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Category Archives: Performance

Jan
08
2012

Don’t use strip_tags.

I ran into a rather surprising little problem earlier this week that I felt bore documenting. It turns out that the “simple” Rails strip_tags helper is massive overkill when you just want to strip markup out of a document. It offers a lot of functionality, but it comes at a pretty ugly performance cost. Here’s [...]

By Chris Heald | Also posted in Rails, Ruby | Comments (0)
Jul
17
2011

MongoDB, count() and the big O

MongoDB, as I’ve mentioned before, is not without its warts. I’ve run into another, and it’s a nasty one. It turns out that if you perform count() on a query cursor that includes any conditions, even if those conditions are indexed, the operation takes O(n) time to run. In practice, I’ve found that this costs [...]

By Chris Heald | Also posted in MongoDB, Ruby | Tagged , | Comments (0)
Jun
17
2011

Making HAML faster

Haml’s among my favorite of the Rails technology stack. Clean, self-correcting templates that mean less typing and more doing for me. I love it. Unfortunately, there have been a number of performance regressions introduced into Haml recently, and that sucks, because Rails spends a lot of time building views, and I’d really like those numbers [...]

By Chris Heald | Also posted in Ruby | Comments (9)
Jun
17
2011

JRuby Performance: Exceptions are not flow control

I started playing with JRuby tonight, and got my application up and running on it in under 10 minutes (kudos to the JRuby team!), but when I started measuring its performance, I was seriously unimpressed. This didn’t quite line up with what I’ve read of JRuby, so I decided to do a little digging.

By Chris Heald | Also posted in JRuby, Ruby | Comments (11)
Aug
23
2010

Debugging memory leaks in Ruby with GDB, round 2.

In part 1, I described how I located leaky Sets in MongoMapper by diffing the Ruby ObjectSpace with GDB. Today, I’m going to show you how to solve the problems that those sorts of diffs can reveal. In today’s example, we’re tracking leaky sets. In particular, a set is holding onto class references. We are [...]

By Chris Heald | Also posted in MongoDB, Ruby | Tagged , | Comments (0)
Aug
23
2010

MongoMapper, Development Mode, and Memory Leaks

If you’ve worked with MongoMapper for a while, you’ve probably noticed that in complex apps, there are horrific memory leaks in development that magically disappear in production mode. While this is all well and good, and it’s rather handy that things Just Work in production, don’t you wish you didn’t have to restart your app [...]

By Chris Heald | Also posted in MongoDB, Ruby | Tagged , , , , | Comments (2)
Jul
29
2009

Sweet-ass performance hacks: better_assets

HTTP overhead is expensive. DNS lookups are expensive. Start dropping a bunch of Twitter widgets, Google ads, and GetSatisfaction buttons into your killer new Web 2.0 social networking site and you’ll find that your painstakingly-optimized site has slowed to a crawl while the server sits there waiting on Amazon S3 to get its act together [...]

By Chris Heald | Also posted in Rails | Comments (1)