I had reason to look into the extended secondary index code in MariaDB and MySQL recently, and there was one bit that I really didn’t like.
share->set_use_ext_keys_flag(legacy_db_type == DB_TYPE_INNODB);
use_extended_sk= (legacy_db_type == DB_TYPE_INNODB);
In case you were wondering what “legacy_db_type” actually does, let me tell you: it’s not legacy at all, it’s kind of key to how the whole “metadata” system in MySQL works. For example, to drop a table, this magic number is used to work out what storage engine to call to drop the table.
Now, these code snippets[Read more...]