From ef253a1ee7c03edf9773574a843b5c458e9add36 Mon Sep 17 00:00:00 2001 From: Stan Hu Date: Thu, 31 May 2018 00:14:24 -0700 Subject: Eliminate cached N+1 queries for projects in Issue API In CE, every `Issue` entity is also a `ProjectEntity`, which calls `entity&.project.try(:id)` to show the project ID. In an API request with 100 issues, this would hit the Rails statement cache 100 times for the same project and cause unnecessary overhead as related models would also be loaded. In EE, we call `Issue#supports_weight?` for each issue, which then calls `project&.feature_available?(:issue_weights)`. If the project is not preloaded, this incurs additional overhead, as each individual Project object has to be queried. This can lead to a significant performance hit. In loading the CE project with 100 issues, this contributed to at least 22% of the load time. See https://gitlab.com/gitlab-org/gitlab-ce/issues/47031 for why testing this is a bit tricky. --- changelogs/unreleased/sh-fix-issue-api-perf-n-plus-one.yml | 5 +++++ 1 file changed, 5 insertions(+) create mode 100644 changelogs/unreleased/sh-fix-issue-api-perf-n-plus-one.yml (limited to 'changelogs') diff --git a/changelogs/unreleased/sh-fix-issue-api-perf-n-plus-one.yml b/changelogs/unreleased/sh-fix-issue-api-perf-n-plus-one.yml new file mode 100644 index 00000000000..57ba081326f --- /dev/null +++ b/changelogs/unreleased/sh-fix-issue-api-perf-n-plus-one.yml @@ -0,0 +1,5 @@ +--- +title: Eliminate cached N+1 queries for projects in Issue API +merge_request: +author: +type: performance -- cgit v1.2.1