Currently Drill has only one Metastore implementation based on Iceberg tables. Iceberg tables are file based storage that supports concurrent writes / reads but required to be placed on distributed file system.
This Jira aims to implement Drill RDBMS Metastore which will store Drill Metastore metadata in the database of the user's choice. Currently, PostgreSQL and MySQL databases are supported, others might work as well but no testing was done. Also out of box for demonstration / testing purposes Drill will setup SQLite file based embedded database but this is only applicable for Drill in embedded mode.