Mnesia vs Postgres - a very very simple benchmark

At this stage, part of the solution seems to be a mix of Mnesia and some RDBMS, Postgres for example.

Data that is accessed often can be stored in Mnesia (RAM + disc), like categories and products.

Data that is seldom used, like orders, can be stored in Postgres.

To just a get an idea of the difference in speed between Mnesia and Postgres I wrote a very very basic (and not so basic-in-reality) benchmark. 100 000 writes inserting an id and a name (the same name) and the same amount of reads.

Name               ips     average  deviation     median     99th %
4mnesia_read     18.23    0.0549 s     ±8.93%   0.0535 s   0.0675 s
3mnesia_write     2.32      0.43 s     ±3.69%     0.43 s     0.45 s
2ecto_read      0.0533     18.76 s     ±0.00%    18.76 s    18.76 s
1ecto_write     0.0358     27.90 s     ±0.00%    27.90 s    27.90 s

Writing something that interacts conveniently with Mnesia, which is just a key-value-storage, might take some time. But to get such a speed boost should be worth quite a few lines of code.

Later on I plan to perform a more reality-based benchmark, when a products-and-categories-in-Mnesia-layer has been written.