[erlang-questions] refactoring a very large record

Joel Reymont <>
Thu Oct 20 16:21:15 CEST 2011


On Oct 20, 2011, at 3:14 PM, Jesper Louis Andersen wrote:

> I always hesitate when I hear about large records of this size. If
> they are only read, or mostly read, they tend to be fast. But they
> don't support updates very well as it requires you to write a new
> record object of size 80.

Are you sure?

Doesn't the record tuple keep pointers to each element and only updates changes the modified pointers on update?

> I tend to have modules that operate on records.

Aye! I'm doing this now. 

> I rarely access the record
> directly, but I export "views" of the data in the record which i can
> pattern match on outside.

What does this mean?

I thought that by making the record opaque you lose the ability to pattern-match on it.

> You can store the 80-element tuple in ETS which is
> expensive as you copy the tuple to the ETS store.

Not this way. 

Think of record keys being individual keys in ETS instead.

> Another viable option is to make the 80-record tuple into a process.
> Then one can move some of the work to the tuple itself rather than
> querying for it and then acting upon it locally in processes.

Message passing was 10x slower than function calls last time I checked ;-).

	Thanks, Joel

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