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| -rw-r--r-- | doc/development/query_recorder.md | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/doc/development/query_recorder.md b/doc/development/query_recorder.md index 26d3355e94d..61e5e1afede 100644 --- a/doc/development/query_recorder.md +++ b/doc/development/query_recorder.md @@ -22,6 +22,19 @@ As an example you might create 5 issues in between counts, which would cause the > **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: + +it "avoids N+1 database queries" 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) +end +``` + ## Finding the source of the query It may be useful to identify the source of the queries by looking at the call backtrace. |