Merge branch 'ab/partitioning-race' into 'master'

Atomically create table and its partitions

Closes omnibus-gitlab#5597

See merge request gitlab-org/gitlab!41773

lib/gitlab/database/partitioning_migration_helpers/table_management_helpers.rb

@@ -62,8 +62,10 @@ module Gitlab
 
           partitioned_table_name = make_partitioned_table_name(table_name)
 
-          create_range_partitioned_copy(table_name, partitioned_table_name, partition_column, primary_key)
-          create_daterange_partitions(partitioned_table_name, partition_column.name, min_date, max_date)
+          transaction do
+            create_range_partitioned_copy(table_name, partitioned_table_name, partition_column, primary_key)
+            create_daterange_partitions(partitioned_table_name, partition_column.name, min_date, max_date)
+          end
           create_trigger_to_sync_tables(table_name, partitioned_table_name, primary_key)
         end