instance method `retrieve_connection_pool`

Ruby on Rails 4.0.13

Since v2.2.3

Available in: v2.2.3 v2.3.18 v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

retrieve_connection_pool(klass)

Retrieving the connection pool happens a lot so we cache it in @class_to_pool. This makes retrieving the connection pool O(1) once the process is warm. When a connection is established or removed, we invalidate the cache.

Ideally we would use #fetch here, as class_to_pool may sometimes be nil. However, benchmarking (gist.github.com/jonleighton/3552829) showed that #fetch is significantly slower than #[]. So in the nil case, no caching will take place, but that’s ok since the nil case is not the common one that we wish to optimise for.

Parameters

klass req

Source

# File activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb, line 578
      def retrieve_connection_pool(klass)
        class_to_pool[klass.name] ||= begin
          until pool = pool_for(klass)
            klass = klass.superclass
            break unless klass <= Base
          end

          class_to_pool[klass.name] = pool
        end
      end

Defined in activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb line 578 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::ConnectionAdapters::ConnectionHandler

Signature

Parameters