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Displaying posts with tag: MySQL (reset)
A graph a day, keeps the doctor away ! – Full Table Scans

Full table scans can be problematic for performance. Certainly if the scanned tables are large. The worst case is when full table scans are involved in joins and particularly when the scanned table is not the first one (this was dramatic before MySQL 8.0 as Block Nested Loop was used) !

A full table scans means that MySQL was not able to use an index (no index or no filters using it).

Effects

When Full Table Scans happen (depending of the size of course), a lot of data gets pulled into the Buffer Pool and maybe other important data from the working set is pulled out. Most of the time that new data in the Buffer Pool might even not be required by the application, what a waste of resources !

You then understand that another side effect of Full Table Scans is the increase of I/O operations.

The most noticeable symptoms of Full Table Scans are:

  • increase of CPU usage
  • increase of …
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MySQL WHERE Clause Equality Comparison Operator

We don’t always need all rows from the table as part of the final results set. You can use one (or more) of the comparison operators to filter the rows with a WHERE clause conditional. In this post, we are looking at the equality comparison operator (=)…

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

Image by kalhh from  …

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OpenLampTech issue #30 – Substack Repost

I’m back again this week with your MySQL, PHP, and LAMP stack media outlet source. There are plenty of great reads in this week’s OpenLampTech newsletter. Enjoy and please share the publication.

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

There is something for everyone in OpenLampTech issue #30. We have articles covering:

  • 20 Laravel tips
  • Ignore FSE
  • Sorting arrays in PHP
  • Linux useradd and adduser commands
  • SQL engineering guide
  • And much much more…

Don’t …

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Is SQL Programming


Is SQL, or Structured Query Language, a programming language? That’s a great question! A question that many answer with emphasis: “No, SQL is not a programming language!” There are some who answer yes; and they usually qualify that answer with something like: “SQL is a programming language designed to communicate with relational databases.”

It strikes me that those saying “yes” are saying that SQL is only a collection of interface methods to read from and write to a database engine. Those saying SQL is not a programming language often qualify that a programming language must have conditional logic and iterative structures, which don’t exist in SQL.

There’s a third group that are fence sitters. They decline to say whether SQL is a programming language, but they also say individuals who only write SQL aren’t programmers. That’s a bit harsh from my perspective.

Before …

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Node.js MySQL Error

While I blogged about how to setup Node.js and MySQL almost two years ago, it was interesting when a student ran into a problem. The student said they’d configured the environment but were unable to use Node.js to access MySQL.

The error is caused by this import statement:

const mysql = require('mysql') 

The student got the following error, which simply says that they hadn’t installed the Node.js package for MySQL driver.

internal/modules/cjs/loader.js:638
    throw err;
    ^

Error: Cannot find module 'mysql'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
    at Function.Module._load (internal/modules/cjs/loader.js:562:25)
    at Module.require (internal/modules/cjs/loader.js:692:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at Object. (/home/student/Data/cit325/oracle-s/lib/Oracle12cPLSQLCode/Introduction/query.js:4:15)
    at Module._compile …
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Vitess at KubeCon+CloudNativeCon EU 2022

Kubecon+CloudNativeCon EU 2022 # When: May 16-20 Who: Deepthi Sigireddi, Harshit Gangal, Manan Gupta What: Vitess project booth, maintainer talk, office hours Event Details # May 16-17 were co-located events. We were there for the main conference which was May 18-20. There were 7000+ attendees. The Vitess team were attending in their capacity as project maintainers to staff a booth in the Project Pavilion, hold office hours and to give a talk.

Explore & visualize your MySQL HeatWave data with Superset

In this article I will show you how to properly configure Apache Superset in order to take advantage of a high performance, in-memory query accelerator: MySQL HeatWave.

The post Explore & visualize your MySQL HeatWave data with Superset first appeared on dasini.net - Diary of a MySQL experts.

MySQL DATE() Function with examples

The MySQL DATE() function is a built-in function you use to extract just the date portion from a DATE or DATETIME value. Learn how to use the DATE() function in this blog post…

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

Image by MaeM from Pixabay

MySQL DATE() Function Syntax

The …

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OpenLampTech issue #29 – Substack Repost

The OpenLampTech newsletter is going to the next level with more content than you can imagine so stay tuned! Enjoy this week’s newsletter and share this edition. Thank you for reading the publication!

The Newsletter for PHP and MySQL Developers

Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.

Get ready for great MySQL, PHP, and LAMP stack content. In this week’s OpenLampTech issue #29 newsletter we have articles on:

  • The Linux passwd file
  • 5 PHP tips to write better code
  • Another top-notch video on WordPress Full Site Editing
  • 17 Laravel performance tips …
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MyDumper’s Stream Implementation

As you might know, mysqldump is single-threaded and STDOUT is its default output. As MyDumper is multithreaded, it has to write on different files. Since version 0.11.3 was released in Nov 2021, we have the possibility to stream our backup in MyDumper. We thought for several months until we decided what was the simplest way to implement it and we also had to add support for compression. So, after fixing several bugs, and we now consider it is stable enough, we can explain how it works.

How Can You Stream if MyDumper is Multithreaded?

Receiving a stream is not a problem for myloader, it receives a file at a time and sends it to a thread to process it. However, each worker thread in mydumper is connected to the database, and as soon as it reads data, it should be sent to the stream, which might cause collisions with other worker threads that are reading data from the database. In order to avoid this issue, we ended up with the …

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