Perf: Don't load the association for #delete_all.

Bug #6289

Conflicts:

	activerecord/test/cases/associations/has_many_associations_test.rb

1 files changed, 11 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index a4cea99372..e8ae3e51b9 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -46,11 +46,17 @@ module ActiveRecord
           if sql = options[:delete_sql]
             records.each { |record| owner.connection.delete(interpolate(sql, record)) }
           else
-            relation = join_table
-            stmt = relation.where(relation[reflection.foreign_key].eq(owner.id).
-              and(relation[reflection.association_foreign_key].in(records.map { |x| x.id }.compact))
-            ).compile_delete
-            owner.connection.delete stmt
+            relation  = join_table
+            condition = relation[reflection.foreign_key].eq(owner.id)
+
+            unless records == :all
+              condition = condition.and(
+                relation[reflection.association_foreign_key]
+                  .in(records.map { |x| x.id }.compact)
+              )
+            end
+
+            owner.connection.delete(relation.where(condition).compile_delete)
           end
         end