[erlang-questions] Mnesia, disk_log and dets

Ulf Wiger <>
Wed Feb 17 07:39:48 CET 2010


wde wrote:
> hello,
> 
> I'm reading the source code of Mnesia to understand how things work
> :+) If I have understood correctly, for "disc_copies" tables, data
> are written to disc by using the "disk_log" module. For
> "disc_only_copies" tables, Mnesia uses "dets".
> 
> What not use the same disk backend ?

Originally, they did use the same back-end, but it turned out,
from experimentation, that dumping the entire table using disk_log
was /much/ faster than writing out the individual changes into
a dets file.

BR,
Ulf W
-- 
Ulf Wiger
CTO, Erlang Solutions Ltd, formerly Erlang Training & Consulting Ltd
http://www.erlang-solutions.com
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