Feedback from PGDay.EU - the speakers

The next issue of my "pie-chart-overflow blog posts about PGDay feedback" is about our speakers. The speakers are, if that's not obvious, the reason that people come to the conference. Having good speakers is an absolute requirement if we want to keep up the quality of the conference. Other things like venue and price are certainly important, but nothing compares to the actual content of the conference - which is provided by our speakers.

I'm very happy to say that we seem to have manage to keep the very high numbers for Speaker Quality that we had from last year (differing less than 3%25 which is well within the margin of error). The same goes for the scores our speakers got on their knowledge of the topic - indicating that we've managed to attract some of the most skilled speakers in the world. Which is not surprising given that in many cases, we the person speaking about a feature is actually the guy who wrote it. What is more surprising is that these same people are rated as very good speaker - which we all know isn't always true about your stereotypical developer.

Just like last year, we're not going to post the complete list of speaker ratings, given that they are easy to read wrong. But here is a list of our top speakers, excluding any that had less than 5 ratings. Any speakers who have fewer than 10 should be considered a very uncertain number, and I've again included the standard deviation to determine the uncertainty. We had a lot more speakers this year, so I have only included those scoring 4 or above this time around. Each speaker has received his own detailed score, of course.

Place | Speaker | Quality Score | Standard deviation | Number of votes 1 | Dimitri Fontaine | 4.8 | 0.5 | 8 2 | Mason Sharp | 4.7 | 0.9 | 11 2 | Magnus Hagander | 4.7 | 0.7 | 29 4 | Simon Riggs | 4.6 | 0.7 | 52 4 | Simon Phipps | 4.6 | 0.9 | 45 6 | Andreas Scherbaum | 4.5 | 0.7 | 34 6 | Ed Boyajian | 4.5 | 1.1 | 33 8 | Bruce Momjian | 4.4 | 0.9 | 54 8 | Gianni Ciolli | 4.4 | 0.8 | 38 8 | Tim Bunce | 4.4 | 1.0 | 10 11 | Jan Aleman | 4.2 | 1.0 | 11 12 | Tim Child | 4.1 | 0.8 | 9 12 | Michael Meskes | 4.1 | 1.2 | 10 14 | Bernd Helmle | 4.0 | 0.6 | 6 14 | Heikki Linnakangas | 4.0 | 0.8 | 30 14 | Linas Virbalas | 4.0 | 0.9 | 10

[HTML_REMOVED] The list based on Speaker Knowledge looks slightly different, but not very much. Given that our speaker knowledge has been rated even higher than speaker quality, I've only included those who scored 4.6 or higher (which is a fantastically high cutoff)

Place | Speaker | Knowledge Score | Standard deviation | Number of votes 1 | Tim Child | 5 | 0 | 9 2 | Joe Conway | 4.9 | 0.3 | 10 3 | Simon Riggs | 4.8 | 0.7 | 52 3 | Linas Virbalas | 4.8 | 0.4 | 9 3 | Magnus Hagander | 4.8 | 0.8 | 29 3 | Dimitri Fontaine | 4.8 | 0.5 | 8 7 | Andreas Scherbaum | 4.7 | 0.8 | 34 7 | Bruce Momjian | 4.7 | 1.0 | 53 9 | Mason Sharp | 4.6 | 1.2 | 11 9 | Heikki Linnakangas | 4.6 | 0.8 | 30 9 | Simon Phipps | 4.6 | 1.0 | 45 9 | Gianni Ciolli | 4.6 | 0.8 | 38 9 | Tim Bunce | 4.6 | 1.3 | 10 9 | David Fetter | 4.6 | 0.6 | 16

A great big thanks to all our speakers - you did a fantastic job.

We will need to work hard to keep up our recruiting of speakers for next years. If you were considering but decided not to submit a talk for some reason - please let us know why, so we can improve! Or if you have any ideas in general on our processes around this. For example, we had no female speakers at all this year - we know you're out there, and we certainly want you there, so what do we need to change to make this more interesting for you as a potential speaker? The same goes for other groups that we were missing of course: now is the time to let us know so we have the time to change things before next year!

Feedback from PGDay.EU - the contents

This blog seems to be turning into a PGDay blog rather than a general PostgreSQL blog. But I promise I'll get back to some more technical content soon - or at least that I'll try.

A couple of days ago we closed the feedback system from PGDay.EU 2010, and have been busy tallying the result. It turns out that my constant nagging on people to please fill out the feedback worked - we got a lot more feedback this year than last year. That also means there's a lot more work in going through mainly all the freetext comments - that's the price I have to pay, I guess. In total we had around 60 people who left "full conference feedback", which is almost double from last year. It's still only just over 25%25 of the attendees, so it could certainly be even better yet. We also had 86 people who left session feedback (this is around 40%25 and a much better number of course) for a total of 570 session feedback entries.

So what did the feedback say - time for some pie charts! We've actually seen a slight decrease in the ratings for topic importance. This may well be because we've broadened the topics more. We're still seeing very good grades for content quality, which reinforces my feeling that our speakers deliver very valuable content to the attendees, and that the conference is well worth attending. (As a note to readers - I've had several people point out to me that german people are used to rating 1 being the highest and 5 being the lowest, so there may be some skewing in the voting because of this. Even though the pages very clearly stated that 5 is the highest, this is something we need to make even more clear for next year)

We spent a lot of time trying to put together the puzzle that is the schedule for so many talks over so short time. It turns out that we did a good job in general, but there was a large amount of overlap where people wanted to go to many talks at the same time. We also received a lot of comments in the freetext fields about this, and this is definitely something that we will consider for next year. It would probably have been better content-wise to have three tracks spread over three days (maybe not entirely complete) rather than four tracks over two days, but that would also have increased many of the costs with 33%25 which is a lot of money...

Of course, the "Hallway track" is a very important part of any conference like this, and this year we collected specific feedback on this side. I'm very happy to see that more than two thirds of our attendees rated the learning part of the hallway track as 4 or 5, and well over half found it a good way to connect with other people in the community!

If these numbers don't make you interested in next years PostgreSQL Conference Europe then, really, you're reading them wrong...

That's enough pie-charts for one post. I will follow this up with more feedback summary on our speakers and on our venue once it's ready. registration deadline extended

The registration deadline for has been extended. Instead of ending today, the new deadline is Saturday, December 4, 17:00 CET. There are, however, a few restrictions with this extension:

  • After today, November 26th at midnight, we will only be able to process creditcard/paypal payments, or cash payments at the registration desk.
  • After 17:00 CET today, November 26, the pre-paid discounted internet access for people not staying at the hotel will no longer be available. Internet access is still included in your room rate if you book with the PGEUROPE group rate.

Once this second deadline expires on the December 4th, you are still welcome to attend the conference - but in this case, you have to pay the higher price for a pay at the door registration. Even if you choose this, we do appreciate if you register online first (choosing that rate), so we can prepare a badge and conference pack for you.

If you have any further questions, please contact us at

PGDay.EU - where's your country?

Initial numbers from our registration database for PGDay.EU 2010 is showing that we are expanding our international reach more than last year. In 2009, 60%25 of the attendees were from France, which is where the conference was held. This year the number of attendees from Germany is "down" to about 50%25, meaning we have more people from other countries. The total number of countries is down one though - we have no registration from Nicaragua this year! Even our attendance from the US is up to three more people.

Pardon my horrible chart, but here is the current spread of attendees. Where does your country stack up? If it's not Germany, then it's not high enough - time to suggest/encourage/force/trick your friends and colleagues to register and attend! (And if it's Germany - hey, can you really let the French get to 60%25 last year and not beat them this year?)

Registration for PGDay.EU 2010 closes soon! Don't miss out on the biggest PostgreSQL event in Europe this year, and all the great presentations!

Make your picks - PGDay.EU 2010

PGDay Europe 2010 is drawing closer - only two weeks until kickoff! Some of the training is filled up, but we still have space for some more people on the general conference (and some of the training sessions). It's not too late - go register!

I'll be spending much of the time working with the conference administration, hopefully making things flow. But with a schedule like this, there are some sessions that I'm definitely not going to miss:

  • The keynote, of course. Simon Phipps is a well known and very experienced Open Source speaker and worker. He'll be talking about "Back to the Future of Open Source", and it will be very interesting to hear his perspective on this, having been on the inside of for example Sun.
  • Play chess against PostgreSQL (and get beaten) with Gianni Colli. You just need to read the title, of course I have to see it :-) Unfortunately it's up against PgOpenCL, but that's what happens when you have so many good talks.
  • I think I can skip out of Simon Riggs talk about replication - I need to have my class for Wednesday ready before this anyway. But I highly recommend it to anybody who is planning to deploy the 9.0 replication features.
  • That afternoon I'll be busy with the conference, and won't get to go to any of the talks... I'll definitely miss the Concurrency talk, the clustering and the psycopg one.
  • Tuesday, I can't quite decide between Developing PostgreSQL performance or Graph Constraints, and Why You Care. But we put two such great talks early in the morning to make sure everybody gets up!
  • Next I'd go to Stefans talk about benchmarking, but it's in German, so I think I'm better off not doing that. It'll be the case-study of the large deployment that Bull did for the French social services instead.
  • Before lunch, I think it'll be Postgres-XC. I've been to a lot of conferences now where Mason has held a talk about this, and never actually managed to see one...
  • After lunch, I'm again stuck at doing work (sheesh). If you haven't seen it already, I recommend Bruce's MVCC talk. There are other good ones as well, of course, but Bruce does a very good "deep introduction" to PostgreSQL's implementation of MVCC.
  • Obviously there's no skipping out on the closing keynote. Ed usually does a good job - I expect no less this time.

With this much great content, it's hard to choose - but those are my choices for PGDay. (I of course reserve the right to change my mind, depending on how late the speaker left from the party the day before)

What are yours?

And if you haven't registered yet, you still have a few more days. Don't miss your chance to attend the biggest PostgreSQL event in Europe this year! Registering is easy and quick - not to mention cheap!

Back to conferencing - PGWest

Today is the first day of PG-West, also known as JDCon-west. After having about a week off to visit places and visit friends, I'm now back up in San Francisco for this conference, which will cover most of this week. It's a bigger conference than JDCon has been before - in most measures. It as more sessions than ever before - but you have to wonder who thought it was a good idea to have five parallel sessions. That's almost a guarantee that there will be more than one session you really want to go do. I'd rather have seen it in fewer tracks and spread over more time.

It's also bigger in attendees than before. Last I heard it was at 203 or something like that - just over 200. That means that for the first time, JDCon is actually larger than a PGDay.EU (that had just over 190 last year) - I'm sure being in a great location in central San Francisco helps with that, along with the fact that the economy is in a better place now than a year ago. We're still in the lead over time (we were well over 200 a couple of years back), but we're also both well beaten by the Brazilians. It' sets a good target for us to work towards!

The set of sessions looks really good, but as usual the hallway track is the one where much of the really good things happen. I missed this mornings tutorial sessions completely due to very interesting discussions outside. Hopefully the slides and notes and/or video will be available to look over once we're done. If you're tracking this from away, the twitter stream has some interesting comments - and will hopefully have more!

Speaking of conferences - if you haven't already, now's a good time to register for Particularly if you are planning to attend one of the training sessions - at least one of the sessions is already more than half sold out!

PGDay Europe 2010 Registration Open

It's finally time - we've opened up for registrations for PGDay Europe 2010.

We are not finished with the schedule yet, so if you are looking for a specific talk, you'll have to wait a while longer. Work is in progress though - we've already notified some of our speakers that they are approved. However, if you submitted a talk and have not heard from us yet, it's not yet time to panic. The reason we haven't published a schedule yet is that we're working on ways to include more talks!

So why would you want to go register now, even though the schedule isn't posted yet? Well, first of all, the schedule is looking like it'll be at least as good as last year. We have several well known good speakers from the community showing up again, and also some fresh faces with interesting topics!

But more importantly, this year, we've added training for the first time. Training will run on the wednesday (the main conference being monday and tuesday). This training is limited availability (25 seats per session), and extra cost. You pay this at registration. And the seats are handed out on a first come/first serve basis. So if you want to attend the training, now is the time to register! The training schedule is final, so be sure not to pick two training sessions that run at the same time.

The conference this year will be held at the Millennium Hotel in Stuttgart. We do recommend that you reserve a room with that hotel, as we have a group rate there, and it's conveniently located (hint: no need to go outside to get from A to B). But using this hotel is not mandatory - you can book your room anywhere you like. However, it should be noted that wireless internet is only included if you booked a room using our group rate. If you don't, you can pre-purchase the access when you register, or you can solve it yourself for example using 3G data. We will not have the ability to provide or sell you wireless access unless you pre-purchase it!

With all that said, head off and register!

Monitoring streaming replication lag

Once you've set up the great new Streaming Replication with Hot Standby in PostgreSQL 9.0, you need to somehow monitor it. I've created a simple Munin plugin to graph the lag between the master and the slave, and also the lag between receiving and applying on the slave. It's available on my github page, and will likely also be included in the next Munin version. If you are using SR and Munin (or just SR and want to graph it), please try it out and let me know if there are issues with it - it could certainly do with some more testing.

PostgreSQL - now on git!

So it finally happened. The official PostgreSQL master source tree is now managed in git, instead of cvs. This means, amongst other things, that the worlds most advanced open source database now has a version control system with.. eh. atomic commits!

Like the first run, this one had some issues with it, but it was smaller and resolved in time not to have to roll back. This time, it turned out that the cvs version that ships in Debian GNU/Linux comes with patches that change the default date format to the ISO standard. But since one of our main requirements on the conversion was to be able to faithfully represent the old versions of the code, this broke every single file - since we used CVS keyword expansion in the old tree. Once we found this, it was a simple case of adding the DateFormat=old parameter to the CVS config file and re-run the whole conversion - which took several hours.

A lot of work went into making the repository conversion correct. Some of this was due to issues in the toolchain used - many thanks to Michael Haggerty and Max Bowsher for getting those fixed and explaining some of the behaviors of the software for us. In the end, a number of things needed to be changed in our existing CVS repository to make it migrate properly. Tom Lane provided a big patch to apply to the CVS repository itself prior to the conversion that cleaned most of those up - you can find a copy of it my github page if you're interested.

With this patch applied, we managed a conversion that was very close to the original repository. I personally think this is only because the PostgreSQL project has been very careful about how it deals with it's CVS repository - using it in a fairly simple way. And even with that, we had a number of issues - such as tags moved "after the fact", and branches created off partial checkouts. A fair number of the issues were simply because CVS doesn't have ways to represent everything in a reasonable way, such as issues when a file was deleted, re-added, deleted again, and mix this over different branches.

Git obviously deals with this better, and hopefully we'll have no such issues creeping into the new repository. However, the PostgreSQL project will be sticking with our "conservative approach" to source control - at least for the time being. For this reason, we are restricting what committers can use within git. We still allow any developers (and committers) to use whatever parts of git they want as they develop, but for commits going into the main tree, we are making a number of restrictions:

  • We will not allow merge commits. The PostgreSQL project doesn't follow the "git workflow" - we generally develop our patches on the master branch, and then back-patch to released stable branches for important bugs. We will continue doing this as separate commits and not using merges, thus keeping history linear.
  • We will not use the author field in git to tag it with the patches original author (even in the few cases when the patch is actually authored by a single person). Instead, we will require that author and committer are always set to the same thing, and we will then credit the author(s) (along with the reviewer(s)) in the commit message, just like we've done before.
  • As a follow-on to that requirement, we will require that all committers are the ones registered with the project, using the same name and address on all commits. So even if a patch is developed on a topic branch on say github, it will get collapsed into a single commit (or maybe a couple, depending on size) tagged with the committers name on that.

There has been a lot of discussion around this, and this is how the PostgreSQL project has worked and wants to continue working. We may change this sometime in the future, but not now - we are only changing the tool, and not the workflow.

To enforce these requirements, I've developed a policy hook for our git server that makes sure we don't make the mistake. It's up on my github page, along with the script we use to generate commit mails to the pgsql-committers list that look just the way we want them to.

What does this mean for you as a PostgreSQL user? Really, nothing at all.

What does this mean for you as a PostgreSQL patch developer? Not much. If you did your work off the cvs-to-git mirror, you need to do a new clone. This repository is converted from scratch, so the old one is not valid anymore. We still encourage you to use for example github if you want to do your development there, but the patch submission process remains the same - send a context style diff to the pgsql-hackers mailinglist.

What does this mean for you as a buildfarm-animal maintainer? You need to reconfigure it to use git. I expect Andrew to post instructions on exactly what to do, and keep track of who hasn't done it ;)

Thanks and Well done to all the people involved in making this happen!

A busy week for PostgreSQL - hello 9.0!

In case you missed it (I'm certainly not the first on Planet PostgreSQL to blog about this, but there are supposedly other aggregators), PostgreSQL 9.0 has been released. Comes with spiffy things like Streaming Replication, Hot Standby and Exclusion Constraints! If you aren't up to speed on all the news already, go check out the release notes.

Second, I yesterday committed Thom Browns changes to the stylesheets for the documentation. So not only do you get the documentation for the new version, it also looks a lot better than the old one - nicer formatting for tables and highlighting examples and code in a better way. This is also changed in the old version of the docs.

Finally, tonight we start the second attempt to move the authoritative PostgreSQL source tree to git. It didn't end well last time and we reverted back to cvs, but given the large amount of work put into it by many people, I have much higher hopes this time. Stay tuned...


I speak at and organize conferences around Open Source in general and PostgreSQL in particular.



PGConf.EU 2019
Oct 15-18, 2019
Milan, Italy
Postgres Open 2019
Sep 11-13, 2019
Orlando, FL, USA
Postgres London 2019
Jul 2-3, 2019
London, UK
PGCon 2019
May 27-31, 2019
Ottawa, Canada
PGDay.IT 2019
May 17, 2019
Bologna, Italy
More past conferences