From 1b0c71ef8423cf20532953e58735dd7f61325e85 Mon Sep 17 00:00:00 2001 From: Stan Hu Date: Tue, 18 Jun 2019 13:50:46 -0700 Subject: [PATCH] Cache feature flag names in Redis for a minute We saw on GitLab.com, the SQL query, `SELECT "features"."key" FROM "features"` peaked at 2300 times per second. We can quiet this down a bit by caching it in Redis for a minute. Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63435 --- changelogs/unreleased/sh-cache-feature-flag-names.yml | 5 +++++ lib/feature.rb | 7 ++++++- spec/lib/feature_spec.rb | 9 ++++++++- 3 files changed, 19 insertions(+), 2 deletions(-) create mode 100644 changelogs/unreleased/sh-cache-feature-flag-names.yml diff --git a/changelogs/unreleased/sh-cache-feature-flag-names.yml b/changelogs/unreleased/sh-cache-feature-flag-names.yml new file mode 100644 index 00000000000..6120c4870f8 --- /dev/null +++ b/changelogs/unreleased/sh-cache-feature-flag-names.yml @@ -0,0 +1,5 @@ +--- +title: Cache feature flag names in Redis for a minute +merge_request: 29816 +author: +type: performance diff --git a/lib/feature.rb b/lib/feature.rb index 749c861d740..cc9c9d44005 100644 --- a/lib/feature.rb +++ b/lib/feature.rb @@ -30,7 +30,12 @@ class Feature end def persisted_names - Gitlab::SafeRequestStore[:flipper_persisted_names] ||= FlipperFeature.feature_names + Gitlab::SafeRequestStore[:flipper_persisted_names] ||= + begin + # We saw on GitLab.com, this database request was called 2300 + # times/s. Let's cache it for a minute to avoid that load. + Rails.cache.fetch('flipper:persisted_names', expires_in: 1.minute) { FlipperFeature.feature_names } + end end def persisted?(feature) diff --git a/spec/lib/feature_spec.rb b/spec/lib/feature_spec.rb index a7163048370..6f05914f915 100644 --- a/spec/lib/feature_spec.rb +++ b/spec/lib/feature_spec.rb @@ -31,7 +31,8 @@ describe Feature do expect(described_class.persisted_names).to be_empty end - it 'caches the feature names when request store is active', :request_store do + it 'caches the feature names when request store is active', + :request_store, :use_clean_rails_memory_store_caching do Feature::FlipperFeature.create!(key: 'foo') expect(Feature::FlipperFeature) @@ -39,6 +40,12 @@ describe Feature do .once .and_call_original + expect(Rails.cache) + .to receive(:fetch) + .once + .with('flipper:persisted_names', expires_in: 1.minute) + .and_call_original + 2.times do expect(described_class.persisted_names).to eq(%w[foo]) end