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Thanks Chetan, After my Lunch Break, I tried the below steps : My original query was : explain analyze select distinct(p.crawled_page_id) from page_content p , clause2 c where p.crawled_page_id != c.source_id which hangs because it is wrong query to fetch the desired output . Next Updated Query be Chetan Suttraway : explain analyze select distinct(p.crawled_page_id) from page_content p where NOT EXISTS (select 1 from clause2 c where c.source_id = p.crawled_page_id); QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------------------------- HashAggregate (cost=100278.16..104104.75 rows=382659 width=8) (actual time=7192.843..7195.923 rows=72 loops=1) -> Nested Loop Anti Join (cost=0.00..99320.46 rows=383079 width=8) (actual time=0.040..7192.426 rows=74 loops=1) -> Seq Scan on page_content p (cost=0.00..87132.17 rows=428817 width=8) (actual time=0.009..395.599 rows=428467 loops=1) -> Index Scan using idx_clause2_source_id on clause2 c (cost=0.00..18.18 rows=781 width=4) (actual time=0.014..0.014 rows=1 loops=428467) Index Cond: (c.source_id = p.crawled_page_id) Total runtime: 7199.748 ms (6 rows) I think it is very much faster but I don't understand the query : explain select distinct(b) from t1,t2 where t1.b >t2.d union all select distinct(b) from t1,t2 where t1.b <t2.d; As i transform it into my format as: explain select distinct(p.crawled_page_id) from page_content p , clause2 c where p.crawled_page_id > c.source_id union all select distinct(p.crawled_page_id) from page_content p,clause2 c where p.crawled_page_id < c.source_id; QUERY PLAN --------------------------------------------------------------------------------------------------------------------- Append (cost=0.00..296085951076.34 rows=765318 width=8) -> Unique (cost=0.00..148042971711.58 rows=382659 width=8) -> Nested Loop (cost=0.00..136655213119.84 rows=4555103436696 width=8) -> Index Scan using idx_page_id on page_content p (cost=0.00..174214.02 rows=428817 width=8) -> Index Scan using idx_clause2_source_id on clause2 c (cost=0.00..185898.05 rows=10622488 width=4) Index Cond: (p.crawled_page_id > c.source_id) -> Unique (cost=0.00..148042971711.58 rows=382659 width=8) -> Nested Loop (cost=0.00..136655213119.84 rows=4555103436696 width=8) -> Index Scan using idx_page_id on page_content p (cost=0.00..174214.02 rows=428817 width=8) -> Index Scan using idx_clause2_source_id on clause2 c (cost=0.00..185898.05 rows=10622488 width=4) Index Cond: (p.crawled_page_id < c.source_id) (11 rows) I don't think this is correct because it produce 11 rows output. Any further suggestions, Please guide. Thanks & best Regards, Adarsh Sharma |
