From 73b6095e13ef6be47fcabd65fcdd9c814bb9b375 Mon Sep 17 00:00:00 2001 From: Gaurish Sharma Date: Sun, 2 Jun 2013 18:24:07 +0530 Subject: [PATCH] Add notes about database connection pool [ci skip] --- guides/source/configuring.md | 11 +++++++++++ .../app/templates/config/databases/postgresql.yml | 2 ++ 2 files changed, 13 insertions(+) diff --git a/guides/source/configuring.md b/guides/source/configuring.md index 5f170474ee..c499cd0727 100644 --- a/guides/source/configuring.md +++ b/guides/source/configuring.md @@ -759,4 +759,15 @@ Since the connection pooling is handled inside of Active Record by default, all Any one request will check out a connection the first time it requires access to the database, after which it will check the connection back in, at the end of the request, meaning that the additional connection slot will be available again for the next request in the queue. +If you try to use more connections than are available, Active Record will block +and wait for a connection from the pool. When it cannot get connection, a timeout +error similar to given below will be thrown. + +```ruby +ActiveRecord::ConnectionTimeoutError - could not obtain a database connection within 5 seconds. The max pool size is currently 5; consider increasing it: +``` + +If you get the above error, you might want to increase the size of connection +pool by incrementing the `pool` option in `database.yml` + NOTE. If you have enabled `Rails.threadsafe!` mode then there could be a chance that several threads may be accessing multiple connections simultaneously. So depending on your current request load, you could very well have multiple threads contending for a limited amount of connections. diff --git a/railties/lib/rails/generators/rails/app/templates/config/databases/postgresql.yml b/railties/lib/rails/generators/rails/app/templates/config/databases/postgresql.yml index eb569b7dab..0194dce6f3 100644 --- a/railties/lib/rails/generators/rails/app/templates/config/databases/postgresql.yml +++ b/railties/lib/rails/generators/rails/app/templates/config/databases/postgresql.yml @@ -55,6 +55,8 @@ production: adapter: postgresql encoding: unicode database: <%= app_name %>_production + # For details on connection pooling, see rails configration guide + # http://guides.rubyonrails.org/configuring.html#database-pooling pool: 5 username: <%= app_name %> password: