diff options
Diffstat (limited to 'guides/source/active_record_querying.md')
| -rw-r--r-- | guides/source/active_record_querying.md | 39 |
1 files changed, 0 insertions, 39 deletions
diff --git a/guides/source/active_record_querying.md b/guides/source/active_record_querying.md index 62d6294ae5..bc3b1669d2 100644 --- a/guides/source/active_record_querying.md +++ b/guides/source/active_record_querying.md @@ -1609,45 +1609,6 @@ EXPLAIN for: SELECT `posts`.* FROM `posts` WHERE `posts`.`user_id` IN (1) under MySQL. -### Automatic EXPLAIN - -Active Record is able to run EXPLAIN automatically on slow queries and log its -output. This feature is controlled by the configuration parameter - -```ruby -config.active_record.auto_explain_threshold_in_seconds -``` - -If set to a number, any query exceeding those many seconds will have its EXPLAIN -automatically triggered and logged. In the case of relations, the threshold is -compared to the total time needed to fetch records. So, a relation is seen as a -unit of work, no matter whether the implementation of eager loading involves -several queries under the hood. - -A threshold of `nil` disables automatic EXPLAINs. - -The default threshold in development mode is 0.5 seconds, and `nil` in test and -production modes. - -INFO. Automatic EXPLAIN gets disabled if Active Record has no logger, regardless -of the value of the threshold. - -#### Disabling Automatic EXPLAIN - -Automatic EXPLAIN can be selectively silenced with `ActiveRecord::Base.silence_auto_explain`: - -```ruby -ActiveRecord::Base.silence_auto_explain do - # no automatic EXPLAIN is triggered here -end -``` - -That may be useful for queries you know are slow but fine, like a heavyweight -report of an admin interface. - -As its name suggests, `silence_auto_explain` only silences automatic EXPLAINs. -Explicit calls to `ActiveRecord::Relation#explain` run. - ### Interpreting EXPLAIN Interpretation of the output of EXPLAIN is beyond the scope of this guide. The |