Typically, the performance issues are at the ActiveRecord level, when it's initialization 100s of instances of an object to render a table. With Rails, the #1 optimization technique is to use `ActiveRecord::Base.connection.exec_query ` to return a hash instead of initialization objects.
Side note: I still love Rails.
A little bit of knowledge about SQL and how a relational database works goes a long way.
Adding an index for a query can take it from seconds to me for the average response.
Side note: I really dislike Rails.
no it doesn't. It only wraps updates in transactions, and a single line update would have an implicit transaction at the database anyway.
Think about what we both wrote here (sans the weak man argument, of course I'm talking about updates).
Rails does the right thing here in my opinion. Anything that happens between calling `.save` and it returning should be in the safe envelop of a transaction. It can't know that you're only going to emit a single UPDATE query in that transaction, plus the framework user expects any exception between calling save and it returning to roll back. There are outs if you need them. I've worked on a few reasonably high traffic and complex rails applications and I don't recall a time when the time between the last query and the commit caused an issue. Yes times when the transaction itself had got too large and that commit was taking awhile. That said, there were more of these types of locking issues in the project I worked on 10 years ago with MySQL and repeatable read isolation level than with PG since then which defaults to read committed.