Tom Lane wrote:
> It's interesting to speculate about where we could draw an abstraction
> boundary that would be more useful. I don't think the MySQL guys got it
> right either...
The supposed smgr abstraction of PostgreSQL, which tells more or less
how to get a byte to the disk, is quite far away from what MySQL calls a
storage engine, which has things like open table, scan table, drop table
on a logical level (meaning open table, not open heap).
To my judgement, neither of these approaches is terribly useful from a
current, practical point of view.
In any case, in order to solve the "where to abstract" question, you'd
probably want to have one or two other storage APIs that you seriously
want to integrate, and then you can analyze how to unify them.