Re: Reason of Slowness of query

23.03.11 08:28, Adarsh Sharma написав(ла):

I perform a join query on it as :

 explain analyze select distinct(p.crawled_page_id) from page_content p , clause2  c where p.crawled_page_id != c.source_id ;

Your query is wrong. This query will return every crawled_page_id if clause2 has more then 1 source_id. This is because DB will be able to find clause with source_id different from crawled_page_id. You need to use "not exists" or "not in".

Best regards, Vitalii Tymchyshyn.