On Mon, Jun 24, 2013 at 11:55 AM, Emrah Mehmedov
<emrah.mehmedov@x3mlabs.com> wrote:
> Marcin: This heppens everytime when i try to query different keyword in FTS
> for example:
>
> firsttime: query: "Hello & World" 15sec~
> secondtime: query: "Hello & World" 2-3sec
>
> then new query
>
> firsttime: query: "We & are & good" 10sec~
> secondtime: query: "We & are & good" 2-3sec
>
Now it looks like Postgres is fetching data from disk on first query
run, the second time it is from cache, so faster. Try:
EXPLAIN(ANALYZE, BUFFERS) SELECT title, url, ts_rank_cd(vector, query)
AS rank FROM links, to_tsquery('english', 'risk') query WHERE query @@
vector ORDER BY rank DESC LIMIT 10;
with varying queries, and post the results. This will show how many
blocks are are read from shared buffers, and how many are read from
the OS(either from OS disk cache, or the actual disk).
Regards
Marcin Mańk