concurrent database hit performance issues

rubyonrails-talk
1

After load testing my app, it started getting errors at 6 concurrent users on a not-at-all heavy SQL operation page and I want to know how to reduce these. I've read up about Connection Pooling but the information out there is scarce. I'd like to increase my pool limit to about 25-40 but what are the possible negative repercussions?

The API docs say I must also return the connections to the pool after they're done being used with:

ActiveRecord::Base.clear_active_connections!

However, where does this line of code go? And what line of code goes into database.yml to increase the pool size?

Thanks

2

Add

  pool: 10

for example amongst the settings for each environment. In a 'normal' rails app where you aren't creating threads yourself connections should be returned to the pool for you. If you are creating threads, then you should close the connection at the end of the thread's execution e.g.

Thread.new do    begin       ....    ensure      ActiveRecord::Base.connection.close    end end

In terms of the downsides i think it's just that the database has potentially more connections to handle.

Fred

3

Certainly not using Thread.new yet.

Thanks Fred.