Re: Slow query due to slow I/O

On Thu, Dec 12, 2013 at 5:10 PM, Bryce Covert
<bryce(at)brycecovertoperations(dot)com> wrote:
> Hi,
>
> I'm seeing a slow running query. After some optimization with indexes, it
> appears that the query plan is correct, it's just slow. Running the query
> twice, not surprisingly, is very fast, due to OS caching or shared_buffers
> caching. If the parameters for the query are different, however, the query
> is slow until run a second time. In our usage pattern, this query must run
> fast the first time it runs.
>
> A couple of general stats: this is a linode machine with a single 3GB DB
> with 4GBs of ram. Shared buffers = 1024mb, effective_cache_size=2048MB. We
> are running with postgres 9.1. The machine is otherwise dormant when this
> query runs. Here is the schema:

For this kind of diagnostic, you need to include hardware details.

OS? Disks? RAID?