[erlang-questions] Mnesia table per user?

Ulf Wiger <>
Tue Nov 28 00:14:38 CET 2006


Den 2006-11-27 16:37:35 skrev Pat e <>:

> I am thinking about using Partition Attributes Across (PAX) modeling
> for our db.
> Now besides using mutual attributes for all users (gender, address,
> .....) we are thinking about using a table for each customer forum
> comments, blogs, personal correspondence....

That is certainly elegant in some ways, but...


> Now would it be resource wise to have table with binary data in it for
> each user, counting by 100,000 - 1MM users??

For that many users, you won't be able to have a table each.
Each erlang node is limited to around 50,000 ets tables
(the limit is configurable, but that's the ballpark, I think.
In the old days, there were some parts in the ets code that
would actually do a linear seach through the table of tables.)

Also, mnesia will do fine with a few thousand tables, but
will probably be in deep trouble with a million. The table
loading code is not designed for that.

BR,
Ulf W

-- 
Ulf Wiger



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