Rank Function and very poor performance.
399318Feb 17 2009 — edited Feb 17 2009Hi,
I'm ranking visits to a page and have this code, but for the data volumn 14Million rows and more,
this takes hours. Please suggest as how I can speed this up...
update table a
set theme_rank = (
select rank_theme from (
select /*+parallel( table, 4 ) */
theme_desc,
rank( ) over( order by sum( visits ) desc nulls last ) rank_theme
from table
group by theme_desc
) b where a.theme_desc = b.theme_desc
);
Thanks.