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Andreas 'ads' Scherbaum

At FOSDEM someone asked how long 64 bit Transaction-IDs will last.

To refresh: PostgreSQL is currently using 32 bits for the TXID, and is good for around 4 billion transactions:

fosdem=# SELECT 2^32;
  ?column?  
------------
 4294967296
(1 row)

That will not last very long if you have a busy database, doing many writes over the day. MVCC keeps the new and old versions of a row in the table, and the TXID will increase with every transaction. At some point the 4 billion transactions are reached, the TXID will overrun, and start again at the beginning. The way transactions are working in PostgreSQL, suddenly all data in your database will become invisible. No one wants that!

To limit this problem, PostgreSQL has a number mechanism in place:

• PostgreSQL splits transaction ids into half: 2 billion in the past are visible, 2 billion in the future are not visible - all visible rows must live in the 2 billion in the past, at all times.
• Old, deleted row versions are enevtually removed by VACUUM (or Autovacuum), the XID is no longer used.
• Old row versions, which are still live, are marked as "freezed" in a table, and assigned a special XID - the previously used XID is no longer needed. The problem here is that every single table in every database must be Vacuumed before the 2 billion threshold is reached.
• PostgreSQL uses lazy XIDs, where a "real" transaction id is only assigned if the transaction changes something on disk - if a transaction is read only, and does not change anything, no transaction id is consumed.

The PostgreSQL Project was assigned a devroom at FOSDEM again this year. We got a room with approx. 200 seats, and as usual every last seat was taken for many of the talks. This requires that we manage the room very effectively and carefully, both to avoid that people walk in and out at all times and disturb the speaker, but also in order to keep the exits free at all times.

For a speaker it is quite disturbing if the door in the back opens, someone walks in, down all the way to the front, tries to find a seat, walk around to the other side, maybe leaves again, or just stays somewhere and blocks the exit. The worst case is when there is a free seat somewhere in the middle of a row, and everybody has to get up to let the new attendee in.

The FOSDEM team requires that we keep the exits free, in case the room needs to be evacuated. If people are staying on the steps along the wall, it is not possible to clear the room effectively and quickly.

For more than 10 years, the PostgreSQL Project is present at FOSDEM. We also organize a separate PostgreSQL Day on Friday.

This blog post presents useful information about both the PGDay and the booth and devroom at FOSDEM.

Andreas 'ads' Scherbaum

FOSDEM 2017 is over, and hopefully everyone is back home. Time for a short review.

Once again, PostgreSQL ran a pre-conference to FOSDEM, called PGDay. One day just filled with awesome PostgreSQL talks, and meeting community members.

Many speakers uploaded or linked their talks to the PostgreSQL Wiki. If the slides for a talk are missing, please contact the speaker and ask them to upload or link the slides. (For the record, my slides are here)

The FOSDEM video team already uploaded the recordings, and the PostgreSQL Volunteers reviewed every single video. Find them here. Devrim also did short recordings of most of the talks, and posted them on Twitter.

The Hacker Public Radio did interviews with many projects, including PostgreSQL. Find the interview here.

The PostgreSQL Project had a Devroom on Sunday. The schedule is part of the regular PGDay/FOSDEM schedule. And of course we managed to fill the room to the last seat, standing room only. If only people would obey the "Room is full" sign on the door ;-)

We also had a booth (pic 2, pic 3) in the main building, where you can talk with community members about anything around PostgreSQL. Also we had some nice merchandise. Matching the bad weather, the umbrellas went very well. We promise to have more next year.

Last but not least, Slonik visited FOSDEM. Here is just a short selection of pictures.

Hope to see you all next year!

P.S.: The next PostgreSQL Europe Conference will be in Warsaw, in October. Details can be found here.

I had the opportunity to talk about the many datatypes in PostgreSQL, in the PostgreSQL Devroom at FOSDEM 2017. It's quite interesting how many people only use the basic data types and don't know the broad range of types which PostgreSQL is offering.

My slides are available here: *click*

Like the past 10 or so years, the PostgreSQL Project is present at FOSDEM 2017. We also organize a separate PostgreSQL Day on Friday.

This blog post presents vital information about both the PGDay and the booth and devroom at FOSDEM.

Andreas 'ads' Scherbaum

FOSDEM PGDay is a one day conference that will be held ahead of FOSDEM in Brussels, Belgium, on Jan 29th, 2016. This will be a one-day focused PostgreSQL event, with a single track of talks. Registration is required to attend, the registration will open soon. Since we have a limited number of seats available for this event, we urge everybody to register as soon as possible once open.

PostgreSQL Europe will also have our regular devroom at FOSDEM on Sunday the 31st, which will be held at the main FOSDEM venue at ULB. This day will, of course, continue to be free of charge and open to all FOSDEM entrants. No registration is required to attend this day.

For full details about the conference, venue and hotel, see http://fosdem2016.pgconf.eu/.

The call for papers is now open for both these events. We are looking for talks to fill both these days with content for both insiders and new users. Please see http://fosdem2016.pgconf.eu/callforpapers/ for details and submission information.

The deadline for submissions is December 7th, 2015, but we may as usual pre-approve some talks, so get your submissions in soon!

We will provide a special rate with the Brussels Marriott Hotel. For details, see http://fosdem2016.pgconf.eu/venue/.

Andreas 'ads' Scherbaum

FOSDEM PGDay is a one day conference that will be held ahead of FOSDEM in Brussels, Belgium, on Jan 30th, 2015. This will be a one-day focused PostgreSQL event, with a single track of talks. This conference day will be for-charge and cost 50€, and will be held at the Brussels Marriott Hotel. Registration is required to attend, the registration is open. Since we have a limited number of seats available for this event, we urge everybody to register as soon as possible once open.

PostgreSQL Europe will also have our regular devroom at FOSDEM on Saturday the 31st, which will be held at the main FOSDEM venue at ULB. This day will, of course, continue to be free of charge and open to all FOSDEM entrants. No registration is required to attend this day.

For full details about the conference, venue and hotel, see http://fosdem2015.pgconf.eu/.

The call for papers is now open for both these events. We are looking for talks to fill both these days with content for both insiders and new users. Please see http://fosdem2015.pgconf.eu/callforpapers/ for details and submission information.

The deadline for submissions is November 24th, 2014, but we may as usual pre-approve some talks, so get your submissions in soon!

We also have negotiated rate with the Brussels Marriott Hotel. For details, see http://fosdem2015.pgconf.eu/venue/.