Re: query plan question, nested loop vs hash join

Thanks for your reply, Marti, as I answered to Tom couple of days ago
adjusting of 'effective_cache_size' to 80% of RAM and 'random_page_cost'
from 2 to 1 helped me.

On 8 October 2014 00:26, Marti Raudsepp <marti(at)juffo(dot)org> wrote:

> On Fri, Oct 3, 2014 at 6:38 PM, Andrey Lizenko <lizenko79(at)gmail(dot)com>
> wrote:
> > Is it possible to force optimizer choose the second plan without doing
> "set
> > enable_hashjoin = off;" ?
> >
> > Increasing of 'effective_cache_size' leads to similar thing with
> mergejoin,
> > other options (work_mem, shared_buffers. etc) do not change anything.
>
> Have you tried changing random_page_cost?
>
> In small databases where most of the data is cached anyway, lowering
> random_page_cost to somewhere between 1 and 2 usually leads to better
> planner decisions.
>
> Regards,
> Marti
>

--
С уважением, Андрей Лизенко