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Diffstat (limited to 'doc/development/query_recorder.md')
| -rw-r--r-- | doc/development/query_recorder.md | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/doc/development/query_recorder.md b/doc/development/query_recorder.md index ef9a3c657aa..4a02af3348c 100644 --- a/doc/development/query_recorder.md +++ b/doc/development/query_recorder.md @@ -1,3 +1,9 @@ +--- +stage: none +group: unassigned +info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers +--- + # QueryRecorder QueryRecorder is a tool for detecting the [N+1 queries problem](https://guides.rubyonrails.org/active_record_querying.html#eager-loading-associations) from tests. @@ -20,17 +26,17 @@ end As an example you might create 5 issues in between counts, which would cause the query count to increase by 5 if an N+1 problem exists. -NOTE: **Note:** In some cases the query count might change slightly between runs for unrelated reasons. In this case you might need to test `exceed_query_limit(control_count + acceptable_change)`, but this should be avoided if possible. ## Cached queries -By default, QueryRecorder will ignore cached queries in the count. However, it may be better to count -all queries to avoid introducing an N+1 query that may be masked by the statement cache. To do this, -pass the `skip_cached` variable to `QueryRecorder` and use the `exceed_all_query_limit` matcher: +By default, QueryRecorder will ignore [cached queries](merge_request_performance_guidelines.md#cached-queries) in the count. However, it may be better to count +all queries to avoid introducing an N+1 query that may be masked by the statement cache. +To do this, this requires the `:use_sql_query_cache` flag to be set. +You should pass the `skip_cached` variable to `QueryRecorder` and use the `exceed_all_query_limit` matcher: ```ruby -it "avoids N+1 database queries" do +it "avoids N+1 database queries", :use_sql_query_cache do control_count = ActiveRecord::QueryRecorder.new(skip_cached: false) { visit_some_page }.count create_list(:issue, 5) expect { visit_some_page }.not_to exceed_all_query_limit(control_count) @@ -118,4 +124,5 @@ There are multiple ways to find the source of queries. - [Bullet](profiling.md#bullet) For finding `N+1` query problems - [Performance guidelines](performance.md) -- [Merge request performance guidelines](merge_request_performance_guidelines.md#query-counts) +- [Merge request performance guidelines - Query counts](merge_request_performance_guidelines.md#query-counts) +- [Merge request performance guidelines - Cached queries](merge_request_performance_guidelines.md#cached-queries) |