Follow this guide to troubleshoot Inboud Replication Channel to OCI MySQL HeatWave Database Service if replication is not running

First introduced to MySQL in version 8.013, functional indexes give us the ability to create indexes based on expressions rather than the values of data in a database column. In this post we discuss how to create functional indexes as well as some limitations and implications with their use.

What is MySQL Connection Control and how to use it.

Developers have been storing JSON data in MySQL databases since before the JSON data type existed. With the introduction of functional indexes, developers can now create indexes based on values in data stored in a column with the JSON data type.

Looking at how people are using COUNT(*) and COUNT(col), it looks like most of them think they are synonyms and just use what they happen to like, while there is a substantial difference in performance and even query results. Also, we find a difference in execution on InnoDB and MyISAM engines.

NOTE: All tests were applied for MySQL version 8.0.30, and in the background, I ran every query three to five times to make sure that all of them were fully cached in the buffer pool (for InnoDB) or by the filesystem (for MyISAM).

Count function for Innodb engine:

Let’s have look at the following series of examples for InnoDB engine:

CREATE TABLE count_innodb (
  id int(10) unsigned NOT NULL AUTO_INCREMENT,
  val_with_nulls int(11) default NULL,
  val_no_null int(10) unsigned NOT NULL,
  PRIMARY KEY idx (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

(mysql) > select count(*) from count_innodb; …

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In OpenLampTech issue #60, we are looking at some fantastic articles covering:

• Laravel Eloquent and Query Builder tips
• Drupal’s updated CKEditor 5
• How Symfony powers Drupal
• Best SQL Editors
• WooCommerce Payment Gateways
• And much more

Want to help OpenLampTech be a success …

If you have data stored in a Microsoft SQL Server database and you want to import it into MySQL HeatWave Database Service in OCI, you can use the procedure described in this article.

There are several ways you can try to speed up a MySQL replica. Here are some ideas:

What is MySQL InnoDB Redo Log Archiving ? How does it work ? Discover this important MySQL InnoDB feature reading this blog post.

Live Migration from Azure Database for MySQL to MySQL HeatWave Database Service on Oracle Cloud (OCI)