David Fetter's blog

Git down!

nospam@example.com (David Fetter) — Tue, 08 Jan 2013 18:19:09 +0200

Here's how I've arranged my browser to look at the official PostgreSQL git repository. I just put the hash in and go.
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How do you use PostgreSQL?

nospam@example.com (David Fetter) — Thu, 01 Nov 2012 05:15:00 +0200

My company's commissioned a survey. We made it PostgreSQL-specific and will be sharing the raw data along with the processed results.

http://svy.mk/TuMZYT

Give me your tired, your poor...

nospam@example.com (David Fetter) — Tue, 14 Aug 2012 19:44:37 +0300

...your huddled checklists, yearning to breathe free.

OK, I can't actually help out with the tired and poor until I get the checklists, so let's start with those.
Continue reading "Give me your tired, your poor..."

PostgreSQL Archeology

nospam@example.com (David Fetter) — Tue, 07 Aug 2012 21:56:26 +0300

It's happened to all of us. We're faced with a system we have only limited access to administer, and something is Not Right.

What's to do?
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VIEW triggers RETURNING...

nospam@example.com (David Fetter) — Mon, 11 Jun 2012 19:39:23 +0300

Thanks to alecm on freenode for the idea. Thanks also to Andres Freund for pointing out a hole in the first implementation.

Access control is an excellent reason for allowing writes to a VIEW but not to the underlying table. You would ideally like that VIEW to act exactly like a TABLE, but when you put an INSTEAD OF trigger in there, what's coming back isn't necessarily what you'd expect...

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Conferety-conf-conf-conf

nospam@example.com (David Fetter) — Thu, 03 Feb 2011 16:24:41 +0200

I'm at the very exciting PostgreSQL Sessions in Paris, where I just talked about DBI-Link, and

where I'll talk about PL/Parrot to a frighteningly large room.

Continue reading "Conferety-conf-conf-conf"

Kick 'em out, and keep 'em out!

nospam@example.com (David Fetter) — Fri, 22 Oct 2010 01:02:19 +0300

It's sad, really. You're about to move a database to archival storage, possibly to /dev/null, but pesky users keep talking to it.
Continue reading "Kick 'em out, and keep 'em out!"

GRAPHical SQL (or how to make a forest)

nospam@example.com (David Fetter) — Thu, 16 Sep 2010 03:47:58 +0300

Graphs? In Databases? Yes, you can!
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MVC Backups

nospam@example.com (David Fetter) — Sat, 24 Jul 2010 19:18:11 +0300

Since Josh Drake has failed to allow comments on his very excellent blog, especially this post,I have to respond below.
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Tablespaces in a (nut)shell

nospam@example.com (David Fetter) — Wed, 09 Jun 2010 20:16:37 +0300

Sometimes, you run across traces of LarryDB. One typical one is a profusion of tablespaces.

Until you solve that problem, you'll need to deal with them. Let's take setting up a warm standby.

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Part(ition)ing Glances

nospam@example.com (David Fetter) — Wed, 05 May 2010 02:24:24 +0300

In an earlier installment, we learned about how to partition a
referenced table, which was good as far as it went. A commenter very
astutely pointed out that this didn't work with RETURNING, so I set
to work fixing that problem.

Here's what I came up with.

Continue reading "Part(ition)ing Glances"

psql, Paste, Perl: Pefficiency!

nospam@example.com (David Fetter) — Tue, 27 Apr 2010 07:38:45 +0300

Enough alliteration already!

I was looking at Regina Obe's excellent piece on how to use psql to do an import on fixed-width data, and thought to myself, "self, how would you do this with fewer copies, just in case you happened across a few hundred gigs of data?"

Here's what I came up with:

Continue reading "psql, Paste, Perl: Pefficiency!"

File-driven Include and Exclude for pg_dump

nospam@example.com (David Fetter) — Fri, 23 Apr 2010 02:06:34 +0300

So you're about to start replicating part of a database using Slony, and you'd rather not set up your replicas with all the extra cruft. You've made your list, but what to do with it?

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The Cloud Under the Lamp Post

nospam@example.com (David Fetter) — Wed, 14 Apr 2010 22:12:57 +0300

A drunk is under a lamp post. It's late at night, and he is crawling
around on his hands and knees, searching frantically all over the tiny
pool of brilliant light it casts. A passer-by asks him, "what are you
doing?" He answers, "I'm looking for my keys." Pointing out into the
darkness, he continues, "I dropped them over there, but the light's
much better over here."

The joke is an old one, and illustrates an interesting truth about
human psychology.

What does this have to do with The Cloud, you ask?

Read on.

Continue reading "The Cloud Under the Lamp Post"

Partly Cloudy, with a Very High Chance of FAIL

nospam@example.com (David Fetter) — Tue, 06 Apr 2010 04:48:19 +0300

Everywhere you turn, it's "cloud" this, "cloud" that, "cloud" the other.
Public clouds, private clouds, hybrid
clouds, fluffy clouds...but somewhere in all that billowing haze,
there's an actual use case.

The people who designed cloud computing made certain explicit
trade-offs, some of which have been lost in all the hype. Given those
explicit trade-offs, your application is a candidate for "the cloud" in
general only if it has all of the following characteristics:

- Embarrassingly parallelizable
- Does not have bounded latency requirements
- Needs CPU much more than I/O
- Tolerant to partial data loss

Continue reading "Partly Cloudy, with a Very High Chance of FAIL"