This function is actually a combination of two functions in mnesia(:mnesia.info(), :mnesia.schema()).

Example:

  MnesiaAssistant.Information.info()
  # OR
  MnesiaAssistant.Information.info({:system, type})
  # OR
  MnesiaAssistant.Information.info(type)

All types you can use:

  [
    :all,
    :access_module,
    :auto_repair,
    :backup_module,
    :checkpoints,
    :event_module,
    :db_nodes,
    :debug,
    :directory,
    :dump_log_load_regulation,
    :dump_log_time_threshold,
    :dump_log_update_in_place,
    :dump_log_write_threshold,
    :extra_db_nodes,
    :fallback_activated,
    :held_locks,
    :is_running,
    :local_tables,
    :lock_queue,
    :log_version,
    :master_node_tables,
    :protocol_version,
    :running_db_nodes,
    :schema_location,
    :subscribers,
    :tables,
    :transactions,
    :transaction_failures,
    :transaction_commits,
    :transaction_restarts,
    :transaction_log_writes,
    :use_dir,
    :version,
    :schema
  ]

Read info/0 document.

If the application detects a communication failure (in a potentially partitioned network) that can have caused an inconsistent database, it can use the function mnesia:set_master_nodes(Tab, MasterNodes) to define from which nodes each table is to be loaded. At startup, the Mnesia normal table load algorithm is bypassed and the table is loaded from one of the master nodes defined for the table, regardless of when and if Mnesia terminated on other nodes. MasterNodes can only contain nodes where the table has a replica. If the MasterNodes list is empty, the master node recovery mechanism for the particular table is reset, and the normal load mechanism is used at the next restart.

The master node setting is always local. It can be changed regardless if Mnesia is started or not.

The database can also become inconsistent if configuration parameter max_wait_for_decision is used or if mnesia:force_load_table/1 is used.

Example:

  MnesiaAssistant.Information.set_debug_level(level)

All level you can use: [:none, :verbose, :debug, :trace, false, true]

Ensures that the local transaction log file is synced to disk. On a single node system, data written to disk tables since the last dump can be lost if there is a power outage.

Example:

  MnesiaAssistant.Information.sync_log()

Read info/0 document.