Hi Timour, I was working on BUG#868908, which involves having different kind of handling for cases where Materialization is not applicable because temp table had the wrong properties. So, I've set a goal to catch such cases: === modified file 'sql/item_subselect.cc' --- sql/item_subselect.cc 2011-12-06 21:03:00 +0000 +++ sql/item_subselect.cc 2011-12-06 21:11:16 +0000 @@ -4182,6 +4182,8 @@ bool subselect_hash_sj_engine::init(List */ if (tmp_table->s->keys == 0) { + //fprintf(stderr, "Q: %s\n", current_thd->query()); + DBUG_ASSERT(0); DBUG_ASSERT( tmp_table->s->uniques || tmp_table->key_info->key_length >= tmp_table->file->max_key_length() || Surprisingly, running mysql-test-run t/subselect*.test with this didn't produce any failures. Is this poor test coverage? Or, this branch is now deadcode? BR Sergei -- Sergei Petrunia, Software Developer Monty Program AB, http://askmonty.org Blog: http://s.petrunia.net/blog