Mnesia dB size limits

Philip Robinson <>
Wed Aug 30 17:10:50 CEST 2006


Damir asks:

>What are the upper limits where system can still be called
>"production quality" in terms of dB speed?

I was once writing a program that needed to retrieve events
within a date/time range from an mnesia table, and found that it
did not seem to be hitting the index.  It would scan the entire
1-million-plus records every query... dead slow.

When I wanted to retrieve a specific event there was no noticable
delay, but most of my queries were for a date/time range.

I think the mnesia issues being mentioned on this list were to do
with database recovery across nodes after a node failure...?


>[E] ->
>     B = E#account.balance,
>		{ok, B}
>	end
>...
>
>Why not skip B and send {ok, E#account.balance} in the fist place?

When I see code like that in my programs it is because there used to
be something like "io:format("~w~n", [B])," between the two lines.

Out of habit I always assign to a temporary value to ensure that what
is printed out is exactly what is used later (in case of typos).

Cheers,
Philip





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