The :mnesia.change_config/2 function in Mnesia, the distributed database management system in Erlang/OTP, is used to dynamically change the configuration parameters of the Mnesia system while it is running.

This function allows you to adjust certain operational parameters of Mnesia without needing to stop and restart the database, making it particularly useful for tuning performance or behavior in live systems.

• config: --> extra_db_nodes | dc_dump_limit

• value: --> [node()] | number()

Example

  MnesiaAssistant.change_config(config, value)copy

See MishkaDeveloperTools.Helper.Extra.erlang_guard/1.

See MishkaDeveloperTools.Helper.Extra.erlang_result/1.

See MishkaDeveloperTools.Helper.Extra.erlang_fields/4.

See MnesiaAssistant.Information.info/0.

See MnesiaAssistant.Information.info/1.

When tracing a system of Mnesia applications it is useful to be able to interleave Mnesia own events with application-related events that give information about the application context.

Whenever the application begins a new and demanding Mnesia task, or if it enters a new interesting phase in its execution, it can be a good idea to use mnesia:report_event/1. Event can be any term and generates a {mnesia_user, Event} event for any processes that subscribe to Mnesia system events. for more information read subscribe/1 document.

Example:

MnesiaAssistant.report_event(event)copy

See MnesiaAssistant.Schema.schema/0.

See MnesiaAssistant.Schema.schema/1.

See MnesiaAssistant.Information.set_debug_level/1.

The mnesia database provides you with the capability to perform your storage either on the hard drive or on the RAM, or both at the same time, depending on the software approach that you have chosen. In order to accomplish this goal, its path for storage on the disc (the position of storage) must be known. This can be accomplished in a number of different ways.

You can begin the compilation process by using the configuration file of your programme. In this technique, you will need to specify the directory for the :mnesia (:dir) command. And then there is the second technique, which is the function of the same function and is carried out in the form of run time.

Example

  MnesiaAssistant.set_dir("/tmp/db") # --> Application.put_env(:mnesia, :dir, dir)copy

In order to fulfil the requirements of the Elixir project, it is necessary for you to activate this database in addition to executing the mnesia function within the mix.exs file. Both activation and information for determining whether or not it is active are accomplished through the utilisation of these functions.

Two distinct variants of this function have been generated for your use. It is important to note that the start/0 function is a wrapper from Erlang, while the second function is responsible for activating mnesia in Elixir (start/1 :: :app).

In order to activate programmes, we utilise the start/1 command with the input :app.

Example

  MnesiaAssistant.start() # --> :mnesia.start()
  # OR
  MnesiaAssistant.start(:app) # --> Application.start(:mnesia)copy

Read start/0 document.

This function determines whether or not the mnesia function is active. The output of the Application.started_applications() function is what this function actually searches for.

Example

  MnesiaAssistant.started?()copy

You have the ability to disable mnesia by using the function. In the same way that the start/0 function has two forms, this function also has two forms. One of the forms is a wrapper for the mnesia function itself, while the other form disables the mnesia Elixir red applications that have been active.

Example

  MnesiaAssistant.stop() # --> :mnesia.stop()
  # OR
  MnesiaAssistant.stop(:app) # --> Application.stop(:mnesia)copy

Read stop/1 document.

Using this function, you will be able to subscribe to Mnesia's activities and events, and you will receive notifications immediately after an event takes place. For example, if you are using GenServer and you want to carry out a particular activity in real time based on a strategy, you can make use of this method.

Example

  MnesiaAssistant.subscribe({:table, Person})
  # -> :mnesia.subscribe({:table, table})
  MnesiaAssistant.subscribe({:table, Person, simple_detailed})
  # -> :mnesia.subscribe({:table, table, simple_detailed})
  MnesiaAssistant.subscribe(what)
  # -> :mnesia.subscribe(what)
  # What = system | activity | {table, table(), simple | detailed}copy

In order to terminate your subscription to mnesia, you can use the following function. For more information read subscribe/1

Example

MnesiaAssistant.unsubscribe({:table, Person})
# -> :mnesia.unsubscribe({:table, table})
MnesiaAssistant.unsubscribe({:table, Person, simple_detailed})
# -> :mnesia.unsubscribe({:table, table, simple_detailed})
MnesiaAssistant.unsubscribe(what)
# -> :mnesia.unsubscribe(what)
# What = system | activity | {table, table(), simple | detailed}copy