update

apps/mnesia_debug/src/mnesia_debug.erl

@@ -100,11 +100,13 @@ create_schema(Nodes, Aliases)
       Alias      :: alias(),
       Table      :: table(),
       Properties :: proplists:proplist(),
-      Return     :: table().
+      Return     :: ok
+                  | {error, term()}.
       
 create_table(Alias, Table, Properties) -> 
     ?LOG_DEBUG("~p",[{?MODULE, self(), create_table, [Alias, Table, Properties]}]),
-    throw({todo, ?MODULE, create_table, [Alias, Table, Properties]}).
+    % throw({todo, ?MODULE, create_table, [Alias, Table, Properties]}).
+    ok.
 
 %%--------------------------------------------------------------------
 %% @doc Close an open and active table. This callback is called by
@@ -128,7 +130,8 @@ create_table(Alias, Table, Properties) ->
 
 close_table(Alias, Table) -> 
     ?LOG_DEBUG("~p",[{?MODULE, self(), close_table, [Alias, Table]}]),
-    throw({todo, ?MODULE, close_table, [Alias, Table]}).
+    % throw({todo, ?MODULE, close_table, [Alias, Table]}).
+    ok.
 
 %%--------------------------------------------------------------------
 %% @doc Initialize the environment for the backend. This callback is
@@ -156,11 +159,13 @@ init_backend() ->
       Table      :: table(),
       Nodes      :: nodes(),
       Properties :: proplists:proplist(),
-      Return     :: ok.
+      Return     :: ok
+                  | {ok, Properties}.
 
 check_definition(Alias, Table, Nodes, Properties) ->
     ?LOG_DEBUG("~p",[{?MODULE, self(), check_definition, [Alias, Table, Nodes, Properties]}]),
-    throw({todo, ?MODULE, check_definition, [Alias, Table, Nodes, Properties]}).
+    % throw({todo, ?MODULE, check_definition, [Alias, Table, Nodes, Properties]}).
+    {ok, Properties}.
 
 %%--------------------------------------------------------------------
 %% @doc Delete a key in an opened and active table. This callback is
@@ -206,7 +211,8 @@ delete(Alias, Table, Key) ->
 
 delete_table(Alias, Table) -> 
     ?LOG_DEBUG("~p",[{?MODULE, self(), delete_table, [Alias, Table]}]),
-    throw({todo, ?MODULE, delete_table, [Alias, Table]}).
+    %throw({todo, ?MODULE, delete_table, [Alias, Table]}).
+    ok.
 
 %%--------------------------------------------------------------------
 %% @doc this callback is called by `mnesia_lib:db_fixtable/3'.

apps/mnesia_debug/src/mnesia_debug_app.erl

@@ -0,0 +1,13 @@
+%%%===================================================================
+%%% @doc
+%%% @end
+%%%===================================================================
+-module(mnesia_debug_app).
+-behavior(application).
+-export([start/2, stop/1]).
+
+start(_StartType, _StartArgs) ->
+    mnesia_debug_sup:start_link().
+
+stop(_State) ->
+    ok.

apps/mnesia_debug/src/mnesia_debug_sup.erl

@@ -0,0 +1,19 @@
+%%%===================================================================
+%%% @doc
+%%% @end
+%%%===================================================================
+-module(mnesia_debug_sup).
+-behaviour(supervisor).
+-export([start_link/0]).
+-export([init/1]).
+
+start_link() ->
+    supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+init([]) ->
+    SupFlags = #{ strategy => one_for_all
+                , intensity => 0
+                , period => 1
+                },
+    ChildSpecs = [],
+    {ok, {SupFlags, ChildSpecs}}.

notes/0001-creating-custom-mnesia-backends-from-scratch/README.md

@@ -85,7 +85,10 @@ mnesia:create_table( my_table
                    , [{custom_mnesia_backend, [node()]}
                    , {storage_properties, Storage}]).
 ```
-    
+
+ 8. Mnesia will call then `CustomModule:check_definition/4` function
+    callback and should check the properties of the table.
+
 
 ## Backend Definition and Interfaces
 
@@ -93,6 +96,17 @@ mnesia:create_table( my_table
 
 ### `Module:add_aliases/1`
 
+Example of debugging message:
+
+```erlang
+{ mnesia_debug
+, <0.1032.0>
+, add_aliases
+, [[mnesia_backend_debug]
+  ]
+}
+```
+
 ### `Module:semantics/2`
 
 Based on `mnesia_rocksdb` implementation, `semantics/2` is needed to
@@ -109,6 +123,138 @@ define which kind of plugins are supported by this backend.
       semantics(_Alias, any()) -> undefined.
 ```
 
+Example of debugging message:
+
+```erlang
+{mnesia_debug,<0.1832.0>,semantics,[mnesia_backend_debug,index_types]}
+{mnesia_debug,<0.1832.0>,semantics,[mnesia_backend_debug,storage]}
+{mnesia_debug,<0.1832.0>,semantics,[mnesia_backend_debug,types]}
+```
+
+### `Module:check_definition/4`
+
+Example of debugging message, where `t3` is the name of table:
+
+```erlang
+{ mnesia_debug
+, <0.385.0>
+, create_table
+, [ mnesia_backend_debug
+  , t3
+  , [ {name,t3}
+    , {type,set}
+    , {ram_copies,[]}
+    , {disc_copies,[]}
+    , {disc_only_copies,[]}
+    , {mnesia_backend_debug,[nonode@nohost]}
+    , {load_order,0}
+    , {access_mode,read_write}
+    , {majority,false}
+    , {index,[]}
+    , {snmp,[]}
+    , {local_content,false}
+    , {record_name,t3}
+    , {attributes,[key,val]}
+    , {user_properties,[]}
+    , {frag_properties,[]}
+    , {storage_properties,[{mnesia_backend_debug,[]}]}
+    , {cookie,{{1699140080964593704,-576460752303423483,1},nonode@nohost}}
+    , {version,{{2,0},[]}}
+    ]
+]}
+```
+
+### `Module:close_table/2`
+
+Example of debugging message, where `t3` is the name of table:
+
+```erlang
+{ mnesia_debug
+, <0.1832.0>
+, close_table
+, [mnesia_backend_debug,t3]
+}
+```
+
+Example of debugging message, where `t3` is the name of table:
+
+### `Module:delete_table/2`
+
+```erlang
+{ mnesia_debug
+, <0.2152.0>
+, delete_table
+ , [mnesia_backend_debug,t3]
+}
+```
+
+### `Module:create_table/3`
+
+Example of debugging message, where `t3` is the name of table:
+
+```erlang
+{ mnesia_debug
+, <0.385.0>
+, create_table
+, [ mnesia_backend_debug
+  , t3
+  , [ {name,t3}
+    , {type,set}
+    , {ram_copies,[]}
+    , {disc_copies,[]}
+    , {disc_only_copies,[]}
+    , {mnesia_backend_debug,[nonode@nohost]}
+    , {load_order,0}
+    , {access_mode,read_write}
+    , {majority,false}
+    , {index,[]}
+    , {snmp,[]}
+    , {local_content,false}
+    , {record_name,t3}
+    , {attributes,[key,val]}
+    , {user_properties,[]}
+    , {frag_properties,[]}
+    , {storage_properties,[{mnesia_backend_debug,[]}]}
+    , {cookie,{{1699140992521145194,-576460752303422015,1},nonode@nohost}}
+    , {version,{{2,0},[]}}
+    ]
+]}
+```
+
+### `Module:load_table/4`
+
+Example of debugging message, where `t3` is the name of table:
+
+```erlang
+{ mnesia_debug
+, <0.389.0>
+, load_table
+, [ mnesia_backend_debug
+  , t3
+  , {dumper,create_table}
+  , [ {name,t3}
+    , {type,set}
+    , {ram_copies,[]}
+    , {disc_copies,[]}
+    , {disc_only_copies,[]}
+    , {mnesia_backend_debug,[nonode@nohost]}
+    , {load_order,0}
+    , {access_mode,read_write}
+    , {majority,false}
+    , {index,[]}
+    , {snmp,[]}
+    , {local_content,false}
+    , {record_name,t3}
+    , {attributes,[key,val]}
+    , {user_properties,[]}
+    , {frag_properties,[]}
+    , {storage_properties,[{mnesia_backend_debug,[]}]}
+    , {cookie,{{1699140992521145194,-576460752303422015,1},nonode@nohost}}
+    , {version,{{2,0},[]}}
+    ]
+]}
+```
+
 ## Backend Example
 
  - [ ] starting a custom backend with `mnesia_debug` backend (within