Re: per-tablespace random_page_cost/seq_page_cost

Robert,

> As to (1), my thought is to add two new float8 columns to
> pg_tablespace.  The naming is a little awkward, because
> random_page_cost and seq_page_cost would not fit with our (rather odd)
> convention for naming system catalog columns.  I'm tempted to call
> them spcrandompagecost and spcseqpagecost, but I wonder if anyone has
> any strong preferences.

I'm thinking an array, in case we want to make other tablespace cost
parameters in the future.*  Or, better, whatever structure we're
currently using for ROLEs.

(* for example, if someone does manage a filesystem with a separate
cache space per mount, then we'd want effective_cache_size to be
tablespace-based as well)

--Josh