Re: Distributing data over "spindles" even on AWS EBS, (followup to the work queue saga)

On 3/14/19 07:53, Gunther wrote:
> 2. build a low level "spreading" scheme which is to take the partial
> files 4653828 and 4653828.1, .2, _fsm, etc. and move each to another
> device and then symlink it back to that directory (I come back to this!)
...
> To 2. I find that it would be a nice feature of PostgreSQL if we could
> just use symlinks and a symlink rule, for example, when PostgreSQL finds
> that 4653828 is in fact a symlink to /otherdisk/PG/16284/4653828, then
> it would
>
> * by default also create 4653828.1 as a symlink and place the actual
> data file on /otherdisk/PG/16284/4653828.1

How about if we could just specify multiple tablespaces for an object,
and then PostgreSQL would round-robin new segments across the presently
configured tablespaces? This seems like a simple and elegant solution
to me.

> 4. maybe I can configure in AWS EBS to reserve more IOPS -- but why
> would I pay for more IOPS if my cost is by volume size? I can just
> make another volume? or does AWS play a similar trick on us with
> IOPS being limited on some "credit" system???

Not credits, but if you're using gp2 volumes then pay close attention to
how burst balance works. A single large volume is the same price as two
striped volumes at half size -- but the striped volumes will have double
the burst speed and take twice as long to refill the burst balance.

-Jeremy

--
Jeremy Schneider
Database Engineer
Amazon Web Services