PostgreSQL as a secret weapon for high-performance ... - PGCon

Rails Performance > Preloading Attributes
Faster with Postgres arrays:
Tasks Tags Tasks_Tags
id serial id serial tag_id integer
name varchar name varchar task_id integer
tasks = Task.find(:all, :select => "*,
array(select tags.name from tags inner join tasks_tags
on (tags.id = tasks_tags.tag_id)
where tasks_tasks.task_id=tasks.id) as tag_names
")
puts tasks.first.tag_names
> "{Foo,Bar,Zee}"
Gleb Arshinov & Alex Dymo ● PostgreSQL as a secret weapon for high-performance Ruby on Rails applications ● PGCon 2010 32 / 58