[erlang-questions] MNESIA ram-only
Roberto Ostinelli
roberto.ostinelli@REDACTED
Mon Mar 9 21:28:20 CET 2015
Hi Dan,
The default is actually disc_opt which then falls back to ram (since there's no schema on disk).
My question though is: any risks / other tradeoffs I should be aware of by doing this, instead of having a disk schema?
Thanks,
r.
> On 09/mar/2015, at 21:19, Dan Gudmundsson <dangud@REDACTED> wrote:
>
> Sure, you do not need to specify schema_location ram since that is the default if
> no schema exists on disc.
>
> Just be sure that all nodes in cluster are in the nodes() list.
>
> /Dan
>
>> On Mon, Mar 9, 2015 at 4:11 PM, Roberto Ostinelli <roberto@REDACTED> wrote:
>> Dear list,
>> I am starting MNESIA in RAM only mode, with the option [1]:
>>
>> -mnesia schema_location ram.
>>
>> Every time I start a gen_server, I first ensure to add all the other nodes in the island like so:
>>
>> mnesia:change_config(extra_db_nodes, [node() | nodes()]).
>>
>> I then create the table I need:
>>
>> mnesia:create_table(cometa_online_devices, [
>> {type, set},
>> {ram_copies, [node() | nodes()]},
>> {attributes, record_info(fields, my_record)},
>> {index, [#my_record.pid]},
>> {storage_properties, [{ets, [{read_concurrency, true}]}]}
>> ])
>>
>> I do so mainly to avoid the hassle of creating a schema. As you can see I only use ram tables.
>>
>> My question here is: is this an appropriate use? What kind of problems may I get myself into by not using a disc schema?
>>
>> Thank you,
>> r.
>>
>>
>>
>> [1] http://www.erlang.org/doc/apps/mnesia/Mnesia_chap5.html#id76396
>>
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>
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