has potentially much more parallelism than logical_clock ,since it does not depend …

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MySQL Query Attributes

Tweet

Query attributes have in a long time been used to add metadata to queries to provide additional context such as where in the application the query was generated. The traditional way to do this is to add a comment at the start of the query with the attributes. Since the MySQL parser ignores the comment, it does not change the semantics of the query, but various tools can extract the comments.

This post looks into the reasons for using query attributes, how it is done using a comment, and the new component for MySQL 8.0.23 that provides native support for query attributes.

Advice

Query attributes are also known as query tags.

Why Query Attributes?

At the surface, it may seem that there is no major benefit from having metadata …

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MySQL Invisible Column: part III

We recently saw how the new Invisible Column feature works in MySQL since 8.0.23 and how we can use it as a Primary Key for InnoDB tables when no Primary Key was defined.

As I wrote earlier, a good Primary Key is important for InnoDB (storage, IOPS, secondary indexes, memory…) but there is another important domain where a Primary Key is important in MySQL: replication !

Asynchronous Replication

When using “traditional” replication, if you modify a record (UPDATE and DELETE), the record(s) to modify on the replica are identified using indexes, and of course the Primary Key if any. The hidden global 6-bytes auto generated by InnoDB primary key is never used as never exposed and as it’s global, …

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MySQL Invisible Column: part II

This article is the second part of the series related to MySQL Invisible Column started here.

This post covers why Invisible Column is important for InnoDB Storage Engine.

To start, let me explain briefly how InnoDB deals with Primary Key and why an good primary key is important. And finally, why having a Primary Key is also important.

How does InnoDB Stores Data?

InnoDB stores data in table spaces. The records are stored and sorted using the clustered index (the primary key): they are called index-organized tables.

All secondary indexes also contain the primary key as the right-most column in the index (even if this is not exposed). That means when a secondary …

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MySQL Invisible Column – part I

With the new MySQL 8.0.23, something very interesting has been released: Invisible Column.

This is the first post dedicated to this new feature, I expect to write a series of 3. This one is the introduction.

Prior to MySQL 8.0.23, all columns of a table were always visible (if you had the privilege to see it). Now, an invisible column can be specified and will be hidden to queries. It can always be accessed if explicitly referenced.

Let’s see how it works:

create table table1 (
   id int auto_increment primary key, 
   name varchar(20), 
   age int invisible);

In the table description we can see the INVISIBLE keyword in the Extra column:

desc table1; …
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