[erlang-questions] mnesia async vs sync

Ryan <>
Thu Mar 10 23:58:14 CET 2016


On 03/10/2016 04:53 PM, Roberto Ostinelli wrote:
> Dear list,
> To my understanding the main difference between the mnesia sync and async activities is that the latter does not wait for a confirmation from all the nodes that a write has been successful before returning.
>
> Thus, I would expect that the write speed of an async activity remains similar even when the number of node increases; however according to my benchmarks this is not true. The write speed decreases when the number of nodes increase.
>
> Can someone enlighten me of why this is?
>
> Thank you in advance.
>
A quick glance through the mnesia module suggests that async doesn't 
mean 100% fire and forget. It appears that some cluster messaging is 
still performed before returning on a call with Kind=async. That would 
suggest that larger clusters will have slower performance. I don't know 
mnesia, so I can't give any further insight than that.


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