https://bhaak.net/blog/tags/performance/ Recent content in Performance on Bhaak's Blog Hugo en-us Thu, 14 May 2026 15:23:13 +0200 https://bhaak.net/blog/posts/2026-05-14-accessing-activerecord-attribute-slower-than-local-variable/ Thu, 14 May 2026 15:23:13 +0200 https://bhaak.net/blog/posts/2026-05-14-accessing-activerecord-attribute-slower-than-local-variable/ <p>I was deep in a performance optimization flow when I stumbled upon this part in <a href="https://github.com/ruby-prof/ruby-prof">a ruby-prof graph</a>:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-text" data-lang="text"><span style="display:flex;"><span>- 17.59% (73.45%) SomeTable::GeneratedAttributeMethods#some_attribute [30263106 calls, 44665545 total] </span></span><span style="display:flex;"><span> - 15.24% (86.62%) ActiveRecord::AttributeMethods::Read#_read_attribute [30263106 calls, 49437307 total] </span></span><span style="display:flex;"><span> - 11.82% (77.58%) ActiveModel::AttributeSet#fetch_value [30263106 calls, 49068748 total] </span></span><span style="display:flex;"><span> - 5.44% (46.06%) ActiveModel::AttributeSet#[] [30263106 calls, 49303667 total] </span></span><span style="display:flex;"><span> - 2.32% (42.58%) Hash#[] [30263106 calls, 72892138 total] </span></span><span style="display:flex;"><span> - 2.05% (17.36%) ActiveModel::Attribute#value [30263106 calls, 49274896 total] </span></span></code></pre></div><p>ActiveRecord stores attributes internally in a hash, which is more expensive than I expected.</p>