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| author | Stan Hu <stanhu@gmail.com> | 2018-05-31 00:14:24 -0700 |
|---|---|---|
| committer | Stan Hu <stanhu@gmail.com> | 2018-05-31 00:18:05 -0700 |
| commit | ef253a1ee7c03edf9773574a843b5c458e9add36 (patch) | |
| tree | 57e4d1d49aa0107351a19b74d92542327a9a8065 | |
| parent | 37a7b590c6b7a881ed014f99571a1f44cb45acab (diff) | |
| download | gitlab-ce-ef253a1ee7c03edf9773574a843b5c458e9add36.tar.gz | |
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.
| -rw-r--r-- | changelogs/unreleased/sh-fix-issue-api-perf-n-plus-one.yml | 5 | ||||
| -rw-r--r-- | lib/api/issues.rb | 2 |
2 files changed, 6 insertions, 1 deletions
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 diff --git a/lib/api/issues.rb b/lib/api/issues.rb index 6d75e8817c4..b64f465ce56 100644 --- a/lib/api/issues.rb +++ b/lib/api/issues.rb @@ -16,7 +16,7 @@ module API args[:scope] = args[:scope].underscore if args[:scope] issues = IssuesFinder.new(current_user, args).execute - .preload(:assignees, :labels, :notes, :timelogs) + .preload(:assignees, :labels, :notes, :timelogs, :project) issues.reorder(args[:order_by] => args[:sort]) end |