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Speaker Interview: Jean-Christophe Arnu

Dig the WAL   Tuesday 13:30   Berlin B

Twitter: @jcarnu LinkedIn: jean-christophe-arnu Company website:

Could you briefly introduce yourself?

Hi, my name is Jean-Christophe. I live in the south of France.

I'm a PostgreSQL enthusiast since 1997 when I started using PostgreSQL at the end of my university. At that time, Postgres95 was just renamed PostgreSQL.

In my professional life, I used various RDBMS but PostgreSQL was still a first choice. I get more and more experience in administration whereas mainly involved into development tasks. I've used PostgreSQL in many use-cases but the most representative is a flood disaster warning system to prevent life and material issues on a wide area.

Today I work for Loxodata, The French PostgreSQL consulting company.

I'm still developing tools for our customers and contribute to the PostgreSQL project.

How do you engage with the PostgreSQL Community?

I started to chat (on IRC) with the community around 2000/2001. With some other French people we decided to create PostgreSQLFr, a non-profit organization for French-speaking PostgreSQL users in 2004/2005.

In 2008, I organized the first with PostgreSQLFr in Toulouse (France). And this year I was at the 10th anniversary edition of this event as a speaker! I ran trainings for RMLL years ago. I also attended my first PGDay Europe in Prato (Italy) and then it became PostgreSQL Europe.

Recently I was speaker in Toulouse PostgreSQL users Meetup. I'm also involved in translations or proofreading French translations for press releases.

As you can see, my contribution is small, but I hope I could give more time and produce more with time!

Have you enjoyed previous or FOSDEM conferences, either as attendee or as speaker?

Oh yes I have!

Each I was attending was awesome. I was in Prato, Stuttgart, Amsterdam. This year I was also for the first time in FOSDEM conference. And this 2019 edition is my first time as a trainer! I can't wait meeting all the people I've already met the previous years and new PostgreSQL enthusiast people!

What will your training be about, exactly? Why this topic?

Well, it's all about WAL files. You know, the famous files in pg_wal directory (you had previously in pg_xlog) with strange hex names. I always wondered what was actually inside these files, what kind of information could be found in them, how they could be used? I mean, how can a crashed cluster be recovered using the information stored in these files? I also wanted to know the tools that can be used to perform different tasks with WAL files. These were real questions I had as a DBA and as a developer. Therefore, if I had these questions, others should have too. That’s why I thought I should share my discoveries. Isn’t it what opensource is all about? Sharing knowledge. All these questions will be answered in that training (well partially because I surely couldn’t imagine all the use cases one can think of). We've built special virtual machine image in order to create specific use cases for that training, this is a hands-on training!

What is the audience for your talk?

Any DBA or DevOps who already has a previous experience in Point In Time Recovery and PostgreSQL Administration.

What existing knowledge should the attendee have?

Well, medium knowledges are prerequisites:

  • Knowing the Debian PostgreSQL wrappers for cluster management
  • Using psql (always do!)
  • Having first experience in PITR
  • Be curious

What is the one feature in PostgreSQL 11 which you like most?

Definitively all the features around performance enhancements like parallelism and JIT.

Which other talk at this year’s conference would you like to see?

There are lots of interesting talks so it's difficult to choose one in particular. My favourite ones: