diff options
| author | Ryuta Kamizono <kamipo@gmail.com> | 2018-10-10 05:31:20 +0900 |
|---|---|---|
| committer | Ryuta Kamizono <kamipo@gmail.com> | 2018-10-10 05:31:20 +0900 |
| commit | 92ccb7c75fd0d07479ea3b458b405b8e6667e05f (patch) | |
| tree | 5b68a28c358ebe0009e41c4544eba6729db363b9 /activerecord/lib/arel/visitors/to_sql.rb | |
| parent | 3101a4136bd62787e252d2658eee23001036fa0f (diff) | |
| download | rails-92ccb7c75fd0d07479ea3b458b405b8e6667e05f.tar.gz rails-92ccb7c75fd0d07479ea3b458b405b8e6667e05f.tar.bz2 rails-92ccb7c75fd0d07479ea3b458b405b8e6667e05f.zip | |
Improve DELETE with JOIN handling to avoid subqueries if possible
Before:
```
Pet Destroy (0.8ms) DELETE FROM `pets` WHERE `pets`.`pet_id` IN (SELECT `pet_id` FROM (SELECT DISTINCT `pets`.`pet_id` FROM `pets` LEFT OUTER JOIN `toys` ON `toys`.`pet_id` = `pets`.`pet_id` WHERE `toys`.`name` = ?) AS __active_record_temp) [["name", "Bone"]]
```
After:
```
Pet Destroy (1.0ms) DELETE `pets` FROM `pets` LEFT OUTER JOIN `toys` ON `toys`.`pet_id` = `pets`.`pet_id` WHERE `toys`.`name` = ? [["name", "Bone"]]
```
Diffstat (limited to 'activerecord/lib/arel/visitors/to_sql.rb')
| -rw-r--r-- | activerecord/lib/arel/visitors/to_sql.rb | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/activerecord/lib/arel/visitors/to_sql.rb b/activerecord/lib/arel/visitors/to_sql.rb index 7c0f6c2e97..a55450956b 100644 --- a/activerecord/lib/arel/visitors/to_sql.rb +++ b/activerecord/lib/arel/visitors/to_sql.rb @@ -76,7 +76,13 @@ module Arel # :nodoc: all def visit_Arel_Nodes_DeleteStatement(o, collector) o = prepare_delete_statement(o) - collector << "DELETE FROM " + if has_join_sources?(o) + collector << "DELETE " + visit o.relation.left, collector + collector << " FROM " + else + collector << "DELETE FROM " + end collector = visit o.relation, collector collect_where_for(o, collector) |