19 Jan 2021

feedPlanet Ubuntu

Alan Pope: Embarrassing Bugs

Well, this is embarrassing! I recently filed a bug against an open source project because I genuinely thought it was broken. It was (almost, probably, entirely) my fault. I thought I'd fess up and explain what happened. It might be useful for others. As I mentioned yesterday, I recently upgraded my Ubuntu machines, including my main desktop. It's a funky Skull Canyon NUC with a weird hybrid Intel / AMD GPU setup and an external nVidia card in an enclosure.

19 Jan 2021 12:00pm GMT

Ubuntu Blog: What is PostgreSQL and why do enterprise developers and start-ups love it?

<noscript> <img alt="" height="443" src="https://res.cloudinary.com/canonical/image/fetch/f_auto,q_auto,fl_sanitize,c_fill,w_589,h_443/https://ubuntu.com/wp-content/uploads/d8ca/databasemodel.jpg" width="589" /> </noscript>

PostgreSQL is a powerful, open source object-relational database system that is known for reliability, feature robustness, and performance. PostgreSQL is becoming the preferred database for more and more enterprises. It is currently ranked #4 in popularity amongst hundreds of databases worldwide according to the DB-Engines Ranking. An enterprise class database, PostgreSQL boasts sophisticated features such as Multi-Version Concurrency Control (MVCC), point in time recovery, tablespaces, asynchronous replication, nested transactions, online/hot backups, a sophisticated query planner/optimiser, and write ahead logging for fault tolerance.

What is PostgreSQL?

PostgreSQL is a relational database. It stores data points in rows, with columns as different data attributes. A table stores multiple related rows. The relational database is the most common type of database in use. It differentiates itself with a focus on integrations and extensibility. It works with a lot of other technologies and conforms to various database standards, that ensure it is extensible.

Let's dig deeper into why it is still relevant today, in a time of big-data, time-series and unstructured data.

Why use PostgreSQL?

The reliable database

Databases need to be in a known state - either a change was made, or was not made. Otherwise, data integrity and accuracy is compromised. The problem is, databases can be slow to update, especially if the backing store is older, cheaper storage. Slow means there is more time for something to go wrong and break accuracy and integrity. PostgreSQL uses two killer features to ensure reliability.

Second, it replicates databases with ease, and with native support of asynchronous and synchronous replication. This lets users have a highly available database, where a server going down does not mean data loss. PostgreSQL achieves this using the log we mentioned above - the log is distributed to other nodes so that other nodes remember the change.

The extensible database

There are two areas that PostgreSQL shines when users need to configure and control their database. First, it is compliant to a high degree with SQL standards. This increases it's interoperability with other applications.

Second, PostgreSQL gives users control over the metadata. PostgreSQL is extensible because its operation is catalog-driven. One key difference between PostgreSQL and standard relational database systems is that PostgreSQL stores much more information in its catalogs: not only information about tables and columns, but also information about data types, functions, access methods, and so on. These tables can be modified by the user, and since PostgreSQL bases its operation on these tables, this means that PostgreSQL can be extended by users. By comparison, conventional database systems can only be extended by changing hard-coded procedures in the source code or by loading modules specially written by the DBMS vendor.

How is PostgreSQL used?

Databases like PostgreSQL have more use cases than can be reasonably spoken about. After all, it's a foundational technology that by design, is as generic as possible - you don't want or need an opinionated database.

PostgreSQL can store structured and unstructured data in a single product. Unstructured data, found in audio, video, emails and social media postings, can be used to improve customer service, discover new product requirements, and find ways to prevent a customer from churning among countless other uses.

PostgreSQL also has superior online transaction processing capabilities (OLTP) and can be configured for automatic fail-over and full redundancy, making it suitable for financial institutions and manufacturers. As a highly capable analytical database it can be integrated effectively with mathematical software, such as Matlab and R. Due to PostgreSQL's replication capabilities, websites can easily be scaled out to as many database servers as you need.

Challenges of using PostgreSQL

Despite the benefits, there are challenges that enterprises shall be faced with when it comes to PostgreSQL adoption. PostgreSQL has one of the fastest-growing communities but unlike traditional database vendors, the PostgreSQL community does not have the luxury of a mature database ecosystem. In addition, PostgreSQL is often used in tandem with several different databases, such as Oracle or MongoDB and each database requires specialised expertise and hiring technical staff with relevant PostgreSQL skill set can be a challenge for enterprises. In addition to management tools for PostgreSQL, DevOps teams and database professionals need to be able to manage multiple databases from multiple vendors without having to change existing processes.

Second, as PostgreSQL is open-source, different IT development teams within an organisation may start using it organically. This can give rise to another challenge - no single point of knowledge for all instances of PostgreSQL in enterprise IT landscape. Further, there is redundancy and duplication of work, as different teams may be solving the same problem with it, independently.

How can start-ups and larger enterprises deal with these challenges? Let's look at a Canonical offering that aims to solve this.

Optimised PostgreSQL, managed for you

Managed PostgreSQL from Canonical is a trusted, secure, and scalable database service deployable on the cloud of your choice or on-prem. Never worry about maintenance operations or updates - we handle that for you. With Canonical's managing your PostgreSQL, you get the following benefits.

Summary

PostgreSQL offers a general-purpose database that is the backbone to many key technologies and apps we use each day. To optimise your deployment, improve quality and economics, speak to our PostgreSQL engineers today.

19 Jan 2021 8:54am GMT

Santiago Zarate: Quick and dirty ipmitool tutorial

Because I always forget

To reboot a SUPERMICRO server:

Just remember that the default user/password might still be ADMIN/ADMIN :)

ipmitool -I lanplus -H $HOST -U USER -P PASSWORD power cycle

To connect to the serial console

ipmitool -I lanplus -H $HOST -U USER -P PASSWORD sol activate

19 Jan 2021 12:00am GMT

06 Nov 2011

feedWhere is Ploum?

What happened during GSoC 2011?

I know I'm very late, but I really wanted to talk about this year Google Summer of Code.

For the third year in a row, I was a mentor. And this year I have a huge deception to share. I'm really sad. This week, I'v received the GSoC 2011 t-shirt. They sent me the wrong size. XXXL. I can use it as a sleeping bag with my girlfriend. I'm really disappointed.

GSOC 2011

Hopefully, GSoC is not only about receiving a t-shirt. It is also about mentoring a student.

Nearly two years ago, I started working on a complete refactoring of GTG. The code was a mess, with a lot of duplicate everywhere, with two bugs appearing while you were trying to solve one, etc.

I abstracted the structure we were using in several places and started to write a library to handle those "Acyclical Directed Graphs". As usual, it appeared that development was taking longer than expected. Weeks turned into months. Then, when it started to look good, I discovered that I forgot one critical point: thread-awareness. I felt hopeless.

Because I didn't had the motivation to do that heavy work, I proposed it as a Summer of Code project to a very motivated student: Izidor Matušov[1].

Words doesn't do any justice to the excellent work that Izidor did this summer. He's simply awesome. Some students are goods because they have previous experience. Izidor kicks asses. He learns so quickly, he's so assertive. The work was even harder than what we anticipated. But he managed to achieve everything, including feeding me with cookies at the Desktop Summit, where we met and had an awesome hacking week.

Lionel (Ploum) & Izidor at Desktop Summit

As much as I'm deceipted about the t-shirt, I'm delighted about the work achieved this summer. Izidor now knows GTG nearly as much as I do. He's taking initiatives, like organizing an online GTG hackfest on November 26th[2] and he's a bug-answering machine.

Dear Google, GNOME foundation and Lanedo[3], I would like to thank you. Thanks to your support:

  1. I received a worthless piece of clothes that travelled half of the world in order to clean my cat's dirtiness.
  2. GTG 0.2.9 should be released before the end of the year
  3. GTG gained a new co-maintainer
  4. I gained a new friend. And it probably worth everything else.

Congratulations, co-maintainer Izidor. And welcome to the community!

Notes

[1] Yes, I'm able to write his name correctly, thanks to my wonderful keyboard layout

[2] #GTG, on Gimpnet, during the whole day

[3] Lanedo paid for the travel, the accommodations and, as you can see on the picture, the clothes during the Desktop Summit

06 Nov 2011 6:23pm GMT

05 Nov 2011

feedWhere is Ploum?

The aristocratic desktop (part 4) : Kill The Double Click

Part 1 : Introduction
Part 2 : Home is Desktop
Part 3 : There's no tray icon in GNOME !
Part 4 : Kill The Double Click

When I started installing the best desktop possible for Marie and Jean, we were still in the GNOME 2.X era. GNOME 3 solved my previous concerns. No in the way I envisioned it, but solved them anyway. No more desktop icons, no more tray icons.

But now that I'm introducing Marie and Jean to GNOME 3, I still have some concerns. And one of that main concern is the infamous double-click!

Mouse click

Do you remember? Jean is a very brilliant mind, even though he never used a computer during his whole life. As a reasoning scientist, he was trying to find the logic behind my teaching.

During one of our first lesson, "Using the mouse", the conversation went like this:
- How do I know if I have to click or double click?
- Well, you double-click on icon and simple click on links and buttons.
- How do I know what is a button or an icon?
- …

Since that time, I've tried many times to find a logic behind single or double clicking. There is not. You have to learn it by experience. And it is totally, utterly pointless.

I also realized that a single click was something really hard for Jean. Achieving to click on a given point without moving the mouse is really hard for older people. Then, ask them to click twice, with a completely arbitrary speed, without moving the mouse, not to quickly, not to slowly. Impossible.

Marie, on her side, was double-clicking everywhere. And, surprisingly, it works most of the time.

So, why do we have double-click in some places? Because we want to be able to select an item without "activating" it. How often does it happen? Never for Jean. Very rarely for Marie.

To summarize, we are making the most frequent action very hard to nearly impossible in order to allow a very rare action?

I tried to disable completely the double-clicking in Nautilus.

Do you know what?

It works. Even for me. I had chronic pain in my hand and disabling double-click was a relief. I explained to Marie to never double-click anymore. She's still double-clicking from time to time but everything works even better than before. Jean was eventually able to launch a file from within Nautilus.

Selectiong multiple files Selection of one or multiple file with single mouse click

What about selection of files? I explained to Marie to draw a square with the mouse. And, yes, she found that absolutely intuitive. The only drawback I found so far was the inconsistency with lists, where double-clicking is still required. Marie called me one day because she tried to play a specific song in Rhythmbox. It wasn't working. I realize that she had to double-click on the song. "But you told me to never double click anymore!". Sorry Marie.

I'm myself incredibly frustrated by any system that requires double-click. Why do we still have double-click by default in GNOME3?


Part 1 : Introduction
Part 2 : Home is Desktop
Part 3 : There's no tray icon in GNOME !
Part 4 : Kill The Double Click


Picture by Dave Dugdale

05 Nov 2011 12:17pm GMT

28 Oct 2011

feedWhere is Ploum?

J'irai pisser sur votre moquette

Si vous deviez me décrire en deux mots, nul doute que fourbe et profiteur vous viendraient spontanément à la bouche. Paresseux, parasite et inutile suivraient de près. Et j'en suis fier. J'en ai même fait mon mode de vie.

Ma technique est simple mais éprouvée. Je croise un inconnu dans la rue à l'air affable. Tenez, prenez ce jeune homme à l'allure dynamique. Il s'appelle Jean, c'est ma prochaine victime. Il ne se doute encore de rien mais j'irai dormir dans le lit de sa femme tout en vidant son frigo.

Au premier abord, je fais le numéro du sympa-sociable, les circonstances m'ont conduit dans la rue, où j'ère sans but précis, mais je ne me plains pas, je ne quémande rien, au contraire, je refuse tout geste de pitié trop ostentatoire. J'ai ma fierté.

Lorsque Jean se propose de m'emmener manger à la maison, juste pour la soirée, je fais d'abord mine de ne pas être intéressé. Mais mes yeux acquiescent et Jean, en rigolant, insiste, me forçant presqu'à le suivre. Inutile de vous dire que c'est ce que j'attendais mais la victime doit croire qu'elle a l'initiative, c'est primordial.

Martine, la femme de Jean, n'est que moyennement contente de cet imprévu. Qu'à cela ne tienne, je fais mon charmeur, je séduis tout en ayant l'air de ne pas vouloir déranger. Je fais également un peu le pitre pour la dérider.

Et ça marche. Avant la fin de la soirée, elle discutera avec moi plus qu'avec Jean lui-même, ce dernier étant parfaitement inconscient du destin de proie que je lui réserve. De manière indirecte, je fais comprendre que je n'ai nul part où aller. Jean et Martine n'ont pas le cœur de me renvoyer seul dans le froid de la nuit. Ils se proposent donc de m'héberger, juste pour une nuit. Tandis que je m'installe confortablement sur le sofa, j'entends Martine descendre l'escalier. Elle est en déshabillé, prête à aller au lit.

- « Bonne nuit ! » me lance-t-elle avec un sourire innocent avant de remonter dare-dare dans sa chambre.

Je ricane. Je n'ai même pas eu besoin de répondre. Une seule soirée me suffit. Homme ou femme, nul ne me résiste. Je suis comme ça moi.

Bien entendu, le « seulement pour une nuit » se prolongera. Je commencerai doucement à faire comprendre mes goûts précis, envoyant Jean au supermarché afin de m'acheter ce que je souhaite. Lorsqu'elle rentre du travail, Martine a à peine un regard pour Jean. Elle se rue à l'intérieur pour voir comment je vais. Pendant ce temps-là, je me prélasse sur le canapé, je me balade un peu. Avec mon air faussement négligent, j'ai pris soin de casser quelques bibelots auxquels ils tenaient beaucoup, par pure cruauté.

Lorsque Jean partit quelques jours dans sa famille à l'étranger, je n'hésitai pas: je me glissai une nuit dans le lit de Martine, sans même lui demander, sans même m'annoncer. Elle prit un air faussement surpris mais je sais qu'elle n'attendait que cela. Elles sont toutes les mêmes. Jean nous a surpris en rentrant plus tôt. Cela ne lui a pas plu. Il m'a dit qu'il m'avait sorti de la rue, qu'il n'acceptait pas cela.

Par méchanceté, j'ai répondu en déféquant sur la moquette du salon. Il a pu tout nettoyer. Il n'était vraiment pas content mais Martine a fini par le convaincre de me garder et d'exercer le moindre de mes désirs.

Il faut dire qu'ils sont vraiment bien mes deux esclaves. Je dors dans leur lit, ils me nourrissent, nettoient sans que je n'aie besoin de faire attention à rien. Quoi que je fasse, ils me regardent avec un air attendri et me trouvent adorable. Même au milieu de la nuit, il suffit que je me mette à miauler pour qu'ils s'enquièrent immédiatement de mes besoins.

Des esclaves aussi dociles, c'est rare. Je vais les garder encore quelques temps.

28 Oct 2011 4:59pm GMT