Weekly tweet digest for 2010-07-18

PDXPUG Day 2010: 9.0 and all sorts of good stuff

I’m nearly ready for PDXPUG Day 2010.

We’ve got some fun talks lined up from leaders in the Postgres community in town for OSCON. It’s free to attend. We’ll at the Oregon Convention Center, room D131.

Stop by sometime during the day if you’re in town!

Here’s our schedule:

10am: What’s new in 9.0 – Selena Deckelmann
11am: ORMs and Their Discontents – Christophe Pettus
1:30pm: Mining Your Logs For Fun and Profit – Josh Berkus
2:30pm: PORTAL – Dan Colish
3:30pm: An Introduction to Managing and Troubleshooting PostgreSQL on Windows – Tim Bruce
4:30pm: PostgreSQL in Brazilian Army and Air Force – Luis Dosso

6pm-10pm: Party at the Gotham Tavern!

twittering on 2010-07-15

  • Plan for bike riding with the ladies friday: epic win. #
  • Also, my dance card is filling up for OSCON. Looking forward to seeing everyone! #
  • perl6 -e "say 'hello world'" #pdxpm #
  • OH: "I got no STD!" "I got my tests back!" #pdxpm #
  • OH: It depends how greek you are. #muormoo #
  • OH: "Perl6 is smarter than I am." "And that is why it has taken so long." #pdxpm #

Foocamp 2010: lovely, expectant, reflective

This has been sitting in my edit queue for too long… here goes.

So, I was invited to Foocamp this year. Back in February, I attended KiwiFoo at the invitation of Nat Torkington. I realize now (sorry, Nat!) that I never blogged about going there. I have some rough notes around that I may try to edit down.

I’ll avoid any direct comparisons for a moment, and just talk about what it was like to dive into a slice of Silicon Valley, dislocated into the countryside for a weekend.

When I arrived, I felt immediately at home, welcomed and appreciated. Sara Winge was so helpful and easy-going about the Tesla Coil Josh brought. (Thanks for the ride, Josh!) I spent a lot of evening time educating people about avoiding touching the sparks (it may be a pretty toy, but it is in fact a dangerous one!) and also playing around with a metal glove that was rigged up so you could get a bit closer in to the coil.

I spent a couple delightful hours considering claude glass with Roberta Cairney. Over and over, I absorbed the positive energy tumbling out of Sumana. Once again, I spoke with Kiwis whose humor and affectionate swearing reminded me of home.

I held one session – about forgetting and the ethics of shifting our culture to assume everything may be on your permanent record, and the ways in which people try to opt out or game the system. I was surprised and overwhelmed by the people who attended. Rita King, Scott Berkun, Biella Coleman and danah boyd were all part of the discussion and I was able to talk about ideas I’ve had tumbling around in my head for years. I believe sysadmins/devops must have conversations about the ethics of the default choices made by developers around configuration and long-term management of log data. People asked provocative questions, and we had a real debate about the ethics. It was a wonderful experience and I came up with at least one good idea that I hope Jesse Robbins and I are going to act on together.

I also ran into several people who are just starting to work on user group and community issues in their geographic areas. Seattle came up over and over – and I’m looking forward to helping Ben Huh and the open gov folks who want to do grassroots organizing in their tech communities. I also met some amazing women there, and hope that we’re able to continue our discussions about business and tech in the future.

I camped, and was in a tent under the stars, and early morning fog. I enjoyed running into a fellow PostgreSQL community member, Paul Ramsey, among the early risers.

Apart from the immediate things to collaborate on, and an incredibly long list of new ideas and connection points, I came away inspired and mentally refreshed. I relished the relative lack of device obsession. The people that I wanted to have conversations with tended to have put their devices away for a few hours, and were focusing on the people in front of them.

The Ignite talks were my favorite talks. Jake Applebaum‘s meditation on wikileaks was particularly inspiring, reminding me to seek out opportunities to change the world for the better.

Q&A about Hot Standby

Updated!: See below.

Here are some questions that came up from trying to use the current PostgreSQL hot standby documentation:

Q: If you set hot_standby = off after having it on, what happens?

A: This change requires a database restart on the hot standby (or replica) server. The database goes into “warm standby” mode, and you can no longer issue queries against it. You can change this right back by setting the parameter to ‘on’ and restarting again.

Q: Can you use hot standby with only a single schema or database?

A: No. Hot Standby is all-or-nothing for a particular PostgreSQL database cluster. A cluster is made up of all the databases that live in a particular $PGDATA instance, and Hot Standby is currently not capable of distinguishing between changes occurring on different particular databases or schemas.

Q: Is the process for setting up hot standby any different for empty databases vs. populated databases?

A: No. The setup process is the same – you must create a base backup.

Q: How do I bring my hot standby out of standby mode?

A: If you’re using something like the following in your recovery.conf file:

restore_command = 'cp xxxx'
standby_mode = 'on'

Change: standby_mode = 'off' and restart your hot standby postgresql instance.

Q: Where did my recovery.conf file go? (after your database came out of warm/hot standby)

A: PostgreSQL automatically changes the name of the file to recovery.done when recovery completes. This helps prevent accidents.

Q: What happens if my archive_timeout = 60 (which creates a 16mb file every minute) and I flood the database with so much activity that my standby falls behind?

A: This is possible, and you may be interested in trying Streaming Replication. However, for the majority of users, a delay in restoring data is acceptable (and possibly desirable). Eventually the standby server will catch up. You can monitor how delayed the server is using functions like txid_current_snapshot().

Q: Are schema changes (like CREATE TABLE or ALTER TABLE) replicated to the standby?

A: Yes! All changes to the database cluster are copied to the standby. This includes any DDL operations, new rows, the effects of autovacuum — any change to the data store on the master is copied to the standby.