30 June 2012
For years, the standard log analysis tool for PostgreSQL has been pgfouine (For those wondering, a “fouine” in French is a beech marten; as the saying goes, I am none the wiser, if somewhat better informed.) However, pgfouine seems to have stalled as a project; there haven’t been updates in a while, it requires a patch to work with PostgreSQL 9.1, and it frequently chokes on complex or difficult-to-parse log files. And, well, it’s written in PHP.
Thus, I’m pleased to note a new-ish log analyse, pgbadger. It’s written in Perl, at least as fast as pgfouine, and can process log files that pgfouine can’t handle. It can read either CSV or standard log format, and can directly read *.gz files. It also produces a wider range of reports that pgfouine, including some very useful locking reports. I threw 25GB of logs with near 80 million lines at it without it complaining; it processed between 225 and 335 log lines per second on my laptop.
I am not sure why PostgreSQL log analyzers have adopted a small-mammal naming convention, but I’m pleased to have something else burrowing in the garden.
4 June 2012
3 June 2012
When you are in a business that is engaging in constant warfare with the people who your product is nominally targeted at, you are in a bad business.
18 May 2012
My presentation from PGCon 2012, PostgreSQL on AWS with Reduced Tears, is now up.
25 April 2012
Pickup trucks are great.
No, really. They are great vehicles. You can use them for all sorts of really useful things: Bringing your tools out to a construction gig. Delivering refrigerators. Helping your friend move a sofa. Carting away a reasonable amount of construction debris.
But if you need to deliver 75,000 pounds of steel beams to a construction site, in a single run? A pickup truck will not do it. Not even a big pickup. Not even if you add a new engine. Not even if you are willing to get three pickups. You need equipment designed for that. (And, as a note, the equipment that could handle delivering the steel beams would be a terrible choice for helping a friend move their sofa.)
“But,” I hear you say, “I already know how to drive a pickup! And we have a parking space for it. Can’t we just use the pickup? You’re a truck expert; tell us how to get our pickup to pull that load!”
And I say, “Being a truck expert, I will tell you again, a pickup the wrong kind of truck. There are other trucks that will handle that load with no trouble, but a pickup isn’t one of them. The fact that you have a pickup doesn’t make it the right truck.”
We have many clients that run PostgreSQL, happily, on Amazon Web Services.
Some clients, however, are not happy. They are attempting to haul tractor-trailer loads (such as high volume data warehouses) using pickup trucks (Amazon EC2 instances). They wish us to fix their problem, but are not willing to move off of Amazon in order to get the problem fixed.
I like AWS for a lot of things; it has many virtues, which I will discuss in detail soon. However, AWS is not the right solution for every problem. In particular, if you require a high read or write data rate in order to get the performance you need from your database, you will ultimately not be happy on AWS. AWS has a single block-device storage mechanism, Elastic Block Storage, which simply does not scale up to very high data rates.
That doesn’t mean that AWS is useless, it just means it isn’t the right tool for every job. The problem arises when AWS is considered the fixed point, like the pickup was the fixed point above. At some point, you have to decide:
- That being on AWS is so important (for whatever reason) that you are willing to sacrifice the performance you want; or,
- The performance you want is so important that you will need to move off of AWS.
Sadly, even the best of consultants do not have the magic engine in our back room that will cause EBS to perform as well as high-speed direct attached storage.
Well, I’m not going; are you? This year’s Apple World-Wide Developer’s Conference was sold out by 8am Pacific Time, having gone on sale around 6am. (I missed the boat in 2011 and 2010, too.) I can’t imagine anyone except perhaps Apple thinks that the mad scramble to the keyboard that we’ve experienced in the last few years is a rational way to allocate tickets.
It’s time for Apple to admit that the traditional model of a singular WWDC either requires a venue that can handle the crowd, or split it into multiple, regional events. It would lose the “gathering of the tribe” aspect that has always been one of the best parts of WWDC, but that’s lost now, anyway; the “tribe” is not defined on who was by their keyboards for 90 minutes at 6am on a Wednesday.
If Apple views the WWDC as a way to pack people into seats to create excitement for their announcements early in the week, then I suppose the current system is as good as anything. From any other perspective, it’s time to find another way of doing this.
20 April 2012
First, read this essay about the disaster that is PHP. Every word is correct.
Then, view this photo set.
18 April 2012
I’ll be speaking at the following conferences through July:
- PGCon, Ottawa, Ontario, Canada, May 17-18.
- DjangoCon Europe, Zurich, Switzerland, June 4-6.
- Southwest LinuxFest, Charlotte, North Carolina, June 8-10.
- EuroPython, Florence, Italy, July 2-8.
- OSCON, Portland, Oregon, USA, July 16-20.
13 April 2012
… or, inexcusable things I am tired of seeing in postgresql.conf files.
Do not mix ‘n’ match override styles.
There are two valid styles for overriding the default values in postgresql.conf: Putting your changes as a cluster at the end, or uncommenting the defaults and overriding in place. Both have advantages and disadvantages. Having some settings one way and some another is pure disadvantage. Do not do this.
Quick, what is
log_min_duration_statement set to here?
log_min_statement_duration = 2000
Now, what is it set to here?
log_min_statement_duration = 2s
Always use units with numeric values if a unit is available.
Do not remove the default settings.
If you strip out all of the defaults, it becomes impossible to tell what a particular value is set to. Leave the defaults in place, and if you comment out a setting, reset the value to the default (or at least include comments that make it clear what is going on).
Do not leave junk postgresql.conf files scattered around.
If you need to move postgresql.conf (and the other configuration files) to a different location from where the package for your system puts it, don’t leave the old, dead postgresql.conf lying around. Delete any trace of the old installation hierarchy.
12 April 2012
Instagram has been in the news lately. In this really great post on Tumblr, Instagram talks about its technology stack.
I have some acquaintance with the Instagram people, and they are among the smartest technologists I’ve met. Really nice, too. (Of course, they mention this blog in the post, so I’m biased.)