Thread: random_page_cost = 1?

Is this advisable? The disks are rather fast (15k iirc) but somehow I
don't think they are covered in whatever magic fairy dust it would
require for a sequential read to be as fast as a random one. However
I could be wrong, are there any circumstances when this is actually
going to help performance?

Alex Stapleton <alexs@advfn.com> writes:
> Is this advisable?

Only if your database is small enough that you expect it to remain fully
cached in RAM.  In that case random_page_cost = 1 does in fact describe
the performance you expect Postgres to see.

People occasionally use values for random_page_cost that are much
smaller than physical reality would suggest, but I think this is mainly
a workaround for deficiencies elsewhere in the planner cost models.

            regards, tom lane