It’s Monday, and a blizzard in the Lake Tahoe area has stranded several of our developer. No interesting things for standup today.
Hoping to improve performance, we changed a query to use the :include condition like this:
Project.find(id, :include => :stories)
and we noticed two things:
- ActiveRecord decided to turn that into a LEFT OUTER JOIN. Egads! This drastically slowed things down (although we didn’t notice until several days later, when we ran a real load test with production data).
- acts_as_paranoid did not manage to stick it’s little “and deleted_at = nil” phrase into the query. This meant that “deleted” stories showed up when they weren’t supposed to.
So that’s two gotchas for the price of one.
In email, Nick pointed out that the joining behavior is documented and appropriate (”otherwise if there is a nil association (eg a project without any stories) you wouldn’t get a project back even though it exists!”) and Miho rejoined that AR can be dangerous because it changes what looks like beautiful, elegant Ruby into nasty, ugly, hard-to-understand SQL under the hood.
Only project updates today.
Never be afraid to refactor. It may seem scary right now, but it will only become more daunting as the code base increases in size.
The right time to refactor is NOW… grasshopper
And now that my pair and I have rallied around this post, to the refactoring!
- Subversion Tip: We were reminded of a handy tip: when saving shell scripts in subversion, you can save them as both executable and also in a ‘native’ end-of-line style, which will run on any platform.
$> svn propset svn:executable ON somescript.sh
$> svn propset svn:eol-style native somescript.sh
- Another handy plugin we’ve used many times: QueryTrace. It helps you find slow database queries, but it really floods your logs with data, so make sure to turn it off in production!
- We’re using appable_plugins for several projects but having problems with dependencies between the plugins, especially in fixtures. This might be caused by our fancy-dancy fixture loading extensions.
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ruby -r profile, and our own custom ruby test benchmarker, amongst others.
- One project is seeing a very strange memory leak that causes 100MB of memory loss per second (guh! guh!). It started when they begin using
ActiveRecord.connection.execute("some sql") to build some reporting statistics, but it seems too early to blame that. Coincidental, though.
Brown Bag Lunch Topic: Rails 1.2 features, ideas, and gotchas.
Total Stand-up Meeting Time: 25:00 minutes
- We’ll be sending 6 people to RailsConf, so say ‘hi’ if you see the Pivots!
- We have a fix to our Amazon S3-causing-mongrel-to-hang problem: you can tell the connection not to be persistent by passing in
:persistent => false:
:access_key_id => access_key,
:secret_access_key => access_key,
:persistent => false
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Total Stand-up Meeting Time: 14:00 minutes
Not much of interest today beyond project updates.
Total Stand-up Meeting Time: 17:00