The other parameter you might want to look at is effective_cache_size -
increasing it will encourage index use. On a machine with 16GB the
default is probably too small (there are various recommendations about
how to set this ISTR either Scott M or Greg Smith had a page somewhere
that covered this quite well - guys?).
Obviously, decreasing random_page_cost fixed this query for you, but if
find yourself needing to tweak it again for other queries, then look at
changing effective_cache_size.
Cheers
Mark
Adonias Malosso wrote:
> Set random_page_cost = 2 solved the problem. thanks
>