Recently, while doing a test process to examine resource usage and the time required to alter the table using pt-osc, it leads to a loss of triggers even though the –preserve-triggers option is specified. I made the decision to recreate the identical circumstance so that everyone could see it.

Test environment : 

OS: Amazon Linux 2

MySQL version: 5.7.40

pt-online-schema-change version: 3.1.0

Before digging deeper, we must first obtain the whole picture. Here is an illustration of the table’s structure.

Table structure:

This is an update for MySQL 8 Stored PSM to add the ONLY_FULL_GROUP_BY mode to the global SQL_MODE variable when it’s not set during a session. Here’s the code:

/* Drop procedure conditionally on whether it exists already. */
DROP PROCEDURE IF EXISTS set_full_group_by;

/* Reset delimter to allow semicolons to terminate statements. */
DELIMITER $$

/* Create a procedure to verify and set connection parameter. */
CREATE PROCEDURE set_full_group_by()
  LANGUAGE SQL
  NOT DETERMINISTIC
  SQL SECURITY DEFINER
  COMMENT 'Set connection parameter when not set.'
BEGIN

  /* Check whether full group by is set in the connection and
     if unset, set it in the scope of the connection. */
  IF EXISTS
    (SELECT TRUE
     WHERE NOT REGEXP_LIKE(@@SESSION.SQL_MODE,'ONLY_FULL_GROUP_BY'))
  THEN
    SET @@GLOBAL.SQL_MODE := CONCAT(@@SESSION.sql_mode,',ONLY_FULL_GROUP_BY');
  END IF;
END;
$$

/* Reset the default delimiter. */
DELIMITER ;

You can call the …

Knex recently released a new version this week (2.4.0). Before this version, Knex had a pretty scary SQL injection. Knex currently has 1.3 million weekly downloads and is quite popular.

The security bug is probably one of the worst SQL injections I’ve seen in recent memory, especially considering the scope and popularity.

If you want to get straight to the details:

• Check out the Github issue, which was opened 7 years ago(!)
• An article from Ghostccamm explaining the vulnerability.
• CVE-2016-20018.

My understanding of this bug

If I understand the vulnerability correctly, I …

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.