Speed up commit loads by disabling BatchLoader replace_methods

In production, we've seen the rendering times of the merge request widget increase as a result of loading commit data. BatchLoader attempts to call replace_methods on the lazy object, but this has a significant performance penalty for modules that have many methods. Disabling this mode (exAspArk/batch-loader#45) appears to cut load times by about 50% for MergeRequestsController#show. Relates to https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/6941
tigefa4u · Jun 13, 2019 · 9a09e20 · 9a09e20
1 parent 21bf855
commit 9a09e20
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diff --git a/app/models/commit.rb b/app/models/commit.rb
@@ -94,7 +94,7 @@ def valid_hash?(key)
     end
 
     def lazy(project, oid)
-      BatchLoader.for({ project: project, oid: oid }).batch do |items, loader|
+      BatchLoader.for({ project: project, oid: oid }).batch(replace_methods: false) do |items, loader|
         items_by_project = items.group_by { |i| i[:project] }
 
         items_by_project.each do |project, commit_ids|

diff --git a/changelogs/unreleased/sh-speed-up-commit-loading.yml b/changelogs/unreleased/sh-speed-up-commit-loading.yml
@@ -0,0 +1,5 @@
+---
+title: Speed up commit loads by disabling BatchLoader replace_methods
+merge_request:
+author:
+type: performance