From 978647c6cb0f81c3695c4d20e98619c2025532c5 Mon Sep 17 00:00:00 2001 From: Stan Hu Date: Mon, 1 Jul 2019 12:17:37 -0700 Subject: Add a memory cache local to the thread to reduce Redis load Loading `ApplicationSetting` from Redis was responsible for at least 50% of the CPU load of the Redis cluster on GitLab.com. Since these values generally don't change very much, we can load this from the database and cache it in memory, skipping Redis altogther. We use `ActiveSupport::Cache::MemoryStore` as a drop-in replacement for `RedisCacheStore` even though we probably don't need synchronized access within `Thread.current`. Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63977 --- app/models/application_setting.rb | 8 ++++++++ app/models/concerns/cacheable_attributes.rb | 10 +++++++--- 2 files changed, 15 insertions(+), 3 deletions(-) (limited to 'app/models') diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb index fbd8036653a..8e558487c1c 100644 --- a/app/models/application_setting.rb +++ b/app/models/application_setting.rb @@ -272,4 +272,12 @@ class ApplicationSetting < ApplicationRecord # We already have an ApplicationSetting record, so just return it. current_without_cache end + + # By default, the backend is Rails.cache, which uses + # ActiveSupport::Cache::RedisStore. Since loading ApplicationSetting + # can cause a significant amount of load on Redis, let's cache it in + # memory. + def self.cache_backend + Gitlab::ThreadMemoryCache.cache_backend + end end diff --git a/app/models/concerns/cacheable_attributes.rb b/app/models/concerns/cacheable_attributes.rb index 3d60f6924c1..8cbf4bcfaf7 100644 --- a/app/models/concerns/cacheable_attributes.rb +++ b/app/models/concerns/cacheable_attributes.rb @@ -36,7 +36,7 @@ module CacheableAttributes end def retrieve_from_cache - record = Rails.cache.read(cache_key) + record = cache_backend.read(cache_key) ensure_cache_setup if record.present? record @@ -58,7 +58,7 @@ module CacheableAttributes end def expire - Rails.cache.delete(cache_key) + cache_backend.delete(cache_key) rescue # Gracefully handle when Redis is not available. For example, # omnibus may fail here during gitlab:assets:compile. @@ -69,9 +69,13 @@ module CacheableAttributes # to be loaded when read from cache: https://github.com/rails/rails/issues/27348 define_attribute_methods end + + def cache_backend + Rails.cache + end end def cache! - Rails.cache.write(self.class.cache_key, self, expires_in: 1.minute) + self.class.cache_backend.write(self.class.cache_key, self, expires_in: 1.minute) end end -- cgit v1.2.1