Showing entries 1 to 10 of 1303
10 Older Entries »
Displaying posts with tag: Linux (reset)
MySQL Script Test

There are many ways to test and edit files. A lot of developers only use their favorite Integrated Developer Environment (IDE) but I find testing script files within the scope of a pipelined set of scripts much faster.

The ability to edit a script from within the MySQL Command-Line Interface (CLI) or MySQL Shell would be nice but unfortunately, doesn’t exist. You can always subshell to edit a file or list files in the present working directory, like:

mysql> \! vi task.sql

I prefer to test at the OS level while leveraging the up-arrow key for command history. Here’s my quick edit and test script technique from your present working directory:

  1. Assume you create a task.sql test file, like:
    SELECT user() AS "Current User"\G
    
  2. You can edit with vi or emac and test the script interactively from the present working directory.
[Read more]
MySQL Transaction Scope

The idea of ACID transactions are a basic feature of SQL’s individual Data Manipulation Language (DML) commands, like the INSERT, UPDATE, and DELETE statements. Transactions across two or more tables are a natural extension of ACID compliance features provided by DML commands. However, they require a structured programming approach, like a store procedure or like API implemented in an imperative language.

Surprisingly, transaction management wasn’t covered well in Alan Beaulieu’s Learning SQL because he only provided pseudo code logic. While I thought troubleshoot some broken MySQL SQL/PSM logic would be a good learning experience for students, it wasn’t. So, I wrote this sample code to show how to achieve an all or nothing transaction across four tables.

The code for this example on transaction management lets you perform the important tasks necessary to effect transaction …

[Read more]
How to create Cloudwatch alarms for RDS (MySQL) on AWS

Monitoring your RDS instances is very important, and the same applies to other resources. In this article, we will create a simple alarm for an RDS MySQL instance which will check for free storage space on the instance.

MySQL macOS Docker

While you can download MySQL as a DMG package, a number of users would prefer to install it as a Docker instance. You won’t find the macOS downloads on the same web site as other downloads. You can use the following macOS download site.

After installing Docker on your macOS, you can pull a copy of the current MySQL Server with the following command:

docker pull mysql/mysql-server

You should create a mysql directory inside your ~/Documents directory with this command:

mkdir ~/Documents/mysql

Then, you should use the cd command to change into the ~/Documents/mysql directory and run this command:

pwd

It should return the following directory: …

[Read more]
dim_STAT : v.9.0 CoreUpdate-20-12

Just realized I did not post any notes about dim_STAT CoreUpdates during the last 3 years, so will try to fix it now with the following short summary ;-))

Read more... (2 min remaining to read)

MinervaDB Athena 2020 – Profiling Linux Operations for Performance and Troubleshooting by Tanel Poder

MinervaDB Athena 2020 – Profiling Linux Operations for Performance and Troubleshooting by Tanel Poder

In Athena 2020, Tanel Poder talked about troubleshooting Linux operations performance based on the detailed forensics and evidence collection through0x.tools (Linux Process Snapper from Tanel), Which is a free, open source /proc file system sampling tool which annotates Linux thread handling activities more intuitively. The talk was really interesting for Open Source Database Systems folks who attended the conference because they spend most of their professional hours troubleshooting performance of their Database Infrastructure Operations for optimal performance and also in this talk Tanel’s approach was bottom-up (interpreting performance metrics with Linux probes) compared top-down approach (depending on Database Systems metadata views), You can download the PDF of the talk

[Read more]
How to take and restore a snapshot on AWS RDS MySQL Instance

In this article, we will see the steps to create a snapshot of the existing RDS MySql Instance. Then we will see the steps to restore the snapshot which creates a new RDS Instance. At last, we will clean up the instances and snapshots.

MySQL Self-Join

I’m switching to MySQL and leveraging Alan Beaulieu’s Learning SQL as a supporting reference for my Database Design and Development course. While reviewing Alan’s Chapter 5: Querying Multiple Tables, I found his coverage of using self-joins minimal.

In fact, he adds a prequel_film_id column to the film table in the sakila database and then a single row to demonstrate a minimal self-join query. I wanted to show them how to view a series of rows interconnected by a self-join, like the following:

SELECT   f.title AS film
,        fp.title AS prequel
FROM     film f LEFT JOIN film fp
ON       f.prequel_id = fp.film_id
WHERE    f.series_name = 'Harry Potter'
AND      fp.series_name = 'Harry Potter'
ORDER BY f.series_number;

It returns the following result set:

[Read more]
Conditional Updates

While I’m switching labs next term after more than a decade with more comprehensive lab set, I’m hoping the new exercises build the students’ core SQL skill set. Next term, I hope to see whether the change is successful. I’ve opted for using Alan Beaulieu’s Learning SQL: Generate, Manipulate, and Retrieve Data, 3rd Edition, because it’s a great book and uses the MySQL database.

One exercise that the students will lose is a data migration exercise from a badly designed common_lookup table to a well designed common_lookup table. The starting point is shown below on the left and the fixed version is on the right.

         …

[Read more]
MySQL Unicode Warning

It’s always interesting when I upgrade from one release to the next. I learn new things, and in the case of MySQL’s installation and maintenance I become more grateful for the great team of developers working to produce MySQL 8.

A warning that caught my eye in MySQL 8 (8.0.21) was this one on Unicode with the utf8 character code:

Warning (code 3719): 'utf8' is currently an alias for the character set UTF8MB3, but will be an alias for UTF8MB4 in a future release. Please consider using UTF8MB4 in order to be unambiguous.

Currently, a character alias for utf8mb3 is an alias for the deprecated utf8mb3 (a 3-byte character set) until it is removed. When the utf8mb3 character set is …

[Read more]
Showing entries 1 to 10 of 1303
10 Older Entries »