Combine delete and insert statements in the same query

activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb

@@ -372,12 +372,13 @@ def insert_fixtures_set(fixture_set, tables_to_delete = [])
           build_fixture_sql(fixtures, table_name)
         end.compact
 
-        total_sql = Array.wrap(combine_multi_statements(fixture_inserts, tables_to_delete))
+        table_deletes = tables_to_delete.map { |table| "DELETE FROM #{quote_table_name table}".dup }
+        total_sql = Array.wrap(combine_multi_statements(table_deletes + fixture_inserts))
 
         disable_referential_integrity do
           transaction(requires_new: true) do
             total_sql.each do |sql|
-              execute sql, "Fixtures Insert"
+              execute sql, "Fixtures Load"
               yield if block_given?
             end
           end
@@ -445,10 +446,8 @@ def build_fixture_sql(fixtures, table_name)
           manager.to_sql
         end
 
-        def combine_multi_statements(fixture_inserts, tables_to_delete)
-          tables_to_delete.each { |table| delete "DELETE FROM #{quote_table_name(table)}", "Fixture Delete" }
-
-          fixture_inserts.join(";\n")
+        def combine_multi_statements(total_sql)
+          total_sql.join(";\n")
         end
 
         # Returns a subquery for the given key using the join information.

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -545,14 +545,12 @@ def insert_fixtures_set(fixture_set, tables_to_delete = [])
 
       private
 
-        def combine_multi_statements(fixture_inserts, tables_to_delete)
-          super
-
-          fixture_inserts.each_with_object([]) do |sql, total_sql|
-            previous_packet = total_sql.last
+        def combine_multi_statements(total_sql)
+          total_sql.each_with_object([]) do |sql, total_sql_chunks|
+            previous_packet = total_sql_chunks.last
             sql << ";\n"
-            if max_allowed_packet_reached?(sql, previous_packet) || total_sql.empty?
-              total_sql << sql
+            if max_allowed_packet_reached?(sql, previous_packet) || total_sql_chunks.empty?
+              total_sql_chunks << sql
             else
               previous_packet << sql
             end